The contents of the twenty-seven FAQ files available are described below.
Select FAQ-15 to obtain content listed below
15.01 -( Make Slides from Negatives using Kodak SO-279 )15.02 -( What is Angle of View of any Lens on any Camera? )15.03 -( Color Crossover, Color Conversion and Temperature )15.04 -( 5 vs. 7 sprocket format stereo cameras )15.05 -( Several observations about Kodak B&W IR film )15.06 -( Precision Pinhole Parts for Pinhole Photographers )15.07 -( Reversal Processing of Black and White paper )15.08 -( Making POLAROID Color Transfer Prints )15.09 -( Sample Model Release )Select FAQ-16 to obtain content listed below
16.01 -( More Model Releases )16.02 -( Pinout Layout for Kodak Projector's remote control )16.03 -( PINHOLE Photography Book List )16.04 -( Reciprocity Failure - Folk and Real Description )16.05 -( Toners - home made stuff )16.06 -( Thermography = Infrared Photography of Hot Objects )16.07 -( Reverse Text Slides on Vericolor Slide Film )16.08 -( Flange to Film Distances for Photo Hackers )16.09 -( EV or Exposure Values Explained )16.10 -( How to process with Rodinal )16.11 -( Processing B&W Film in various developers )16.12 -( Making Polycontrast Filters with CC filtration )16.13 -( How to use Direct Positive Film )Select FAQ-17 to obtain content listed below
17.01 -( Infrared - basic information )17.02 -( Stereo Photography Discussion )17.03 -( Compensation for Enlarger Magnification in "C" )17.04 -( Pinhole Photography Primer )17.05 -( Processing Infrared Film - How To )17.06 -( How to use Tech Pan in Medium Format )17.07 -( How to determine intermediate f stops )17.08 -( Making a home-made light slave trigger for flashes )17.09 -( FTP file for material in Rec.Photo )Select FAQ-18 to obtain content listed below
18.01 -( Depth of Field Calculation )18.02 -( How to Dispose of Darkroom Chemicals Safely )18.03 -( Depth of Field in C )18.04 -( Basic Stereo and Parallax Concepts )18.05 -( More Advanced Stereo Concepts and Stereo FTP site )18.06 -( Photometry and Light Meters Primer )18.07 -( More on Polaroid Transfer Process )18.08 -( Tailflash Synchronizer Circuits )18.09 -( Some aerial photography Tips )18.10 -( Where to get film for SUBMINIATURE cameras )Select FAQ-19 to obtain content listed below
19.01 -( Making an Improvised Infrared Transmitting Filter )-
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19.02 -( Fishing for a lost Leader! )19.03 -( Some Basic Infrared Photography Information )19.04 -( Checklists for Wedding Photography )19.05 -( Standardized Mounting of Stereo Slides )19.06 -( Wedding Photography - More Tips )19.07 -( Using "flash" exposure to lower print contrast )19.08 -( Reloading One-Use Cameras )19.09 -( What is DENSITY? )19.10 -( Discontinued Film Sizes @ Film for Classics )Select FAQ-20 to obtain content listed below
20.01 -( Flash Sync Speed Question and Answer )20.02 -( Kodak Lenses - characteristics and applications )20.03 -( Masking to change contrast esp. for Ilfochrome use )20.04 -( 3D FAQ or Frequently Asked Questions about stereo )20.05 -( Making Color out of B&W! )20.06 -( Variable Contrast Filter Settings and Color Heads )20.07 -( Tech Pan Exposure/Processing Info )20.08 -( Sound Synchronizers - Cheap and Simple )20.09 -( Convenient Pulfrich Effect 3D Viewing )20.10 -( What is EV (Exposure Value)? )20.11 -( Info on Film and Video Resources on the Internet )Select FAQ-21 to obtain content listed below
21.01 -( A DOF program written in C FYI )21.02 -( Polaroid batteries and accessories )21.03 -( Infrared Ektachrome Processing in E-6 chemicals )21.04 -( New f# when using bellows extension )21.05 -( Data on Wratten Filters by the Numbers )21.06 -( CHEAP IR Filters - experimental quality )21.07 -( UV and IR Technique Basics )21.08 -( Solarization Tip )21.09 -( Create-a-Print used for B&W printing )21.10 -( Decoding De DX Code )21.11 -( IR Ektachrome Processing in cool E6 chemicals )Select FAQ-22 to obtain content listed below
22.01 -( Sunrise/Sunset location finder BASIC program )22.02 -( Simple Sound Switch to trigger Flash )22.03 -( Make Black Borders or Lines around your images )22.04 -( Sound Synchronizer for ECM application )22.05 -( Pinout Layout for Carousel Projector Receptacle )22.06 -( Foot-candles - how to measure them? )22.07 -( Film Acceleration )22.08 -( IR Film Data Sheet )22.09 -( Circular Polarizers - better than square ones? )Select FAQ-23 to obtain content listed below
23.01 -( Speed Graphic FAQ file )23.02 -( Physical Development Process )23.03 -( Electronic Flash Circuit - fundamental )23.04 -( DX demystified and controlled )23.05 -( Photo Discussion Groups on the Internet )-
file:///C|/faq.html (2 of 555) [7/19/2002 3:46:22 AM]
23.06 -( Sprayable B&W emulsion Source )23.07 -( Guide Numbers - what are they? )Select FAQ-24 to obtain content listed below
24.01 -( Harris Shutter - making and using it! )24.02 -( Electronic Visualization of Color Negatives )24.03 -( Film Codes Demystified )24.04 -( Obsolete Film Processing )24.05 -( Canon A1 control contacts described )24.06 -( Copyright - basic information )24.07 -( Bellows Source )24.08 -( Cross Processing Benchmark )24.09 -( Postcard Printer Pointer )24.10 -( Hyperfocal Distances for short 35mm lenses )24.11 -( Photo Manufacturers and Distributors list )Select FAQ-25 to obtain content listed below
25.01 -( Daguerreotype Info from 1858 available on-line )25.02 -( List of Photo/Imaging Books, Magazines, etc. )25.03 -( Basic Photo Lesson w/pinhole camera )25.04 -( Tips for use of PhotoFlo )25.05 -( Remote Camera Triggering Discussion )25.06 -( More on Polarizing Filters! )25.07 -( Kodak 2481 HS Infrared Film Data Sheet )Select FAQ-26 to obtain content listed below
26.01 -( Aluminum Frames - where to buy them? )26.02 -( Polarizing and UV filters - Q and A )26.03 -( Diffraction, Depth of Field, Color Temp. and Common Sense )26.04 -( Guide for Forte Films used in Kodak Developers )26.05 -( Making Duplicate Slides with Enlarger )26.06 -( Duplicating Slides - Procedures and Films )26.07 -( 18% Gray Card Reference Articles )26.08 -( Cross-processing - what goes on? )26.09 -( Commercial Silver Recovery Units FYI )Select FAQ-27 to obtain content listed below
27.01 -( BIG photographers databank!!!! )27.02 -( California Museum of Photography on Internet )27.03 -( Dealing with VERY contrasty negatives )27.04 -( Contrast Control with the Sterry Process )27.05 -( PSA (Photo Society of America) address )27.06 -( Comprehensive Copyright Info Source )27.07 -( Photokina address in US )27.08 -( Basic Astrophotography Pointers and Info )27.09 -( Image Usage Rights - A primer )27.10 -( Photo Artisans Guild info )27.11 -( Reversal Processing of Ilford Films )27.12 -( Bellows - basic instruction in making one )27.13 -( Kodak's Ultra Fast and Ultra Grainy Recording Film )Select FAQ-28 to obtain content listed below
28.01 -( Lost Film Leader Retriever - Making Improvised One )-
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28.02 -( Using Camera Meter to determine Foot Candles )28.03 -( Reloading Unreloadable Cassettes with Bulk Film )28.04 -( Circular vs. Linear Polarizers - more scoop )28.05 -( Depth of Field - a formula approach )28.06 -( pointer on better photographs of nudes )28.07 -( Exposure Correction in Enlarging )28.08 -( Pinholes, f#s and proper exposure Determination )28.09 -( Optimum Pinhole Diameter - Further Suggestions )28.10 -( Painting with Light basics )28.11 -( IR _BLOCKING_ filters - what/where/why? )28.12 -( Underwater Dome Ports - a mathematical approach )28.13 -( Catadioptric Lenses - brief description )28.14 -( Tintype Parlor - tintype materials suppliers )28.15 -( Adhering Liquid Light to Glass )28.16 -( Pro School Photographers Association info )28.17 -( ISO, DIN and ASA speed relationships )Select FAQ-29 to obtain content listed below
29.01 -( Where to process Infrared Color Film )29.02 -( 3D Processing and Finishing Laboratories )29.03 -( Star Trail Control with Exposure Time )29.04 -( Problem with Glass Carriers and Rings on Prints )29.05 -( Black Light )29.06 -( Minox Cameras Dated and Described )29.07 -( Filter Primer )29.08 -( Is Photography a Language? )29.09 -( Hundreds of Film/Developer Processing Instructions )Select FAQ-30 to obtain content listed below
30.01 -( Making Masks to Make Money w/ Trading Cards )30.02 -( More Wedding Photography Tips )30.03 -( Photo Archives of an old Photo Discussion list )30.04 -( 8mm and 16mm film source and brief movie primer )30.05 -( Pinhole Cameras and Supplies Source )30.06 -( What shutter speed to STOP motion? )30.07 -( Filter to make color scene look as B&W sees it! )30.08 -( Polarizers for Infrared Photography - Q&A )30.09 -( What makes a macro photograph? )30.10 -( Making B&W slides from B&W negatives )30.11 -( Photo Attractions in Boston, Chicago, Las Vegas & Mobile )30.12 -( Favorite Textbooks of PhotoForum readers )30.13 -( The Argyrotype Process )Select FAQ-31 to obtain content listed below
31.01 -( Porter's Camera Store and Catalogue info )31.02 -( Light/Dark and Sound Sync w/delay & intervalometer )31.03 -( Kodak B&W Sheet Film notch codes )31.04 -( US Photography Related Magazines List )31.05 -( X-Ray machines at airports )31.06 -( Testing Shutters the SIMPLE way )31.07 -( Copying Artwork with Tungsten Lights discussion )31.08 -( What is a TLR in reference to a camera? )31.09 -( Another note on 2nd curtain sync )31.10 -( Photo Related URLS - HUGE list )file:///C|/faq.html (4 of 555) [7/19/2002 3:46:22 AM]
Select FAQ-32 to obtain content listed below
32.01 -( Manufacturers and Distributors of Rotating Panoramic Cameras )32.02 -( Several observations on rotating panoramic cameras )32.03 -( Comments on panoramic photography requirements )32.04 -( Pointers on drying Fiber Based papers )32.05 -( Dividing 1 gal E-6 for small batch processing )32.06 -( High Speed Photography Sample Exam - Questions and Answers )32.07 -( The Royal Photographic Society - Info )32.08 -( More panoramic photography material ... )32.09 -( How to determine the aperture and f# of a lens? )32.10 -( Pointers for including the moon in a photograph )32.11 -( Sun and Moon rise/set locator program retrievable from Net )Select FAQ-33 to obtain content listed below
33.01 -( Starting points for using Konica and Kodak Infrared films )33.02 -( Intro to Gross Specimen and General Photography - tutorial )33.03 -( UK Company that makes microscope (and other?) adapers )33.04 -( Improvised Contrast Control filters from Rosco materials )33.05 -( Reducing overexposed IR film and others too )33.06 -( Tips for photographing the sun )33.07 -( Stage Photography Recommendations )33.08 -( Photographing Soccer Recommendations )33.09 -( Sprint Photographic Chemicals )33.10 -( Artcraft Chemicals - Photo Chemicals Supplier )33.11 -( A few non-US magazine recommendations )Select FAQ-34 to obtain content listed below
34.01 -( Accounting for extension tubes and exposure factors )34.02 -( Developing Tech Pan film recommendations )34.03 -( Managing Polaroid Type 55 Pos/Neg film in the field )34.04 -( Pinhole Resources and the Hole Thing )34.05 -( Multiple Exposure Capability - what good is it? )34.06 -( How are higher flash sync speeds achieved )34.07 -( Front projection for professional backgrounds )34.08 -( Desensitizing film for development by inspection )34.09 -( How much light does it take to expose film properly? )34.10 -( What is a diopter? )34.11 -( Daylight balanced fluorescent tubes and correction filters )34.12 -( How are the faster X sync speeds achieved these days? )34.13 -( How to adjust the tension on a Graflex Focal Plane shutter )34.14 -( How does a teleconverter change Depth of Field? )34.15 -( Title slides with BLUE backgrounds - how to make them? )Select FAQ-35 to obtain content listed below
35.01 -( Where to get photo jigsaw puzzles made )35.02 -( What to do with a camera that took a dip in the sea? )35.03 -( Russion Horizon(t) rotating lens panoramic cameras )35.04 -( How to expose, process and use Kodak Pro Copy film 4125 )35.05 -( Tips for Winning Photo Contests )35.06 -( Restoring faded photos by copying )35.07 -( Poop sheet on processing outdated Agfa Superpan Press )35.08 -( T-mounts, what are they? )35.09 -( Photography - the 8th art - article by Robert Fournier )file:///C|/faq.html (5 of 555) [7/19/2002 3:46:22 AM]
35.10 -( Developing stacks of prints simultaneously )35.11 -( Quick and easy "X" sync flash test for field use )35.12 -( How to compensate for exposure using extension tubes )Select FAQ-36 to obtain content listed below
36.01 -( How do Filters and Variable Contrast papers work? )36.02 -( Partial Stop Push/Pull Small Batch processing times )36.03 -( Memorable Photographs and Photographers - partial list )36.04 -( Photographing a total solar eclipse )36.05 -( Photo Mailer (envelopes to mail photos in) Supplier )36.06 -( Minox film supplier )36.07 -( Two comments on Pricing Weddings )36.08 -( Basics of Unsharp Masking - what it is and how to do it )36.09 -( Reversal Procesing of B&W Infrared Film for Speed and Slides)36.10 -( Pellicle mirrors in fast motor drive cameras - disadvantages? )36.11 -( Setting up a basic B&W darkroom with color possibility )Select FAQ-37 to obtain content listed below
37.01 -( Is Photography Finished? )37.02 -( Pointers on making image files for Web use )37.03 -( Further Notes on Polaroid Emulsion Transfer >
37.04 -( Where to get obsolete or hard-to-find lightbulbs in US )37.05 -( Where to have self-promotional postcards printed in US )37.06 -( Lens mount diameters / clearances for various cameras )37.07 -( Light trap overlap designs for darkroom access )37.08 -( Pointers for making a view camera from almost scratch )37.09 -( The Usenet rec.photo groups - how many are there? )37.10 -( Pointers for students seeking assistant's jobs )37.11 -( Bogen adapter for mercury battery using items )37.12 -( A personal approach to Reversal B&W Processing )37.13 -( Rodinal: Conversation, Observation and Formulation )37.14 -( Where to convert Nikon lenses to AIS mount? )37.15 -( Omega Enlargers - where to get parts? )37.16 -( More Pinhole camera tips - SPECIAL for TEACHERS! )Select FAQ-38 to obtain content listed below
38.01 -( Improvised IR filter and Wratten IR filter transmission data )38.02 -( Getting rid of green looking lights in night shots )38.03 -( Brief Basic Discussion on Film Speeds )38.04 -( Instructions Making a simple CLOSE-UP stand )38.05 -( 300mm lenses )38.06 -( Twin Lens Reflex Pros and Cons plus dealing with Parallax )38.07 -( Where to obtain bulk photographic chemicals )38.08 -( More Wedding Photography Tips for a beginner )38.09 -( Making an improvised densitometer from a light meter )38.10 -( Night photography shooting and exposure tips )38.11 -( E-Mail addresses within the RPS )Select FAQ-39 to obtain content listed below
39.01 -( Recommendation on Photo Journalism schools? )39.02 -( Brief description of Panoramic camera systems )39.03 -( Photographing of a whole train using a Cirkut camera )39.04 -( Where to catch romantic moods in Paris )-
file:///C|/faq.html (6 of 555) [7/19/2002 3:46:23 AM]
39.05 -( How do you make good pictures of reluctant models? )39.06 -( Is digital imaging art? Can it be art? )39.07 -( Comments on Electronic/Digital wedding/portrait proofs )39.08 -( How do focal length doublers/triplers work? )39.09 -( Developing film in sheet film tanks )39.10 -( Making reticulation and grain happen )39.11 -( Who makes 3D prints from Nimslo or Nishika negs? )39.12 -( Home made print washer instructions )39.13 -( Making positive B&W slides from B&W negatives )39.14 -( What is a good place to have light meters repaired? )39.15 -( 35mm film without perforations )Select FAQ-40 to obtain content listed below
40.01 -< A bibliography on Pinhole Books >40.02 -< Ethics at an accident or crime scene >40.03 -< A personal brown toner formulation >40.04 -< PJ Position Interviewing Advice - applicable elsewhere too! >40.05 -< Good Book recommendation - The Art of Photography >40.06 -< Putting pizzaz in a photography curriculum >40.07 -< Three Most Important Highlights in History of Photography >40.08 -< A couple more labs that process IR Ektachrome (E-4) >40.09 -< Hand Coloring - materials and instructions >40.10 -< Making your own bellows - instructions, supplies >Select FAQ-41 to obtain content listed below
41.01 -< Photography related quotations >41.02 -< How to make successful slides from prints >41.03 -< PPofA Certified Professional Photographer Exam Details >41.04 -< Listing the world's great living photographers (1996) >41.05 -< Mary Ellen Mark - brief history >41.06 -< Repairing/Cleaning a Schneider lens >41.07 -< Film expiration and storage tips >41.08 -< Making 3D pictures with ONE camera >41.09 -< Split development - what is it? >Select FAQ-42 to obtain content listed below
42.01 -< How to make a 620 camera take 120 film >42.02 -< Slide Labeling and Archiving Software for Stock Photos >42.03 -< Where do pros buy albums and frames >42.04 -< Star Tracking Platform instructions >42.05 -< Processing Forte B&W films in Kodak developers >42.06 -< Determining lens focal length simply >42.07 -< Where can one get royalty-free background music? >42.08 -< Robot camera company address >42.09 -< Split Grade Printing by Max Ferguson >42.10 -< Guide Number when flashes are combined >42.11 -< Some places that process Super-8 motion picture film >42.12 -< Bulkfilm loading without a loader >42.13 -< How do flashbulbs work? >42.14 -< Tripod Tips >42.15 -< Some chit chat on camera lenses used for UV photography >Select FAQ-43 to obtain content listed below
file:///C|/faq.html (7 of 555) [7/19/2002 3:46:23 AM]
43.01 -< Instructions for using a Gossen Luna Pro F light meter >43.02 -< On Taking Yourself Seriously by David Vestal >43.03 -< MacGyverish tools used by photographers >43.04 -< How to make Public Relations photographs at school >43.05 -< How to compensate for use of "minus" diopter lenses? >43.06 -< Instructions for making one's own print washer >43.07 -< Processing FORTE film in Kodak developers >43.08 -< Determination of actual focal length of view camera lenses >43.09 -< Are obsolete flashbulbs available anywhere? >43.10 -< Another go at Film Acceleration >43.11 -< Developing in ascorbic acid - tips and hints >43.12 -< D-25 developer >Select FAQ-44 to obtain content listed below
44.01 -< Color Correction Conundrum >44.02 -< Removing Dye Layers from Color Film One at a Time >44.03 -< What is the actual f stop given by lightmeters? >44.04 -< The Arnold Gassan Method for HC-110 >44.05 -< Photos of your "aura" ... Kirlian Photography >44.06 -< How to expose Night Scenes properly, a guide >44.07 -< Removing Scratches from lenses ... regrinding surface? >44.08 -< Shooting digital or scanning film, which is better? >44.09 -< Split Toning advice >44.10 -< Photographing (shooting) with a steady hand, how? >Select FAQ-45 to obtain content listed below
45.01 -< The "Color Wheel" and RGB/CMY >45.02 -< Cameras for school use to replace the K1000 >45.03 -< The Business of Youth Sports / Teams Photography >45.04 -< Speaking engagement about photography and careers >45.05 -< Advice for a Figure Study Photo Workshop >45.06 -< Suggestions for Content of a Portfolio for Transfer Credit >45.07 -< Some chit chat on Fundamental Principles in Polarization >45.08 -< Panoramic Stitching Software - PTStitcher >45.09 -< Flashbulbs NOT a lost art yet >45.10 -< Fake Ice Cubes for studio prop >45.11 -< Polaroid Emulsion Lift-off Prints, short instructions >45.12 -< Finding the F number - instructions >45.13 -< Guide Numbers with multiple flashes - how? >45.14 -< Getting started with Volunteer Photo Teaching >-
================================================================================
Note 15.01
-< Make Slides from Negatives using Kodak SO-279 >-------------------------------------------------------------------------------SLIDES FROM NEGATIVES USING SO-279, Vericolor Slide Film a negative working
copy film designed without orange mask for making slides from color negatives.
From:
Subj:
IN%"[email protected]" 23-FEB-1993 01:13:48.62
RE: More questions...SO-279, or slides from negatives
I have a lot of color negatives I'd like to turn into slides, so naturally my
file:///C|/faq.html (8 of 555) [7/19/2002 3:46:23 AM]
attention turned towards Kodak's Vericolor Slide Film SO-279. I noticed you
posted the following on rec.photo and wonder if you could assist further.
>
>
>
>
>
>
If you already own a color enlarger then it may be possible to convert it to
serve as a light source for a copying set-up. Once I bought a color head for a
35mm Durst enlarger from Helix in Chicago for about $ 25 or 40 (don't recall
exact price... they were "dumping" them due to overstock) and this has served
the purpose of adjusting the color quality of the copies very well.
This is possibly cheaper and more flexible than buying a set of CC filters.
I need some advice, if I may not be troubling you too much..
I have a cheap enlarger(accepts color filters though it's a B&W). So I think I
can manage to convert it to a decent light source. I also have a Canon EOS Elan
28-70 II lens & a good tripod. What else do I need to make slide/neg duplicates?
I guess another lens to get into 1:1 macro range? How do I proceed to make
duplicates? - how do I make sure that the slide/neg is exactly in the centre &
is perfectly parallel to the film plane?? Thanks in advance..
Jay
email : [email protected]
..................................
From:
To:
Subj:
reply
...................................
RITVAX::ANDPPH
23-FEB-1993 22:48:40.09
IN%"[email protected]"
RE: More questions...SO-279, or slides from negatives
...actually if you have the enlarger you already have the appropriate lens. The
one that is fitted to the enlarger! It will generally do quite well. You should
be able to project the image into the Elan (remove the lens you have on it now)
and see a pretty bright image on your viewfinder screen. Depending on enlarger
you may be able to the enlarger so it is aimed horizontally instead of
vertically (if possible reverse head orientation on post and use baseboard to
kind of hold enlarger steady) and then mounting camera on tripod position at
right distance for about 1:1 magnification.
If the lens can not be moved far enough from negative and lens has a Leica
thread, (most enlargers do) get a short Leica extension tube and attach lens to
it to get extra extension.
The Elan can probably be set to give you automatic exposure time control based
on a "stopped down" metering mode. You simply need to work out what effective
exposure index you would key into the camera for the speed of the Vericolor
Slide film you will be using. This typically is about ISO 6 or so. Pretty slow!
>How do I proceed to make dulicates? - how do I make sure that the slide/neg is
>exactly in the centre & is perfectly parallel to the film plane??
Well, "perfectly" is questionable. Approximately often will work just as well
and you will have to use some ingenuity here. Since you can see the image on
the groundglass (in the viewfinder) if the image is sharp side to side you have
things pretty much under control. Using a slightly smaller than margest opening
will help with sharpness but shape may be a bit (probably not noticeable
anyway) off.
file:///C|/faq.html (9 of 555) [7/19/2002 3:46:23 AM]
To make duplicates you insert the approximate filter pack made up with
recommended Color Compensating (located between copy film and original film) or
Color Printing (located between light source and original film) filters
according to manufacturer's recommendations. If none given I'd start with about
40Y and 20M and an ISO in camera of as low as possible. Then I'd run a series
of exposure variations goving less than recommended exposure in 1 stop
increments BUT ALSO a series where the exposure is even longer than the time
suggested by the meter at that ISO. May have to do these things manually.
Keeping good notes is essential. After processing and having film returned
uncut so frame identification is simplified I'd go looking for a slide that has
good density. Once this is accomplished then I'd go looking for proper color as
well. If this does not exist then I'd take the best slide in terms of density
and then make another test at that "exposure" level but change the filters in
such a manner as to correct the color balance of the resulting slide.
If the slides are too red, the add red to the basic filter pack, if too blue
add blue (or cyan and magenta together), if too magenta add magenta. This is
like color printing except that you end up with transparent prints!
hope this helps,
andy
From:
To:
Subj:
IN%"[email protected]" 25-FEB-1993 18:38:36.01
IN%"[email protected]"
RE: More questions...SO-279, or slides from negatives
Fantastic!!
Your reply was very useful & it works!!!
Thanks a lot! I could have never guessed that I don't need any more equipment!
Thank you again..
Jay
================================================================================
Note 15.02
-< What is Angle of View of any Lens on any Camera? >-------------------------------------------------------------------------------I'd like to know whether there exists a formula (or second best, a conversion
table) for calculating the angle of view given a focal length, and vice versa
(e.g. given a 300mm lens, 8.1 degrees is correct....I think)
The formula is:
The angle of view for any given film dimension is equal to 2 times the angle
whose tangent is equal to the film dimension in question divided by 2 times the
focal length.
this is for a non-distorting lens that is a "regular" lens not a fisheye.
let's see
-1 / film dimension\
|---------------|
\
2 f
/
< of view = < tan
43
-------- = .071
2 x 300
angle whose tan = .071 = 4.09 x 2 = 8.18
file:///C|/faq.html (10 of 555) [7/19/2002 3:46:23 AM]
pretty close, eh?
BTW, 35 mm format dimensions are 24mm x 36mm and the diagonal is 43mm (or 44).
================================================================================
Note 15.03
-< Color Crossover, Color Conversion and Temperature >-------------------------------------------------------------------------------THIS IS A DISCUSSION FROM PHOTO-L ON THE TOPIC OF COLOR CROSSOVER and COLOR
TEMPERATURE AND COLOR CONVERSION FILTERS TO MATCH FILM TO LIGHT SOURCES
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Is there anyone out there that can explain to me better than an average
textbook the meaning of "color crossover" as a result of reciprocity
failure of color film. I know that there is a color cast, and that the
color in the highlights somehow becomes the color of the shadows, and I
know that contrast is affected, but I really am not 100% clear on the whole
thing.
From: [email protected]
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Subj:
RE:
Color CrossOver
I'll make a pass at explaining color crossover, assuming that by 'better'
you mean simpler, easier to understand, etc.
Basically, all color films are designed such that there are three emulsion
layers sensitive to three complimentary light colors (red, green & blue;
or cyan, yellow & magenta). One notable exception is Fuji Reala, which has
four emulsions, but don't worry about Reala for the moment. Ideally, the
three emulsion layers should all be insensitive to light outside their
prescribed color range, but nothing's perfect. The erroneous exposure
resulting from this imperfection is called color crossover. In other words,
the red layer reacts to some blue and/or green light, the green layer reacts
to red and/or blue, and so on. Really bad color crossover is a color printer's
worst nightmare. You'll wind up making test print after test print, adjusting
color in all directions and never get an entirely satisfactory
print. Of course, in extreme long exposure resulting in crossover, maybe
the weird color is what you want for an artistic effect.
Steve Wall
From: SFAE-AR-HIP-SY Stephen Wall <[email protected]>
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>Is there anyone out there that can explain to me better than an average
>textbook the meaning of "color crossover" as a result of reciprocity
>failure of color film.
file:///C|/faq.html (11 of 555) [7/19/2002 3:46:23 AM]
Well, after I composed my reply appended below I reread your plea for "better
than the average _textbook_" and on looking at the stuff I put together it
looks like your average textbook reply, so now I am not sure..... :-)
This is what I understand cross-over means when talking about color systems.
Shadows
Highlights
*+*.+*+.
CASE 1
*+.
*+.
*+.
*+.
*+.
*+.
*+.
*+.
*+.
*+.
*+.
^
|
D
E
N
S
I
T
Y
Desired Outcome. No color casts.
Response of the three color layers
is superimposed on each other
*, +, .
= color layers
*+.*+.*+.
Log Exposure --->
*+*.+ +.
*
+.
*
+.
*
+.
*
+.
*
+.
*
+.
*
+.
*
+.
*
+.
*
+.
*
+.
* *+.*+.*+.
CASE 2
One layer is slower than the rest
but has the same contrast as the others
A color cast will be shown everywhere
With negative color films this can be
compensated for at the printing stage.
(curves for neg materials are reversed)
With transparency materials this can be
compensated for at the taking stage and
partially at the viewing stage
Cause of something like this could be shooting under incorrect lighting, using
a filter on the camera, age, maybe processing, maybe reciprocity effect.
*+.*+.
+.
+.
*
*
+.
+.
*
+.
* +.
* +.
*+.
*+.
*+.
+.*
+.
CASE 3
One layer has different contrast than the rest
causing its its curve to "cross over" in
the midtone regions. Actually, cross-over does
not need to happen in midtones... it could
happen anywhere. In this case it is evidenced
by a color cast showing in the shadows and a
complementary color cast on the highlights
*
+.
*
+. +. +.*+.*+.
file:///C|/faq.html (12 of 555) [7/19/2002 3:46:23 AM]
Cause of something like this could be processing error, reciprocity failure,
storage effect, or celestial intervention.
This is an introductory attempt at trying to answer the question about
cross-over. I decided to post this in hopes that I would get some follow up
help in terms of verbal descriptions to go along with these pictorial
representations since at this time I do not have the time to go much beyond
this. I look forward to critiques and additional comments. Have fun!
From: "Andrew Davidhazy" <[email protected]>
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Subject: Color Conversion Problem
I left a message a while back regarding filters needed while shooting outdoor f
ilm under tungsten lights (100 Watt). Why would i need to use a 82b aND 80a fil
ter, and not just a 82b?
Wayne
From: RSIU42G%[email protected]
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Subj:
Color Conversion Question
Hi Wayne, re: your question on color conversion this prompted me to look into
Kodak's B-3 book on Filters for Scientific and Technical uses.
What I found is that the 100 watt lamp burns at about 2900 K and you want
to convert this to 5500 K. If each of these is assigned it's appropriate Mired
value, then you want to go from about 345 to 182 or a total shift of - 163
mireds. A Mired is simply the K value divided into 1,000,000, but this is
another story...
The 80A filter has a "power"of - 131 mireds which is not good enough. You need
some more blue ( which is what the " - " sign implies ) to the extent of
another - 32 mireds. This is supplied by the 82B.
You could use other filters for similar results. A 80B plus a 80D is close at
168 mireds. Two 80C filters are also very close at 162 mireds.
Another way to say all this would be that the 80A gets you from 3200 to 5500 K
but you first need to get from 2900 to 3200 and this is done with the 82B.
There is no single filter listed by Kodak that provides 2900 to 5500 correction
in one step.
BTW, the price for doing this is almost 3 stops. It is much more efficient to
use indoor balanced film outdoors than the other way around.
From: "Andrew Davidhazy" <[email protected]>
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
file:///C|/faq.html (13 of 555) [7/19/2002 3:46:23 AM]
Subj:
Tungsten Lamp filtration
>I left a message a while back regarding filters needed while
>shooting outdoor film under tungsten lights (100 Watt). Why would i
>need to use a 82b aND 80a filter, and not just a 82b?
>Wayne
Wayne, the real determining factor is not the wattage of the
lamps, but their color temperature, as expressed in degrees Kelvin (or
just K). I regularly shoot under tungstun (quatrz halogen) lamps with
an 80B filter and get very good results. Assuming you do not have
access to a color temperature meter (I don't), then your best bet is
to find what the manufacturer rates your lamps at for color temp, and
filter accordingly. The other question is `how accurate does the final
color need to be'? I use both 3200K and 3400K lamps, sometimes mixed,
when shooting people, and get very good results for skintone (which is
my benchmark). On the other hand when shooting art pieces for artists,
we keep the color temp as consistant as possibile, and filter much
closer, many times doing test rolls.
brucer
From: "Bruce T. Ritchie, P.S.C." <[email protected]>
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Subj:
filters
What book did you use as a reference? Is it possible to get the title, author
and ISBN number off you?
I am presuming that if I just used one of the filters and a outdoor film the
shots would have been yellow, right?
Wayne
From: wayne <RSIU42G%[email protected]>
Organization: King Fahd University of Petroleum and Minerals, S.A.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Wayne,
The Kodak book I used is their Publication B-3, Kodak Filters for Scientific
and Technical Uses, Kodak Cat 152 8108. It has a ISBN # of 0-87985-282-8.
You may be able to obtain a copy from Kodak by calling their Hot Line @
1-800-242-2424. The copy I have has a price of $ 11.95 printed on it but the
book is a few years old.
A fairly comprehensive technical reference or textbook on technical questions
is Materials and Processes of Photography by Stroebel, Compton, Zakia and
Current published by Focal Press. Or their Basic Photographic Materials and
Processes.
file:///C|/faq.html (14 of 555) [7/19/2002 3:46:23 AM]
let me know if I can be of further assistance, andy
From: "Andrew Davidhazy" <[email protected]>
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Subj:
filters
Are 3200K and 3500K standard light temperatures used in studio situations? Why
not use 5500K bulbs, wouldn't that give a light source that is more white? I
can see that a slightly yellow (ie. using only one of the 80A and 82B filter
sets for 100 Watt tungsten bulbs) could enhance skin tones, but could you not
get a similar effect by diffusing a white light. This would reduce the
bleaching effect of the whiter light source.
And now for something completely different (Where did I hear that before?)
Have you ever shot sky (blue) with Ektar 25? I have been finding that the
higher from the horizon you aim, the deeper the blue is. Also polarization does
not seem as drastic as with other films such as Kodacolor gold 100 or
Ectachrome 100. My skies are comming out baby blue with a polarizer and a very
pale blue without. Any comments?
Wayne
From: wayne <RSIU42G%[email protected]>
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Wayne,
Yes, with only one of the two filters the pictures would turn out on the
yellow side. The 80A does most of the correcting. The 82B is a very pale blue.
The problem with not making tungsten bulbs so they operate at daylight color
temperatures is that the filaments would not last. Manufacturers do make 5500 K
balanced photofloods by incorporating a pale blue filter on the coating of the
bulb. This allows you to use these floods while also having daylight present in
the scene. Using filters on the camera would preclude mixing the two light
sources.
... also, the standards for color temperature of photofloods are 3200 and 3400
degrees Kelvin. also, BTW, if you use color negative film typically color
conversion filters are not needed, only for transparency films that can not be
corrected at the printing stage. But you probably already knew this...
andy
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Subj:
filters for tungsten
Wayne (and anyone else out there who is interested...just covering my tracks.:-)
file:///C|/faq.html (15 of 555) [7/19/2002 3:46:23 AM]
If you consult your friendly Koday Professional Photograpy guide (publication
#R-28 latest revision) you will find a handy device called a "color temperature
balance dial" which gives you the filtration for various light
sources depending on film used, and, yes, with a 100 watt domestic tungsten
bulb you need 80A+82B for daylight film...
Why? you ask..simple, because daylight film is balanced for 5500 kelvins,
and 100 watt bulbs emit a color temp of about 2900 K. NOw, photo lights
intended for tungsten type L film (the one most used with hot lights) emit
at about 3200 K which is what the 80A filter is designed to convert to daylight
balance....hence, you need a bit more blue for the 100 watt bulb to
compensate for the extra 300 degree shift, and an 82B in combination
with an 80A does the trick.
brian
From: Brian Segal <[email protected]>
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Subj:
daylight photo bulbs
Daylight filtered photo bulbs are not very accurate or consistent, and they
have a short working life...I used them for a while and was constantly
disappointed with the color results.
The best course of action, of course, is to (A) use a color meter to
color filtration and (B) shoot a test roll if accuracy is important.
Color meters have lots of interesting applications..for instance you can
purposely bias your image by entering either a too blue or too yellow
temp into the meter's memory and then it will tell you what filters to
use for the desired effest under varying light conditions.
In that way, you will affect the color balance of your film.
You really notice the benifits of color metering and filtration when shooting
under overcast skies or at mid-day when there is lots of blue bias
in the environment. SHots that would normally be kind of cold and washed out
become full of color and life when tweaked with some 81 series and magenta fil
filters in combo..
brian
From: Brian Segal <[email protected]>
================================================================================
Note 15.04
-< 5 vs. 7 sprocket format stereo cameras >-------------------------------------------------------------------------------Subj:
RE: sprocket question in 3D photography
> What is meant when you talk about 5 sprocket or 7 sprocket film in reference
> to stereo photography?
file:///C|/faq.html (16 of 555) [7/19/2002 3:46:23 AM]
The distance between two sprockets (or perforation-holes) is 4.750 +- 0.013 mm
or 0.1870 +-0.0005 inches (according to ASA Standard Z22.36-1947).
So the 5 sprocket format means stereo images that are 23.75mm wide (e.g. those
taken with the Stereo Realist: format 24 x 23 mm (the extra .75mm is needed
as a separation between the pictures).
The 7 sprocket format (33.25mm) is also called the 24 x 30 mm format and is
used by the FED, the Belplasca and the Verascope F40.
From: Alexander Klein, Stuttgart, Germany, [email protected]
================================================================================
Note 15.05
-< Several observations about Kodak B&W IR film >-------------------------------------------------------------------------------Several personal observations about Kodak IR B&W film:
1. It does not have an antihalation backing. This allows light + IR piping into
cassette and also promotes halation in the vicinity of overexposed areas.
2. The film can be loaded/unloaded from camera in subdued lighting especially
if the light is poor in IR content such as that from fluorescent bulbs.
I think the reason the Kodak suggests total darkness is that they can obviously
not predict what any given person will interpret as "subdued" so they just say
"total" and are thus covered. Exposure, even fogging exposure, being time as
well as intensity dependent, would also indicate that one would want to keep
the exposure to even "subdued" light as short as possible.
3. Use with a red filter sort of negates some of the reasons that you'd want to
use this film as it will record red along with the IR record.
4. Use with 87, 87C or other truly IR filter limits you to static subjects or
use of a rangefinder or twin lens reflex camera or use of an auxiliary finder
if used on a SLR camera .... unless...
5. you place the 87C or such filter between the mirror of your SLR and the film
plane. This can be easily accomplished by cutting a piece of filter that is
about 23.5mm x 45mm in size and placing it between the film plane guide rails
that the film travel over. There is plenty of room for the thin gelatin filter
to sit there held in place by equally thin pieces of Scotch translucent tape at
each end.
alternatively, a larger piece can be placed carefully in front of the shutter
but behind the mirror. Do this only with cameras that do not have OTF metering
systems. Note: do either at you own risk. I never had a problem but can not be
responsible for someone's finger going through their shutter! :-)
5. Some light meters can be calibrated to read IR in such a manner that their
indications will yield closer to correct exposure than simple guesses.
6. If you are going to calibrate a meter to read IR through a 88, 87 or 87C
file:///C|/faq.html (17 of 555) [7/19/2002 3:46:23 AM]
filter then make sure you use it in the reflected metering mode as incident
readings in IR mean very little since you do not know the inherent IR
reflectivity of the subject.
7. IR film does not need extreme care in handling but it should be similar to
what you would give color film that is about to or which contains irreplaceable
images. Extra care is warranted but the film is not going to fall apart on you
as long as you take reasonable care with it.
8. Because IR film is quite transparent to IR (as well as visible) you may find
an overall regular pattern of spots all over your film. If you do check your
camera's pressure plate. It probably also has a similar set of "dimples" on its
surface. The IR is collected by these and focused back onto the IR film
producing a reproduction of the dimpled pattern onto the film.
9. If you use IR film in dark situations you can place an IR filter over your
flash and take flash pictures with the flash becoming unobtrusive. Probably you
will not want to use an IR filter over your lens at the same time if doing
"candid" flash photography. Skin tones will, however, be reproduced rather a
lighter tone than on regular film because of the high IR reflectance of skin,
any skin. Thus persons with rather dark complexion will appear as light in tone
as those of lighter complexion.
10. If you do not want to buy a large IR filter to use over your flash, you can
improvise by using a sheet of developed but unexposed color film such a
Ektachrome or Fujichrome. Even though the film appears absolutely black it
transmits IR quite freely.
well, that 10 is observations. That is enough for today. Got to go shovel.
andy
================================================================================
Note 15.06
-< Precision Pinhole Parts for Pinhole Photographers >-------------------------------------------------------------------------------Do you need precision pinholes and plans for your pinhole camera?
Read on.
I now have precision pinholes in brass which have been laser diffraction tested
for size and uniformity. Prices are $5.00 for one, $7.50 for two or $10.00 for
three. Matched sets (+/- 1/4 f-stop) are available for panoramic pinhole
cameras. Prices include plans for three pinhole cameras including a panoramic
one. The panoramic camera can use three or more pinholes. Add $2.00 for each
additional pinhole over three.
Large quantities available for photography classes. Send email requesting info
on the quantity you need. Pinholes come with data stating hole size so you can
make preliminary f-stop approximation and all instructions. Send orders to:
Jim Michael, Box 941124, Atlanta, GA 30341
e-mail: [email protected]
- this was posted on rec.photo on the Internet Netnews -
================================================================================
Note 15.07
-< Reversal Processing of Black and White paper >-------------------------------------------------------------------------------file:///C|/faq.html (18 of 555) [7/19/2002 3:46:23 AM]
PROCESSING ENLARGING PAPER AS A POSITIVE
...means you can use the paper in a camera and make one-of-a-kind images...
...roughly collected from info seen in various rec.photo postings...
If you use the paper as a material in the camera then you may wish to consider
using Panalure for "normal" looking results in terms of tonal reproduction.
This is becasue normal B&W papers are not sensitive to red and thus anything
colored red in a scene will turn out very dark or black.
You can also make B&W prints directly from slides this way. Place a slide in
the enlarger and project it onto B&W paper. Again, to maintain more natural
looking tones use Panalure.
The chemicals and processing steps are as follows:
First Developer
Rinse
Bleach R-9
Rinse
Clear CB-1
Rinse
Expose to light
Second Developer
Fix
Wash
Dry
60-90 seconds
30 seconds
30-60 seconds
30 seconds
30 seconds
30 seconds
40 W bulb for 5-10 seconds at 12 inches
30-60 seconds
30-60 seconds
Normal paper washing time
First Developer: The original literature referring to this method of making
positive prints from slides is Kodak Publication G-14, "Direct Positive
Photography". You can probably get a copy of it by calling the Kodak Hot Line
at 800-242-2424. In any case, that booklet specified a high contrast developer
such as D-88. Dektol or D-72 dilited 1:1 can probably be substituted
successfully for D-88.
Rinses should be under running water, or at least two changes in the 30
seconds.
The bleach is modified Kodak Bleach R-9:
Water
Potassium Dichromate
Sodium Bisulfate
Water to make
800
9.5
66
1
mL
g
g
L
Clear CB-1:
Sodium Sulfite
Water to make
90 g
1 L
Second Developer can be Dektol again. Or if you want a sepia toned print,
skip the light exposure and use Sulfide Redeveloper T-19 (Sodium Sulfide
20 g with water to make 1 L).
file:///C|/faq.html (19 of 555) [7/19/2002 3:46:23 AM]
As with any positive process, the resultant density value is opposite from
ordinarily processed paper: More exposure = lighter print, less exposure
= darker print.
================================================================================
Note 15.08
-< Making POLAROID Color Transfer Prints >-------------------------------------------------------------------------------Here's the scoop on the transfer process.
For Polarid info call Polaroid Technical Assistance Hotline
800/225-1618
There's also a booklet available: Professional Guide to Image Transfer Polaroid
films: Any peel apart color material
no SX-70's and no B/W or Time Zero.
Substrates: Hot press watercolor paper, Cold press watercolor paper, Rice paper
Other (wood, leather, cotton, silk)
1. Prep the watercolor paper or surface you'll make the transfer onto. Soak
paper's in distilled water that's warm to the touch. Some folks use a bit of
photo flo in the water and other's use sodium bicarbonate to raise the pH. Wet
materials work better than dry one's. I've had good luck with soaking rice
paper's in room temp. distilled water, blotting it between layers of paper
towels and then putting it on a small piece of wood, a stage if you will, that
those nasty 'Roid chemicals can touch etc. For some odd reason the wood which
is about 1/4" thick and 5x7" is just right for the transfers and handy to pick
up and hold under a light, move around etc. while you're making a transfer.
2. Make an image on the Polaroid film. This can either be done with a 4 X 5 or
8 X 10 Polaroid back or by taking a 35mm slide and making a Polaroid print by
using a Vivitar Slide Printer.
3. Pull the Polaroid through the rollers to pop the chemical pod and coat the
negative. Approximate processing times are 10-15 seconds. Then peel the
Polaroid "print" or receiver sheet from the negative. I'm going with 10 sec.
times for images that have large amounts of red in them, longer times for
cooler images.
4. Gently put the negative in contact with the wet paper you've prepped. Roll
the top of the neg. with something akin to an ink roller for good contact. Some
folks use a press, their hands or a brick for this. Turn the paper & negative
over and gently rub the back of the paper with your fingers as if pressing out
an air bubble. Fastest transfer time would be around 90 seconds and the longest
times run around 30-40 minutes. The Average transfer time's recommended by
Polaroid are 2-5 minutes. Two minutes is working just great for me.
5. Very slowly and gently peel the negative off of the paper. Use the tab to
pull with and keep the neg. almost parallel to the paper. If you're losing
blacks or shadows that's image lifting and you're pulling too fast.
6. Step back and admire the darn thing! At this point you could send it to a
printer for separations, let it dry and use if for a display print or add other
elements to the image with pastels, colored pencils, dye's, chalk, oils etc., I
mean hey... it's a piece of paper right ?
file:///C|/faq.html (20 of 555) [7/19/2002 3:46:23 AM]
I saw some very good results done with a Vivitar slide printer (print size
about 3X4), both with color E-6 materials & PolaPan B/W and Polachrome self
processing 35mm films. The slide copier also accepts filters so that you can
change many things with that feature as well. (ie, up the red content since
red's don't transfer all that well) The rep. I talked to on the phone said that
he got better results with hot press watercolor paper. A cold press paper will
have a texture to it and can be difficult to use when you're first trying it
all out, but then again the same texture can add another element to your image.
I've had great luck using rice papers. My local source sells a *very wide*
variety and ships everywhere. You might give 'em a call and ask for a catalog.
" Dan Smith Inc. " Orders: 800/426.6740 Cust. Service: 800/426.7923
They might have an Oriental Paper Sampler, just ask. These folks have large
sheets of rice paper with leaf's, butterflie's in them. The range of papers is
amazing, they even carry papyrus. When you're on the phone with them ask if
they know of thier counterpart in your neck of the woods. Reason being that you
should find a table with paper thats been "damaged" in transit and sold at a
good discount. A goofed up corner on a 30x42" sheet really doesn't matter all
that much for 'Roid transfers if you're cutting it up anyway.
I've found a great paper that's about $7 for a sheet thats around 1 sq. foot in
size. So when working with a new image I use a cheaper paper, thinner and cut
from a larger sheet to make my proofs on. The thin paper dries out in 30 min.,
one time when I was in a hurry I was nuking the transfers and they looked just
fine.
Polaroid also makes a slide copier that projects a 35mm frame onto an 8 X 10
sheet of Polaroid film (the Polaprinter). It's a rather large desktop unit. Of
course you'll also need the desktop processor for the 8 X 10's. The list price
for the Polaprinter is $1,629.90 (street price under $1K) and the Vivitar one
lists for $160.00 but is available from your local dealer at a more reasonable
price. ($115-125.00) Or from DAK for about $60.00 The image transfer process
has become so popular that Polaroid is now selling a starter kit which consists
of a tray, rubber roller and a pack of film. It lists for $39.34
Talking to the rep. on the hotline I was told that to keep an image archival
you need to either re-photograph it or get color separations made. Because
there are so many variables in different stages that everyone uses it's almost
impossible for them to even start advanced ageing research.i.e. Boston tap
water is the best, NYC water is the best ... ink rollers are best, bricks are
best, long vs. short times.
Have a blast!
Don
Don Smith Photography [email protected]>
............................................................................
From _Test_ Polaroid's magazine for professionals.
"
Photographer: Myron's techniques "underexpose transparency 1/2 stop for better
color saturation and to avoid contrast problems.orange & red will transfer to
the Polaroid receiver sheet first, therefore the short process time.soak
watercolor paper, squeegee it and then give a half an hour to dry. Paper that's
too wet causes bleeding of colors.transfer times of 30 to 90 minutes depending
file:///C|/faq.html (21 of 555) [7/19/2002 3:46:23 AM]
on color range in the original and type of paper you're using.loss of blacks
indicates too fast a pull of the negative from the paper.Myron air dries the
paper which then buckles, he mists it with some water and then puts it into a
hot dry mount press for about 30 seconds. Then flattens them with a weight.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
From: IN%"PHOTO-L%[email protected]" "Photography Phorum"
Date: 10-JUL-1992
Subj: RE: polaroid transfers
Brian
Here are ten good tips for making Polaroid transfer prints.
1. Select a receptor sheet that will help you get the type of results you want.
The tooth of the paper has a big role in the image quality.
2. Be careful to eliminate excess water from the receptor sheet.
If the receptor sheet is too wet, excess developer will remain on the
transferred image, causing the dyes to liquify and run.
3. As a rule, the sooner you peel the film, the better the colors.
10 seconds is the optimum development time. Pulling any sooner than that
the dyes might not have had enough time to begin migration. Pulling later
than that, the migration of dyes will alter the color balance of the image.
After about ten seconds, the negative has almost all of the cyan dye, about
half of the magenta dye, and very little of the yellow dye.
why most transfers have a cyan bias.
This explains
To correct, use between 10cc and 20cc
red filtration.
4. Press the negative against the receptor sheet evenly.
In areas where the pressure wasn't applied evenly, the emulsion may peel
awaymore easily.
5. Soft rollers work better than rough ones.
6. When rolling your image, don't press too hard.
IF you use too much pressure, the image will not stick well to the receptor
sheet. For best results, start at one end and roll smoothly, with even
and moderate pressure.
7. Peel the negative away slowly.
This is to help prevent tearing of the emulsion.
8. Manipulation of colors is easiest done by using filters during exposure.
Watercolors are great for spotting too.
9. Storage of film should be around 70F with normal humidity.
Adverse conditions can affect transfer capabilities of the film.
10.Clean camera roller routinely.
file:///C|/faq.html (22 of 555) [7/19/2002 3:46:23 AM]
Shmutz on the rollers will show up on the transfers. Also, becareful
not to scratch the rollers as the scratches will show up too.
Some other ideas possible transfer problems:
Water ph has an effect on transfers. Images do not adhere as well with water
of low ph. For best results, water ph should be sesven or higher. When in
doubt, use distilled water for consistent results.
Make sure that you soak the receptor sheet well.
to squeegee as much excess water as possible.
After soaking, make sure
Don't wait too long before placing the negative on the receptor sheet.
dyes will dry out and affect transfer and adhesion.
The
After rolling the sandwiched negative and receptor sheet, wait between 90sec
and two minutes before peeling the negative away.
troyb
From: HELLO <[email protected]>
================================================================================
Note 15.09
-<Sample Model Release>-------------------------------------------------------------------------------... sample model release FYI and consideration:
ADULT RELEASE
In consideration of my engagement as a model, and for other good
and valuable consideration herein acknowledged as received, I
hereby grant to <photographer> ("Photographer"), his/her heirs, legal
representatives and assigns, those for whom Photographer is acting,
and those acting with her/his authority and permission, the irrevocable
and unrestricted right and permission to copyright, in his/her own name
or otherwise, and use, re-use, publish, and re-publish photographic
portraits or pictures of me or in which I may be included, in whole
or in part, or composite or distorted in character form, without
restriction as to the changes or alteration, in conjunction with my
own or a fictitious name, or reproductions thereof in color or
otherwise, made through any medium at her/his studios or elsewhere, and
in any and all media now or hereafter known for illustration,
promotion, art, editorial, advertising, trade, or any other purpose
whatsoever. I also consent to the use of any printed matter in
conjunction therewith.
I hereby waive any right that I may have to inspect or approve
the finished product or products and the advertising copy or other
matter that may be used in connection therewith or the use to which
it may be applied.
I hereby release, discharge and agree to save harmless
Photographer, his/her heirs, legal representatives and assigns, and all
the persons acting under his permission or authority or those for
file:///C|/faq.html (23 of 555) [7/19/2002 3:46:23 AM]
whom he/she is acting from liability by virtue or any blurring,
distortion, alteration, optical illusion, or use in composite form,
whether intentional or otherwise, that may occur or be produced in
the taking of said picture or in any subsequent processing thereof,
as well as any publication thereof, including without limitation
any claims for libel or invasion of privacy.
I hereby warrant that I am of full age and have the right to
contract in my own name. I have read the above authorization,
release, and agreement, prior to its execution, and I am fully
familiar with the contents thereof. This release shall be binding
upon me and my heirs, legal representatives, and assigns.
Name:
Date:
Address
phone:
Signature:
Note 16.01
-< More Model Releases >-------------------------------------------------------------------------------Always get the release before the shoot. At that point the model is more
willing to sign.
If he/she will not sign or is troubled by any of
the wording a compromise can be reached. Modifications can be made to
the release, just draw a line through the offending sentance/paragraph,
both parties initial by the correction and all is legal.
Some releases, like the one in question, most of the ASMP releases and
many others are very wordy. They may frighten simple folk like you or
me. The release shown below is from a very good book on the business
of photography. It is good but with an emphasis on simple. The book
is "Big Bucks," by Cliff Hollenbeck. Cliff is a travel/location/and
advertising photographer located in Seattle Washington. He is well
known in the business and is an ASMP member. He has been included in 3
"day in the life" books. His Release...
PHOTO RELEASE
I give (your name) permission to photograph myself and/or property,
and to use or sell the materials as he/she whishes.
_______________________________________
Signed
_______________________________________
file:///C|/faq.html (24 of 555) [7/19/2002 3:46:23 AM]
Name (Print)
_______________________________________
Address
_______________________________________
City
State
_______________________________________
Zip Code
Date
MINOR PHOTO RELEASE
I give (Your Name) permission to photograph
the below named minor, and to use or sell the materials as he/she
wishes.
__________________________________________
Signed
(Parent/Guardian)
__________________________________________
Minor's Name
Age
__________________________________________
Address
__________________________________________
City
State
__________________________________________
Zip Code
Date
...............................................................................
and another one:
PHOTOGRAPHER'S MODEL RELEASE - (long form)
For a consideration mutually agreed upon and received by me for posing, I
hereby irrevocably consent to and authorize the use and reproduction of all
photographs and/or slides, and in consideration of my engagement as a model
by___________________________ , hereafter referred to as the photographer,
on terms or fee hereinafter stated, I hereby give the photographer or his
representatives, those for whom the photographer is acting, and those acting
with his permission, or his employees, the right and permission to copyright
and/or use, reuse and/or publish, and republish photographic pictures or
portraits of me, or in which I may be displayed in character, or form, either
wholly or in part, on reproductions thereof in color or black and white made
through any media by the photographer at his studio or elsewhere, for any
purpose whatsoever, including the use of any printed matter in conjunction
therewith.
I hereby waive any right to inspect or approve the finished photographs/slides
or advertising copy or printed matter that may be used in conjunction therewith
file:///C|/faq.html (25 of 555) [7/19/2002 3:46:23 AM]
or to the eventual use that it might be applied. Without further compensation
to me, all negative/slides and prints shall constitute your property, soley and
completely.
I hereby release, discharge and agree to save harmless the photographer, his
representatives, assigns, employees or any persons, corporations, acting under
his permission or authority, or any persons, corporations, for whom he might be
acting, including any firm publishing and/or distributing the finished product,
in whole or in part, from and against any liability as a result of any
distortion, or alteration, optical illusion, or use in composite form, either
intentionally or otherwise, that may occur or be produced in the taking,
processing or reproduction of the finished product, its publication or
distribution of the same.
I hereby warrant that I am (UNDER/OVER) twenty-one years of age, and competent
to contract in my own name insofar as the above is concerned.
I am to be compensated as follows: _____________________________________
I have read the foregoing release, authorization and aggrement, before
affixing my signature below, and warrant that I certify that I am in full
legal capacity to execute the authorization and release and fully understand
the contents thereof.
dated____________________
printed name________________________
signature___________________________
address_____________________________
witness_____________________________
I hereby certify that I am the parent and/or guardian
of______________________, a person under the age of twenty-one years, and in
consideration of value received, the receipt of which is acknowledged, I
hereby consent that any photographs which have been or are about to be taken,
may be used for the purposes set forth in the original release herein above,
signed by the model, with the same force and effect as if executed by me.
parent or guardian____________________________
address_______________________________________
From: [email protected] (Erwin A. Siegel)
================================================================================
Note 16.02 -< Pinout Layout for Kodak Projector's remote control >-------------------------------------------------------------------------------I seem to recall that from time to time somebody asks for the pinout layout of
Kodak Carousel and Ektagraphic, etc. projectors. I happened to be looking in
some old files and noticed I had a copy of a couple of pamphlets by Kodak that
give this information. The Forward/Reverse functions are quite easy to deal with
file:///C|/faq.html (26 of 555) [7/19/2002 3:46:23 AM]
since they consist of nothing more than a momentary switch closure. The focus
control is apparently a bit trickier since it involves the use of at least one
diode. It can also be done with two diodes and this is what I will describe
below since it is easier to do in ASCII.
___________
.___________________________.
|
|
|
|
|
|
|
.---|<---*
|
|
|
|
|
| forward
|
|
v
|
|
O
O
.---*==||=====
|
v
|
|| ^
|
=====-----------O-----------*
|| |
|
^
|
||
---|--|
O
O
|
||
|
|
|
|
|| .--------.
| reverse |
|
|
|| v
|
|_________|
|
---*==||=====
|
|
^
|
|________________|________|
focus
This looks like a DPDT
switch with Center OFF
This was described in two pamphlets that may or may no longer be available from
Kodak's 800 number. They are Pamphlet Number S-80-4, Kodak AV Equipment Memo
and 70-7, Kodak Slide Projector Wiring and Operation. If these are no longer
available from Kodak you can drop in at my office in bldg. 7B-2244 and ask for
a copy.
andy
================================================================================
Note 16.03
-< PINHOLE Photography Book List ^-------------------------------------------------------------------------------I would recommend the following books and article on Pinhole Photography:
"The Visionary Pinhole" by Lauren SMITH, Salt Lake City, 1985, Gibbs
M. Smith, Inc., Peregrine Smith Books.
A history of pinhole cameras, beautiful black and white
photographs, with examples of various types of cameras.
It cost $14.95 when I bought it a few years at the
San Diego Museum of Photography
"The Hole Thing: A Manual of Pinhole Fotografy(sic) by Jim SHULL,
Morgan & Morgan, Inc, Publishers, Dobbs Ferry, New York
"The" how-to-do-it-yourself book. Paperback full of useful
illustrated information, with some black and white photographs.
Probably "the" book.
"The International Pinhle Photography Exhibition"
Published by the Center for Contemporary Arts of Santa
file:///C|/faq.html (27 of 555) [7/19/2002 3:46:23 AM]
Fe, a book full black and white and color photographs
from 22 photographers.
"Pinhole Journal"
Used to be published three times a year, by the
Pinhole Resource, San Lorenzo NM te. 505 536 9942.
A journal devoted to the theory and practice of
pinhole photography--I don't know if it is still
published.
Popular Photography, January 1988, Volume 95, No. 1 had
an extensive article on the subject with good practical tips
on how to get started, how to make the pinholes, etc.
The small "KodaK camera with 126mm film was actually made (I think)
by Time-Filed Co, Newark, Delaware 19711 and called the PinZip 126
and used Kodak Instamatic Cartridge, Kodacolor II, Kodachrome 64,
and Verichrome Pan. It cost $11.95 in 1987 and was available then
through the Pinhole Resource. Again, I don't know the current status
of the camera, or Pinhole Resource. If it is still around, that is
probably the best source of information on the subject.
++++++++++++++++++++++++
[email protected]
RFE/RL Inc
Munich,Germany
================================================================================
Note 16.04
-< Reciprocity Failure - Folk and Real Description -------------------------------------------------------------------------------From: [email protected]
Organization: Rochester Institute of Technology
In article <[email protected], [email protected] (William Tyler) wri
tes:
>In article <[email protected] [email protected] (Yumee
A. Shim) writes:
>>a question for all you photo pros out there... could anyone please explain to
>>me what reciprocity failure is exactly, and how it affects exposure times?
....
The reciprocity law states something to the effect that for a given light level
you achieve the same exposure by using a short exposure time and a large
aperture or a long exposure time and a correspondingly small aperture. While
this law does not fail, the photographic emulsions do in terms of giving the
same density for the same exposure if the exposure time varies widely.
An analogy I sometimes use, rightly or wrongly, is that film is sort of like a
bucket that becomes filled as you pour water into it. Proper exposure is
accomplished under any condition that fills the bucket to the brim. Not enough
is underexposure and too much overflows and is overexposure.
If you have a second bucket of the same volume as the first and you pour its
file:///C|/faq.html (28 of 555) [7/19/2002 3:46:23 AM]
contents into the first one you would assume that you could fill the first
bucket exactly to the brim (and achieve proper "exposure") automatically since
they are of the same volume. The problem is that you can transfer the contents
pouring a small stream over a long period of time or dumping the contents from
one to the other quickly.
Unfortunately the situation is complicated by the fact thatthat the first
bucket happens to have a very small hole in it and if you take too long to
transfer the contents by the time you are done you will find that you have not
quite filled the first bucket but must add an additional amount of water to
reach the brim. This situation gets worse as the time increases.
At the other end, if you try to transfer the water quickly you are bound to
splash a considerable amount and this will again fail to bring the level to the
desired condition. You need to add an additional amount of water (or exposure
or light) again.
Obviously, over a certain range of transfer times one can quite accurately
transfer the contents of one bucket to the other with no major problem. I guess
it would depend somewhat on the size of the leak and the design of the bucket.
There must be an analogy to film I suppose.
There is an additional factor associated with reciprocity law failure of
emulsions (and just about anything else) and that is the effect on contrast.
This means that areas exposed to different light levels for the same time
produce different photographic effects (or density) than you would expect if
the reciprocity law held true. For this reason there is a development
compensation that is usually made to bring the contrast of the negative to some
predetermined level.
Getting back to the bucket analogy I suppose that to visualize this effect you
would have a series of different volume buckets to fill in the same time and
finally you would be looking at the percent-full value in each bucket to
determine overall contrast.
Anyway, this is only partially worked out and comments, additions, criticisms,
etc. would be appreciated.
Andy
............................................................................
..
and now a more scientific explanantion....
From: [email protected] (Francis Vaughan)
Organization: Adelaide Univerity, Computer Science
In article <[email protected], [email protected] (Yumee
A. Shim) writes:
|
|
|
|
|
a question for all you photo pros out there... could anyone please
explain to me what reciprocity failure is exactly, and how it affects
exposure times? i've just started working with pinhole cameras, and
long night exposures, and am wondering how and when it would affect my
pictures.
file:///C|/faq.html (29 of 555) [7/19/2002 3:46:23 AM]
To understand reciprocity failure we need to first understand
reciprocity.
When using conventional films under ordinary circumstances we treat the
film as an integrator of light, that is given a dose of x photons it
will deliver y density, where the transfer function is fairly well
understood for that film. This integrating model allows us to trade
off arrival rate of photons against time. In ordinary terms, arrival
rate is controlled by the f stop, and the time by the shutter speed.
Trading these off gets us the law of reciprocity, where
Relative exposure = Time/f number.
Reciprocity failure is simply the breaking down of this relationship
because the film ceases to behave as a light integrator.
The following is paraprased from "Colours of the Stars" David Malin and
Paul Murdin, Cambridge University Press, 1984 ISBN 0 521 25714 X. A
book I cannot recommend too highly.
The photographic effect on an emulsion does not just depend upon the
number of photons received, but also upon their rate of arrival. This
effect is however not usually seen until exposures get quite long.
When a photon is absorbed by a silver halide grain a photo electron and
a positively charged hole are produced. Both the electron and the hole
are mobile until they either recombine or one or both are trapped. A
trapped electron will neutralise a silver ion, forming a single
unstable silver atom. This atom may be lost (ionised) by recombination
with a hole, or by the action of impurities. If another photon
releases a second electron which goes on to form a second silver atom,
the two atoms can combine to form a stable pair. This pair can then
be added to by additional single silver atoms. Eventually enough
silver atoms aggregate together so that the grain will contain a
developable latent image.
Clearly there is a threshold of photon arrival beneath which a latent
image is never produced no matter how many photons are actually
delivered. Above this threshold many photons will never add to the
growing latent image. Up to a point, the faster photons arrive the more
sensitive the film is to their arrival. Film speed is not constant and
the reciprocity law fails.
The effective drop in film speed can be very large, ten times for exposures
of the order of a minute, twice for exposures around a second.
The above description covers the failure of the reciprocity law for
long exposures, there is a similar failure, with a different mechanism,
for very fast exposures. Again, the effective film speed drops.
Most manufacturers provide some general rules for exposure compensation
for very long or very short exposures. These rules are usually
accompanied by a caveat that they are only a guide, and you are well
file:///C|/faq.html (30 of 555) [7/19/2002 3:46:23 AM]
advised to bracket all exposures and test individual circumstances.
Colour film is more fraught. The individual layers in the film often
suffer from different levels of failure resulting in significant colour
casts. Careful use of filters can help, although the filters
themselves lengthen exposure further complicating matters.
Astrophotograhy has used a number of techniques to combat reciprocity
failure. Cooling the film (dry ice has been a favorite) reduces the
mobility of electrons and holes, slowing the recombination. Removal
of contaminants has produced very good results, the principal
contaminants being water and oxygen. Baking the film in dry nitrogen
eliminates the contaminents for long enough to make an exposure.
Seeding the crystals with single silver atoms also raises the photon
conversion rate. Adding some hydrogen to the gas baking mix causes the
production of single silver atoms. Eventually this process is limited
by chemical fogging of the film.
Francis Vaughan
================================================================================
Note 16.05
-< Toners - home made stuff -------------------------------------------------------------------------------TONERS
this week's stuff is about toning. 90 % of the procedures
used in the 1910-20 era used AuCl2, or Platinum salts. Both Gold and
Platinum compounds are expensive, so I'll describe methods concerning
cheaper stuff. Anyway, if you want, I can e-mail recipes to use the
expensive material.
First, bleach COMPLETLY the photograph in
-water.........100 cm3
-Potassium ferricianide.......2 g.
then, depending in the tone you are interested in, go to
for red :- water........100cm3
- Uranium Nitrate...8 g.
-HCl......1 cm3 (18 M).
for blue :- water..........100cm3.
- FeCl3...........5 g.
- HCl............1cm3
for green :- water............100cm3.
- Fe Citrate........5 g.
stop the bath when the image is a little overtoned, then wash in a pretty
acid water (with HCl), then fresh water. Go to a traditional fixer for
5 minutes and give a final wash with water.
More specific formulas, feel welcomed to ask me.
file:///C|/faq.html (31 of 555) [7/19/2002 3:46:23 AM]
From: Guillermo Brajovic Allende
Lab. Ecologia Pelagica
Depto. Oceanologia
Universidad de Concepcion
Concepcion, CHILE.
[email protected]
"I smoke and I eat red meat
because I want to live, not
to last" G.B.A.
================================================================================
Note 16.06 -< Thermography = Infrared Photography of Hot Objects -------------------------------------------------------------------------------INFRARED PHOTOGRAPHY OF HEAT LOSS better known as THERMOGRAPHY
>Re: John's inquiry about film available which could be used to photograph a
>building, and the resulting image could possibly indicate areas of heat loss.
John, unfortunately this can not be done with film. While heat-loss is certainly
an infrared effect the temperatures are much cooler than those to which
photographic materials can be sensitized. The most sensitive IR films only
respond to temperatures just below visual red hot. Something like an iron set
to its highest setting.
An indicator of the trouble one would have if, in fact, you could sensitize
film to ambient temperatures is the fact that your own body is hotter than most
buildings. This means that you would be exposing the film by the mere action of
handling the casette while loading the camera.
The kind of instrument that is used to display "thermal infrared", that is
temperatures in the vicinity of body heat, was widely used in the Gulf War.
There they detected in pitch dark conditions the location of tanks whose
engines still retained some heat or soldiers or any activity on the ground that
generated heat beyond that normally present on the desert floor.
These "thermographic" cameras typically compare the temperature of an image
point against a reference temperature provided by liquid nitrogen. One way to
do this is to place a thermocouple at the image and another in the nitrogen.
The slight temperature differential produces a current which can be measured
and displayed on a TV screen as a particular brightness level.
If you have a thremocouple that responds quickly you then move the image of a
scene over the thermocouple using rotating mirrors. You "scan" the image in
fact by having one mirror move the image from side to side and the other move
the image downwards. They are synchronized so that the sideways mirror spins
maybe 50 times faster than the downwards mirror. This gives you 50 vertical
lines of resolution for each picture. Horizontal resolution will depend on how
fast the thermocouple can respond to temperature changes.
The scanning action of the mirrors is also synchronized to the electron gun
deflectors and the electron beam scans the CRT screen from side to side and
downwards at the same timeas the mirrors move the image past the temperature
sensing thermocouple. A thermal picture is thus displayed on the screen. These
days this can be done at 30 pps and pseudo color can be added by electronic
manipulation of the grey levels. In fact, colors can be assigned to grey levels
such that small ranges in temperature are keyed a particular color on the
screen making quantitative analysis of a scene quite easy.
file:///C|/faq.html (32 of 555) [7/19/2002 3:46:23 AM]
You point a camera like this at a building and hot areas can be made to look
red while cool areas are made blue and heat loss is easily detected. If you
lean up against a wall and then leave these cameras can detect the fact that
someone leaned up against the wall for a considerable time after the thermal
imprint was made. They are useful most anywhere that temperatures need to be
mesured and displayed in a non-contact fashion and over a large area
simultaneously.
Unfortunately the least expensive camera that can do this costs about $ 20,000.
One US manufacturer is Inframetrics. Hughes and Eastman Kodak are others.
Barnes Engineering in England and AG "something" in Sweden (I think) are others.
It is interesting to note that the lenses in these cameras are opaque to the
light that we see. They look like polished black glass. Some of the newer
cameras do not require liquid nitrogen and produce their own reference
temperature somehow. There may be some cameras around that do not use rotating
mirrors but rotating mirrors were the basis on which the industry developed.
Well, I hope this is a start anyway. I may have oversimplified some things but
believe this roughly describes the process of imaging by thermal infrared.
Andy
================================================================================
Note 16.07
-< Reverse Text Slides on Vericolor Slide Film -------------------------------------------------------------------------------From: [email protected] (RON SPEIRS)
Subject: Re: White on Blue from Black on White
Organization: Evans & Sutherland Computer Corp.
I need to make some white on blue slides from black on white originals.
How do I go about doing this using Kodak 5072 film?
The following is taken from Kodak Publication E-24,
"KODAK VERICOLOR Slide and Print Films":
------------------------------------------------------------------------------"Making Reverse-Text Slides
You can use KODAK VERICOLOR Slide Film to produce reverse-text slides with
white or near white letters on a dark or colored background. To make a
reverse-text slide, photograph dark letters on a white background with color
compensating filters over the lens. For backgrounds of various colors, use
the filters and exposures given in the tables below.
Use a 3200 K light source. To determine the shutter speed and lens aperture
for exposure, use an incident light meter set at the exposure index indicated
below. When you add the filters in front of the camera lens, increase the
exposure as shown in the tables. Make an exposure series of at least +-1
stop in 1/2 stop increments. Keep the exposure time between 1 and 8 seconds.
Note: Reverse-text slides exposed with KODAK WRATTEN Gelatin filters usually
have more saturated colors than slides made with KODAK Color Compensating
Filters.
file:///C|/faq.html (33 of 555) [7/19/2002 3:46:23 AM]
Using Color Compensating Filters
Use an exposure index of 2 with a filter pack of CP60R + CP50Y over the light
source. Place the color compensating filters over the lens.
Background
Color
in Slide
KODAK Color
Compensating
Filter
Increase
Aperture by
(f-stops)*
Magenta
Blue
Cyan
Dark Green
Yellow-Orange
Dark red
75G
1
50R + 50Y
1.5
70R + 05Y
0
50M
1
90B + 40C
2
Remove the CP filter
0
pack from the light
source. Add 90C +
20G in front of the lens.
Using KODAK WRATTEN Gelatin Filters
Use an exposure index of 8 with no filters over the light source.
KODAK WRATTEN Gelatin Filter over the lens.
Background
Color
in Slide
KODAK WRATTEN
Gelatine Filter No.
Increase
Aperture by
(f-stops)*
Red-brown
Purple
Dark blue
Cyan
Dark green
Red
Orange
Dark yellow
Magenta
None
12 (deep yellow)
12 + 106 (amber)
29 (deep red tricolor)
34A (violet)
38A (blue)
44 (light blue-green)
47 (blue tricolor)
61(deep green tricolor)
0
2
2
4
4
4
4
4
5
Place the
*You can increase exposure by extending the exposure time, as long as it does
not exceed 8 seconds.
----------------------------------------------------------------------------When I use this film in this manner, I use the settings for Compensating
filters from the first table, and dial them into my color head which I
use as the light source. Ron
..............................................................................
and some more thoughts ...
Vericolor Slide film is a negative working color material without the orange
mask. Since it is negative it will reproduce any color as its complement.
Therefore to produce white letters in your finished slides you make your
original art have black ones. To make the background blue you could either
prepare your original art on yellow stock or on white stock but then expose
file:///C|/faq.html (34 of 555) [7/19/2002 3:46:23 AM]
through a yellow filter.
Often, instead of photographing reflection copy, photographers will make a
Kodalith positive slide and then copy that with Vericolor Slide film since this
will tend to make the resulting slides have more contrast.
Another approach is to use regular reversal film and after having made lith
copies (negatives) of your lettering (which is now clear white letters on a jet
black background) you copy them with the reversal film. You then make a second
exposure to a "white" or clear slide through a blue filter to add the
background color that you want..
Another option is to "flash" the whole roll to blue light after having
exposed all the line copy. This will result in no frame lines showing in your
finished film however.
andy, [email protected]
================================================================================
Note 16.08
-< Flange to Film Distances for Photo Hackers -------------------------------------------------------------------------------FLANGE TO FILM DISTANCES and ADAPTERS
Re: adapting SLR lenses to Leica or to each other is possible by coupling
preferably metal body caps to metal rear lens caps. I would steer clear of
plastic caps as the chance of dropping the lens is substantially greater.
It helps to know what the flange to film distances are in order to make the
adapter the right thickness. I saved a list of lens flange to film distances
for various camera bodies (pre AF) and have listed some below in case you might
find this info useful.
Leica (screw)
Canon (screw)
Nikon
Pentax K
Alpa Bayonet
Contax RTS
Konica Autoreflex
Olympus OM
Petri Bayonet
Rollei 35
Voigtlander
28.8
28.8
46.5
45.5
37.8
45.5
40.5
46.0
45.5
44.7
44.7
mm
mm
mm
mm
mm
mm
mm
mm
mm
mm
mm
Leica (M bayonet)
Canon (FD and earlier)
Minolta
Exacta
Contarex
Ikarex BM
Miranda
Praktica/Pentax *
Ricoh Bayonet
Topcon DM
Yashika FR, FX
27.8
42.0
43.5
44.7
46.0
44.7
31.5
45.5
45.5
44.7
45.5
mm
mm
mm
mm
mm
mm
mm (41.5 mm?)
mm
mm
mm
mm
* also Alpa 2000 Si, Argus, Chinon, Contax D and S, Cosina, Edixa, Fujica, GAF,
Ikarex TM, Mamiya?sekor, Petri, Pentacon, Ricoh, Spiraflex, Vivitar, and
Yashica SLRs with M42 Universal mount. (Maybe these should be 45.46 mm?)
Steve Morton
([email protected]) added the following
Leicaflex
Jenaflex
Canon EOS/EF
47.0 mm
44.4 mm
44.0 mm
Now here is another listing from Hiroshi "Gitchang" Okuno in Japan whose page
file:///C|/faq.html (35 of 555) [7/19/2002 3:46:23 AM]
links to this data (note that in some cases there is a slight discrepancy):
OLYMPUS-Pen F
Alpa
Konica AR
MIRANDA
Canon R/FL/FD
Minolta MD
PETRI
Canon EF
MINOLTA &A
Rolleiflex SL35 (Q.B.M)
EXAKTA
PENTAX K
M42
CONTAX (YASHICA/KYOCERA)
Nikon F
Contarex
OLYMPUS OM
LEICA R
Mamiya 645
PENTAX 645
EXACTA 66 (Pentacon-6)
Hasselblad
Pentax 67
Mamiya RZ67
Rolleiflex SL66
Mamiya RB67
28.95mm
37.80mm
40.70mm
41.50mm
42.00mm
43.50mm
43.50mm
44.00mm
44.50mm
44.60mm Q = Quick
44.70mm
45.46mm
45.46mm
45.50mm
46.50mm
46.00mm
46.00mm
47.00mm
63.30mm
70.87mm
74.10mm
74.90mm
84.95mm 74.10mm
105.00mm
102.80mm
112.00mm
Happy hacking and glueing and shooting! I made adapters to fit Canon to Leica
(although Canon makes one of these) and Nikon to Canon and Minolta to Canon
and they're great. I've also adapted Fuji and Miranda lenses to Canon.
andy
================================================================================
Note 16.09
-< EV or Exposure Values Explained -------------------------------------------------------------------------------EV or EXPOSURE VALUES
Can you tell me, what the EV means and how to calculate it? Thanks
EV is a shorthand for a range of shutterspeed/aperture combinations.
EV=0 is 1 sec. at f/1. (If I'm off on this starting point, sorry!)
so 1 sec at f/2 is EV=2, but so is 1/2 sec at f/1.4, but so is
1/4 sec at f/1.
This may seem confusing, but it is convenient for some combinations
of light meters & cameras. Once the meter tells you an EV, then
the camera allows you to set a wide range of shutter speed/aperture
combinations using the EV number as a reference.
This was more common in the 1950's (40's? 60's too?) when cameras
were equipped with an EV scale that coupled the shutter speed lever
with the aperture. You may still find the feature on equipment oriented
file:///C|/faq.html (36 of 555) [7/19/2002 3:46:23 AM]
to professional use. In recent years, some people/organizations have
keyed a specific EV to a specific combination of film ISO/lighting
intensity. EV then provides a reference to lighting intensity. But the
historic use of EV was just a shorthand notation for a range of
equivalent shutter/aperture combinations.
From: [email protected] (Tyrus Monson)
Subject: Re: Exprosure Values ?
Organization: Oregon State University, Corvallis
================================================================================
Note 16.10
-< How to process with Rodinal -------------------------------------------------------------------------------RODINAL
Dilutions and uses of Rodinol
>Hi phorum pholks! Do any of you use Rodinol? I have just bought by
>first jar of it and used it once at 1:50 to develop some T-Max 120. I
>am now shooting Agfa 50asa 120.
I use Rodinal on a regular basis but have found that my negatives tend to be of
lower contrast than I like them when I have followed Agfa's recommendations.
These are some times that were developed and used in the Industrial Photography
area many years ago. Your own individual conditions may dictate modifications to
these suggested times and dilutions and effective speeds. Development is at 68
degrees with agitation every minute.
TRI-X
Light
Intensity
Subject
Contrast
ISO
Bright
Bright
Bright
Dim
Dim
Very Dim
Very Dim
Very Dim
Very Dim
High
Moderate
Low
High
Moderate
High
Low
High
Low
250
400
400
600
800
1200
1600
3200
6400
Available Light
Moderate
Bright
Bright
Bright
Bright
Dim
Dim
Dim
Very Dim
Very Dim
Highest
High
Moderate
Low
High
Moderate
Low
High
Low
Dilution
Time
1:85
1:75
1:50
1:75
1:50
1:65
1:50
1:65
1:50
14
14.5
14.5
15.5
16.5
17.5
18.5
20
22.5
800
1:100
17.5 min
80
125
160
400
400
400
600
800
800
1:100
1:100
1:75
1:50
1:75
1:50
1:50
1:75
1:50
10.5
11.5
11.5
12
12.5
13.5
14.5
15.5
16.5
min
min
min
min
min
min
min
min
min
PLUS-X
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min
min
min
min
min
min
min
min
min
Normal
Moderate
200
1:85
12
min
Panatomic-X (no longer available)(so this should tell you a bit about the time
that these tables were compiled!)
ISO 32
Dilution:
1:100
High Contrast:
18 min
Normal Contrast: 16 min
Low Contrast:
14 min
Date: 30 Apr 1992 15:57:12 -0400
From: ANDPPH@ritvax
Subject: RE: Dilutions and uses of Rodinol
______________________________________________________________________
and here is another suggestion on how to deal with Rodinal...
Subj:
Dilutions and Uses of Rodinal
Re: Note 16.10.
I, too, used to find a lack of contrast with Rodinal but I cured it
by doing the following:
7 ml Rodinal
495 ml water
1.3 grams hydroquinone (one level capful from plastic 35mm
film can.)
Hydroquinone, the zippy ingredient in common M-Q developers, will
boost your contrast. It's pretty cheap and can be had in one pound
quantities. Ask your friendly photo store to get it for you---they
probably don't stock it.
Do one roll in a two reel tank. For two rolls, double quantities and
use a four reel tank. Agitate 1st minute then 10 sec/min.
I go 15 mins. at 70 degrees F for Tri-X. Don't know about T-Max
time/temp. If your shadow detail is ok but highlight areas of the
film needs more density you could just use what you've been using
and add the hydroquinone.
This time is for Texas tap water and my cold light enlarger with
"normal" contrast paper. May or may not be appropriate for someone
else but the hydroquinone principle will still be valid.
Hope this helps.
Joe Walsh
Department of Photography
Amarillo (TX) College
<[email protected]>
================================================================================
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Note 16.11
-< Processing B&W Film in various developers -------------------------------------------------------------------------------DEVELOPING BLACK AND WHITE FILMS
Sender: koller@bolzano (Michael Koller)
Organization: ETH Zuerich
I enjoy developping and enlarging my films myself, and so decided to look for
the developping times in different developpers. Here my results: All at 20C.
Shaking every minute for 10 Sec.
Film
Perceptol 1:1
(Ilford)
ID 11
(D 76)
T-MAX 1:4
Agfa APX 25
Agfa APX 100
Agfa AP 400
12 (25ASA)
11 (50ASA)
14 (200ASA)
7
7,5
--
5,5
6
8
Ilford FP4 +
Ilford HP5 +
Ilfor Delta
14 (64ASA)
15 (200ASA)
10,5(200ASA)
8
7
6(400ASA)
4,5(250ASA)
7
5,5(400ASA)
Kodak TMX
Kodak TMY
Kodak TMZ
-14(250ASA)
15(1000ASA)
9,5
8,5
--
8
7
--
Fuji Neopan 400
Fuji Neopan 1600
-8,5(800ASA)
7,5
7,5
6,5
4,5
For Pushing Neopan 1600 resp. TMZ see the Information for the fims which you
get buying them. Two Films which give very good results in Perceptol(conz.) are
Kodak TMX
Fuji Neopan 400
Percept.: 10 Min.
Percept.: 11 Min.
The time for this two films in 1:1 is too long .
================================================================================
Note 16.12
-< Making Polycontrast Filters with CC filtration -------------------------------------------------------------------------------CC EQUIVALENTS OF POLYCONTRAST FILTERS
The following are the Ilford filter values for Multigrade.
Grade
Kodak
Durst
Y
M
Y
M
------- --0
150
25
92
16
.5
110
33
74
22
1
85
42
56
28
1.5
70
55
46
37
2
55
70
36
46
2.5
42
80
28
53
3
30
90
26
60
3.5
18
112
12
75
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4
4.4
5
6
135
4
90
0
195
0 135
Not available on these heads.
There are settings for single filters but the advantage of the above is that
the exposure time stays constant i.e exposure for 0-3.5 is rhe same
4-5 is double.
So you should make your initial testsat,say grade 3 and set the filters
accordingly. Then if you need to come down you can use the same exposure time
if you need to go up just double it
Further to the recent correspondence on this subject I have come
across the following figures from a suppliers literature:Durst Values
-----------G1 66Y 15M
G2 39Y 33M
G3 20Y 60M
G4 10Y 100M
G5
0Y 178M
* William O`Brien
* E-MAIL [email protected]
================================================================================
Note 16.13
-< How to use Direct Positive Film -------------------------------------------------------------------------------DIRECT POSITIVE FILM
The Kodak Catalog Number for the Direct Positive Developing Outfit
for Tech Pan and T-Max films is Cat No 812 1188
From:
Subj:
IN%"[email protected]" 8-SEP-1992 12:48:17.25
RE: Reversal Processing of T-Max film
>If you have a favorite recipe and instructions on how to process T-Max films to
>achieve superior B&W transparencies I would very much appreciate it if you
>could share this with me and the network assuming that this subject has not
>been worked to death in the last few months that I've been away from here.
There are several B&W films which can be processed to yield positives
Besides the now discontinued Panatomic-X, two other thin-film emulsion films
should work as well: Ilford Pan F and Agfapan 25.
Kodak Technical Pan and T-Max 100 will also work with the appropriate
developer. Following are recipes for 4 developers and other solutions.
The first two, Kodak D-67 and Z-7 were for use with the old Panatomic-X
film, and should be used for the Ilford Pan F and Agfapan. The next two are
formulated to provide good results with Tech Pan and T-Max respectively.
As far as the other solutions go, I cannot explain the differences in
the formulas. Since the bleach and second developer reactions go to
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completion, I really don't think that the different formulas would make
much difference. I would discourage the use of Sulfuric Acid in the bleach
because it is hazardous and hard for a private person to obtain. The
Sodium Bisulfate works just as well. Also, I wouldn't bother with the
FD-70a fogging redeveloper; it only lasts an hour once mixed and light
reversal is easy enough and much cheaper.
FIRST DEVELOPER
Kodak D67
Metol (Elon)
2.0 g
Phenidone
Sodium Sulfite
90 g
Hydroquinone
8 g
Sodium Carbonate Mono
52 g
Potassium Bromide
5 g
Benzotriazole
Sodium Thiosulfate Penta
Sodium Thiocyanate 51% 3.0 mL
Potassium Iodide 0.1%
Water to make
1 L
Time
8 min
Temperature F
68
Z-7
0.25
34
5.6
36
1.6
0.25
T-Max
4.0 g
2.0 g
25
5.0
30
2.0
.03
g
g
g
g
g
100
5.0
60
4.0
3.0
10
1
10
75
mL
mL
L
min
g
g
g
g
g
g
Tech Pan
g
g
g
g
16 g
4.0 mL
1 L
6 min
68
1 L
10 min
68
BLEACH
Potassium Dichromate
Sodium Bisulfate
Sulfuric Acid
Water to make
9.5 g
12 mL
1 L
11 g
22.9 g
9.5 g
66 g
1 L
1 L
34 g
1 L
90 g
1 L
9.5 g
12 mL
1 L
CLEAR BATH
Sodium Sulfite
Water to make
90 g
1 L
50 g
1 L
SECOND DEVELOPER
FD-70a
FIXER
F-5 or
F-6
Same as
First Dev
without
Thiocyanate
Dektol 1:2
F-5
Usual film
Fixer
Usual
Film Fixer
D-19
Processing Schedule
First Developer
Rinse
Bleach
Rinse
Clear Bath
Rinse
Re-exposure
See times under formulas
2 minutes
2-3 minutes
1 minute
1.5-2 minutes
1-2 minutes
30-60 seconds each side
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Second Developer
Rinse
Fixer
Wash
Photo-flo Wash
Dry
3-4 minutes
30-60 seconds
Normal time for fixer used
Appropriate time for fixer used, 10-20 minutes
___________________________________________________________________
Agitation in the solutions should be 5 seconds of every 30 seconds.
After the bleach step, re-exposure to light renders the remaining silver
developable. The use of stainless steel or clear plastic processing reels
makes it possible to re-expose the film while on the reel. Optimum re-exposure
is about 800 foot-candle seconds, but the amount of re-exposure is not
critical. Both sides of the reel should be exposed for 30-60 seconds to a 60
or 75 watt bulb at 12 to 18 inches. The reel should be rotated constantly
during re-exposure. A 30 to 40 second exposure to a 40 watt fluorescent tube
at 2 to 4 inches can also be used. No variation in density will be apparent
until these exposure values are changed to about 1/10 or 10 times the
given amounts.
As can be seen from the formulas, the steps following the first developer
are not too critical; although the clear bath should not exceed 2 minutes.
Also, room light is OK after the bleach step. Typically you would expose
Ilford Pan F or Agfapan 25 at about twice their ISO speeds. My source for
T-Max 100 indicates that it can be used at its negative rated speed of ISO 100.
The Tech Pan should be rated at ISO 40. My sources also indicate that
D-67 can be made by adding 3 mL of Sodium Thiocyanate 51% to D-19 developer.
If anyone decides to try these formulas, be sure to shoot a test roll first
and bracket to find optimum exposure. Since you will get a positive, follow
the exposure rules as for color slide film: More exposure = lighter, less
dense image; less exposure = darker, denser image.
Note 17.01
-< Infrared - basic information >-------------------------------------------------------------------------------INFRARED
From: [email protected] "andrew davidhazy"
There are several filters to choose from. 87 is but one of a series. Others are
88A, 87C, 89B, and 70 are others. They differ in the cut-off wavelength. The
Kodak High Speed Infrared film is itself only sensitive to about 900 nm. ISO
ratings are not necessarily useful becasue the subject one may be photographing
may have a different ratio of IR to visible reflectance than a "normal"
subject.
>This filter allows only infrared light thru. However, you cannot see through
>this filter, so you must check all your readings, etc, then place the filter
>over the lens and snap the picture.
In the case of a static subject this is of course not a problem. With a
rangefinder or TLR camera it is not a problem either since you are not looking
through a lens. On the other hand, with an SLR you could cut a piece of IR
filter down to the size of your film aperture gate (about 24 x 36 mm) and then
install this just in front of the film plane or just in fron of the shutter
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frame, behind the mirror of the SLR. With some SLR's that have hanging metering
devices behind the main mirror this needs to be done VERY carefully. It is
better to just place it directly in front of the film.
>A flash is probably not going to do you much good in this case, time exposures
>would probably do better.
I think a flash could be very useful especially if AC power is not readily
available at the location that IR photography will take place in, such as in
caves, dungeons, etc. :-)
>Be sure you have the owners manual for the camera lens as well, since the
>focusing for infrared film is different. This is usually explained in the
>owners manual.
yep
>P.S. Konica has a very nice infrared film that I've had quite good luck
>with.
While it is infrared it's sensitivity extends only out to 750 nm or so. I would
like to suggest that at the inexpensive end simple IR image converters such as
used for some surveilance work and for darkroom inspection in photo labs or
more sophisticated IR imaging video cameras at the more expensive end may also
be suitable for archeological applications.
andy
================================================================================
Note 17.02
-< Stereo Photography Discussion >-------------------------------------------------------------------------------STEREO MATERIAL
There is a company somewhere inthe midwest, I believe, that uses a
computer program to produce large format rear-lit transparencies that are used
for autostereo displays. You might have seen them in various airport lobbies.
They don't used a lenticular grid but rather black-bar barrier strips -- very
easy and cheap to produce -- ideal for large format displays.
David Hutchison, STARLOG Magazine
INTERNET: [email protected]
-----------------------------Enjoyed reading the variuous descriptions, and will definitely
try some of the refinements which have been described.
My method is quite similar to that described by Ken Luker, but I
cut all my pairs and lay them out before mounting any of them.
Instead of relying on the heatseal mount's tabs for alignment,
I use a steel ruler, its top edge pressed firmly against the
mount in alignment with the top edges of the bottom horizontal
tabs, and I then gently push the bottom edge of each film chip
against the edge of the ruler. I use a very small piece of
scotch tape to hold the chips temporarily while checking the
alignment in a hand viewer , then slide the mount-with-chips
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out fo the viewer and onto my ironing surface. If done right, this
virtually guarantees perfect alignment (i.e., the bottom edges
of the chips are along one straight horizontal line). However,
I seem to mess it up about every 10th slide, and can't figure
out why.
Larry Glazer
-----------------------------Date: Wed, 25 Nov 92 9:59:02 WST
From: [email protected] (Jennifer Cross)
Subject: Re: homebrew autostereo
Hi All!
>
> > I also suspect the average laser printer can't print small enough dots
>
> I can think of two possible solutions:
>
Print at whatever resolution the printer will allow and then reduce
> it in a photocopier.
This might help, but you will start getting problems with the photocopier
toner grain size (often pretty corse). The new HPO laserjet 4 claims
600 dpi + dot size control + superfine toner which should make a pretty
clear print but I haven't seen one yet.
>
>
Try using it directly on a screen. (Assuming the screen has the
> right resolution, can always output to a smaller screen if not)
my Sun (mono) monitor is 72 dpi, square pixel... I think the Macintosh
screens feature a similar dot pitch. Most good color monitors
vary in dot pitch between the horiz and vert direction (horz is the
quoted figure and works out to about 70-90 dpi) but this is for a single
color, so the "colored pixel" spacing is considerably more (say 40 dpi)
>
> Unfortnatly, it's been about 8 years since I did any programming and that
> was two computers ago. I wouldn;t have a prayer of trying out any of the
> above ideas.
If the above physical constraints work with the lenticular screens, the
programming to interleave n images is pretty trival if all the images
are the same resolution (and the same file format :-)
Lets have suggestions for resolutions and file formats required and
I'll see what I can do. (subject to work and holiday celebrations of
course :-) (happy turkeyday to all those americans out there!)
Yours...
-___
(
>
/)
(voice) +61 9 362 6680
__/_/> ____ ____ o // _ __
(home) [email protected]
/ / (__/ / <_/ / <_<_//__</_/ (_ @ Beautiful Perth, Western Australia
<_/
/>
(work) [email protected]
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</
(voice) +61 9 380 3968
================================================================================
Note 17.03
-< Compensation for Enlarger Magnification in "C" >-------------------------------------------------------------------------------ENLARGER EXPOSURE CALCULATION, CLARIFICATION AND "C" CODE
This is a re-editted and expanded version of a previous posting. I recieved
mail requesting clarification. The original posting pertained to enlarger
exposure calculation.
I hope this stimulates some interesting discussions.
Included are three sections:
1) The first is a broader brush view of the methodology I use.
2) The second is a copy of the original posting that sparked the
request for clarification.
3) The third is documented 'C' program that I used
to generate the scale on my enlarger.
Even though I am distributing this information without charge I retain
the copyrights to it. Please do not reuse or redistribute it without
permission. (C) 1992 Charles J. Luciano
If I still haven't made this clear enough, maybe we need to talk. Anyway
I am happy to help out in any way I can.
Sincerely,
Chuck Luciano
[email protected]
Part 1:
Let me start by saying that I try to work towards minimum effort in my
darkroom work, and that this begins when buying film, continues behind the
camera, it continues in film developing, and culminates in printing. There
are a number of "tricks of the trade" that I employ to acheive this and I'd
like to address the whole process.
I have a tendency to use one type of film as much as possible. Personally
I prefer Vericolor III type S. I find that when printed on the middle contrast
RA-4 paper (supra) I get very good results. I do use other types of films, but,
since I mainly shoot people anyway, VPS works for me.
I try to buy as much film of the same emulsion number as I can afford. With
VPS I buy bulk and roll my own.
I try as often as possible to use incident light readings for available
light and guide number calculations for flash. The goal here is to make every
negative "perfect", or at least the same as every other.
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To I develop negatives I buy gallon sizes of C-41 chemicals. I mix the whole
gallon of developer, but I mix Bleach, Fix, and Stab in pints. When I store
developer I put a shot of dust off in the bottle which displaces the oxygen
and makes a gallon of chemistry last a long time. I reuse Bleach,
Fix, and Stabilizer about 5 times before tossing, but I __NEVER__ reuse
developer. I work at making sure that the process ___DOES__NOT__CHANGE__ from
one time to the next.
I tend to buy paper in largish quantitys. I recently got a deal on 600 feet
of 11 inch paper in rolls (6). Again all the same emulsion number.
The result of all of this is that if I take a picture in open sunlight,
when I go to print it, the same filter pack I used for another open sunlight
shot 20 rolls ago still applys.
Now I could go into a lot of detail about the methods above, but, I was
asked to clarify how I calculate exposure on my enlarger.
I have a calibrated scale on the column of my enlarger that lists a time
for every height. Initially I accomplished this by using an analyser. If I
move the head of the enlarger I read the new exposure time off of the column.
The aperature always stays the same.
So now I've shot a roll of film and I put it in my contact printer. I put the
head a height that covers all of the negatives and focus (important!). I set
the aperature to f9.5 (this seems to be average for the times I use), and make
a contact sheet. Based on all I did to get the exposure right, I get most of
my shots within 1/2 stop. If there are some shots that are too light or dark
I may make another contact sheet or two a stop under or over. Maybe even
2 stops under or over if I really blew shots I care about.
Now as I'm chosing shots I want to print. I can look at the contact sheet
knowing the aperature that was used for the sheet. Of course I'll judge the
shot on the contact sheet that was closest. I may decide to make a small
compensation from the aperature used to make the sheet.
And here is the rub! Once I arrive on an exposure in the form of an aperature.
I can set the enlarger head to the magnification I want, read the exposure time
off the column for that magnification and BINGO! I get a print that matches
the exposure in the contact sheet. No screwing around. _DONE_ !
Initially I calibrated this whole approach using an analyser and by making
test prints. Later on I acquired mathematical formulas that related the height
of the enlarger head to exposure. I wrote a program that calculated the
exposure time and magnification on 1/6 inch increments and printed it on a
6 line per inch printer and voila! a direct reading scale that I attached
to the column of my enlarger.
There are a couple of boundary conditions that I can also handle using this
method.
I don't like to use my enlarger lens either all the way open or all the
way closed. All the way open can bring out distortions in the lens. All the
way closed can bring out diffraction characteristics in the lens. My lens goes
from f4 to f22. I try to use it between f5.6 and f16.
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The other boundary condition is when exposure times get to be under 3 seconds
or over a minute. Under 3 seconds is a problem because when the enlarger bulb
is turned on is doesn't come on instantly, it starts out red, then yellow then
white. Turning off it does the reverse. As it's cooling the red emissions may
continue for 1/2 second after the blue is gone. I find very short exposures
will throw color balance out of whack. Likewise over a minute reciprocity
failure takes its toll in both exposure time and color balance.
The solution is simple. I consider the exposure time that I read from the
column to be a starting place. In my note taking I refer to this time as "C".
If I have a print that prints well using "C" and f9.5 at magnification 10
where C is 9.53 seconds, that I'd like to print at 27X, where C is 69.32
seconds, I'll cut the time in half and open the lens up a stop, thus avoiding
the need to compensate for reciprocity. When I record the exposure used I
simply record C/2 at f6.7.
Part 2:
I have devised an interesting method of calculating exposures on my
enlarger. I started with a successful print made from an average density
negative using f8 on the enlarger. What I figured is that the exposure is
related to magnification, and the magnification is related to the height of
the enlarger head.
I obtained formulas that take the negative to subject distance and convert
it to a magnification. I then put a negative in the enlarger and measured
the neg to paper distance and the magnification. By using the formula I found
that my 50mm (nominal) enlarger lens is actually 53.something millimeters.
Once I had the exact focal length, I wrote a computer program to print
magnifications, neg to paper distance, and a time value. The time value at the
height where I made the test print matched the time I actually used at that
height. The program printed out the data in 1/6 inch increments. I printed it
out on a printer that prints 6 lines per inch. I now have a direct reading
scale attached to the column of the enlarger.
Now when I print a negative I always set the time to the scale on the column.
Sometimes (like when doing B&W) I can't get the lens opening to match the time,
no problem! When this happens I simply use the time on the column *2, or *4, or
/2, or /4 or whatever. When I make notes on the exposures used to print a
picture I record the time as "c" or "C * 2" or whatever. "C" is the "Column"
time.
So now anytime I print a picture I have a direct reading means of compensating
for changes in magnification. It speeds things up very nicely.
Now why do I bring this up now? Because of the f-stops discussion. When I
record f-stops I do so in 1/4 stop increments. Here are the numbers I use:
2.8
4.0
5.6
8.0
3.0
4.4
6.1
8.7
3.3
4.8
6.7
9.5
3.6
5.2
7.3
10
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11
16
22
12
17
24
13
18
26
14
20
29
Note that all of these numbers do not conform to the same decimal accuracy,
they are simply accurate enough to distinguish them from one another.
No I do not have them memorized! I have a little post-it note on my enlarger
with them written down.
Interestingly enough a I made the acquaintence of a fellow who works for
ESECO, a company in OK that make real high end custom lab type enlargers. He
told me that their enlargers automatically calulate exposure in this way by
sensing the height of the head. Their enlargers are microprocessor based.
All For Now,
Chuck Luciano
[email protected]
Part 3:
/*
Print a time scale for enlarger column. Note that this program works
for enlargers with a head that moves vertically. If your column is
angled, a change is needed.
Don't forget to link with math library.
The mag function takes three arguments. The first is a focal length
the second is a constant multiplier.
These were determined experimentally. I first set the constant multiplier
to 1. I made several measurements of my enlargers actual magnification
at various heights. The two commented out arrays contain the measured
heights and magnifications. I then printed the predicted magnification
and the measured magnification at their ratios at the measured heights
and "Tuned" the focal length until the ratios were constant. Then I
"Tuned" the constant multipliers until the ratios were all around 1.
The reason for the 5.23cm focal length is that the 50mm stamped on the
lens is a nominal dimension. The reason for the constant multiplier is
that the formula used actually ignores the distance between the front
and read nodal points of the lens.
The reference time is the time value I wished to be at the reference
height. In other words I started by making a test print at f9.5 with
the head at ref_ht and the time used was ref_time.
This is why my average negative comes out at "C" seconds at f9.5.
*/
#include <math.h>
#include <stdio.h>
float mag(f,o,d)
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float f;
float o;
float d;
{
float d1p,d1m,mp,mm;
d1m = (d - sqrt(d*d - 4.0 * d * f))/2.0;
mm = (d - d1m)/d1m/o;
/* printf("%f,%f\n",f,d,d1m,mm); */
return mm;
}
/*
float hts[] = {
24.5,40.8,60.6,80.1,105.2,110.0,135.2,160.3,187.8,0.0
};
float meas[] = {
7.90,19.9,33.4,46.7,64.0,67.1,84.4,101.4,119.4
};
*/
main()
{
int i;
float f = 5.23;
/* Focal length in cm */
float o = 0.99;
/* Magnfication multiplier */
float ref_ht = 69.1;
/* Reference height */
float ref_time = 12.0; /* Reference time */
float mag_const = pow(mag(f,o,ref_ht),2.0);
float d,m,e,siz;
/*for (i=0;hts[i] != 0.0;i++)*/
/* Loop where d starts at 200cm down to d <= 24cm.
increment is 4.2333mm (1/6 inch).
If your chassis is on a slanted rail, this is the constant you
need to modify. It must equal the change in elevation when the
head moves 1/6 inch along the rail.
*/
for (d=200.0;d>24.0;d-=(1.0/6.0*2.54))
{
/* d = hts[i];*/
m=mag(f,o,d);
siz = m*3.50;
/* Print this while "TUNING" */
e = pow(m,2.0) / mag_const * ref_time;
printf("%5.2fcm,%5.2fX,%6.2ft\n",
d,m,e );
}
}
From: [email protected]
file:///C|/faq.html (49 of 555) [7/19/2002 3:46:23 AM]
================================================================================
Note 17.04
-< Pinhole Photography Primer >-------------------------------------------------------------------------------SOME ASPECTS OF PINHOLE PHOTOGRAPHY
From:
[email protected] (John Bercovitz)
Organization: Lawrence Berkeley Laboratory, California
>When building a pinhole camera, what is the optimum size for the pinhole?
>I thought I read once that it was about 1/200th of the focal length.
There was an article in the "Pinhole Journal" by a fellow named Connors who did
picture quality tests with various pinhole diameters. Connors found that the
best resolution resulted when the diameter of the pinhole in inches was =
SQRT(.000054 * "focal length" in inches). As I recall, he did his tests with
the subject at fairly ordinary distances. As an example, for a "focal length"
of 6", you have a diameter of SQRT(.000054*6) = .018 inches. If you like your
formulae with bigger constants, you could also say diameter in inches =
.007*SQRT("focal length" in inches).
The bigger the film format, the better the angular image
resolution.
Here's a table for the 3 focal lengths I use on my 4x5 with B&W Polaroid film:
Focal length
in inches
3.375
6.000
10.666
Focal length
in mm
hole diameter
in inches
drill size
.0135
.0180
.0240
#80
#77
#73
86
152
271
f/no
250
333
444
I like the 6 inch focal length best - I leave it on an old shutter on a lens
board. Many others like the shorter focal lengths. As the astronomer said, an
old felt hat is often the best shutter. Don't worry too much about the focal
length; just get the pinhole _approximately_ the correct focal distance from
the film. +/- 25% would't be noticeable, I'm sure.
There are many methods of making pinholes; here's mine: I sandwich a piece of
.001 inch thick brass shim stock between two 1/16 inch thick pieces of sheet
aluminum and drill through with the drill size from the above table using a
high speed drill motor body such as a Dremel tool or a Moto tool or a Sears'
Lil' Crafty or whatever. The aluminum backing pieces (the "bread" of the
sandwich) keep the burrs to a minimum. After the brass is drilled, I take off
the remaining burrs with 600 grit abrasive paper. Then I ink in the inside
diameter of the hole with a black "Magic Marker" type of thing - whatever's
black and sticks to brass and isn't clumpy so as to leave junk in the hole.
Just be sure to inspect your pinhole with a magnifier when it's done to make
sure you have a good round hole - irregularities decrease image sharpness
considerably. Irregularities can be dirt particles inside the hole so I keep
my pinholes in dust-free environs. You blacken the interior of the pinhole to
cut out reflections off the short cylinder which is the hole's inside diameter.
f/no is always just focal length divided by pinhole diameter, the equivalent of
a lens' diameter of aperture. So the f/no of the 6" focal length pinhole is
file:///C|/faq.html (50 of 555) [7/19/2002 3:46:23 AM]
6/.018 = 250.
I really shouldn't be calling this length the "focal length" of the pinhole as
focal length is a property of a lens, not a pinhole. Pinholes are afocal,
that's their charm, but they do have a distance from the film or image plane at
which they give their best resolution. Maybe I should call this "optimum
length" instead of "focal length".
============================================================================
OPTIMUM PINHOLE DIAMTER
From: [email protected] "andrew davidhazy"
Organization:
Rochester Institute of Technology
A couple other formulas related to determining optimum pinhole diameter:
From Applied Photography, by Arnold, Rolls and Stewart:
______
D = V 3.6vL
where v = pinhole to film distance
L = wavelength of light used
all in same units
From Seeing the Light. by Falk, Brill and Stork
_____
D = 2V vL
where units same as above
From Materials and Processes of Photography by Stroebel, Compton, Zakia, Current
___
D = V v / 141
where D = pinhole diameter in inches
v = pinhole to film distance in inches
From Ilford Manual of Photography
___
D = V v / 125
where units same as in M&P book
From Handbook of Photography by Henney and Dudley (1939)
________
D = V .00007v
where v = pinhole to film distance in inches
================================================================================
Note 17.05
-< Processing Infrared Film - How To >-------------------------------------------------------------------------------INFRARED FILM PROCESSING
The information for processing IR film is taken from the Kodak Data Sheet for
its HS Infrared film: This assumes you use a small tank and 135 roll film:
Development time in mins
Developer
65F 68F 70F 72F 75F
-------------------------------file:///C|/faq.html (51 of 555) [7/19/2002 3:46:23 AM]
68F is the recommended temperature
TMAX
D-76
13
HC-110 Dil B 7
D-19*
7
11
6
6
10 9.5
6 5.5
5.5
5
4
8
5
4
*D-19 Gives maximum contrast
Film Speeds - these numbers are guides only - use them as starting points:
Film Speed in ASA rating - assumes development in D-76
Kodak Wratten
Daylight or
Gelatin Filter
Electronic Flash
Tungsten
------------------------------------------------No. 25, 29, 70, 89B
50
125
No. 87, 87A
25
64
No. 87C
10
25
None
80
200
================================================================================
Note 17.06
-< How to use Tech Pan in Medium Format >-------------------------------------------------------------------------------TECH PAN
Being another medium format shooter want to be (and in some occusion,
when the moon is just so and the tide is just so, I even dream about
large format), the only b&w film I use is TP and TMAX100. I use
Rodinal one shot for TP diluted 1:100. At 68 degree, I soak it for
about 7 minutes with 5 sec agitation every minute. What you will get
is ultra fine grain and unbelievable tonal range. Nothing in 35mm
format can touch it. Unfortunately, at ASA25, it's a damn pain in
the ass to use. I use 1:3 diluted MicrodolX for TMAX100, and it suprise
me with acceptable result enlarged to 8x10.
-Anthony
From: [email protected] (Anthony Tse)
Organization: Naval Research Lab, Washington, DC
================================================================================
Note 17.07
-< How to determine intermediate f stops >-------------------------------------------------------------------------------INTERMEDIATE F STOPS
To approximate intermediate f/stops, I use
New f/stop = (old f/stop)[sqrt(2)^(f/stop change)]
For example, if you want to stop down 1/2 stop from f/8, take the sqrt(2)
which equals 1.414 and raise it to the power .5 which is decimal equivalent
of 1/2 stop.
sqrt(2)^.5 = (1.414)^.5
=
next
(8)(1.19) = 9.51
file:///C|/faq.html (52 of 555) [7/19/2002 3:46:24 AM]
1.19
and your new f/stop is appr. 9.5
I guess you need a calculator which has y^x function.
From: [email protected]
================================================================================
Note 17.08
-< Making a home-made light slave trigger for flashes >-------------------------------------------------------------------------------SIMPLE LIGHT SLAVE SCHEMATIC
From: [email protected] "andrew davidhazy"
> I'm looking for a simple schematic for a slave flash control. I can't see
> spending $20 for a Vivitar when I'm just going to use the insides anyway.
I made something like this and it works ok. If there is a commercially made
device that only costs $5 I would suggest thay you buy an already assembled
and tested synchronizer. :-)
Low Ohms
High Ohms
___________________________
_______
/
|
|
|
|
|
/ ___|____
C | _______
|
|Silicon|
/ |
|
|_|
| |____>
|Solar _____/
| Small |
| SCR |
|Cell
| | Auto
|
|
|_______>
|
|
| Trans- |
| C106B | A
|
|-------| former |------|
|
------- +
-------G -------
TO FLASH
Most small silicon solar cells should work. Most small audio transformers with
a resistance of about 8 and 400 ohms should work. The SCR could be something
equivalent but it should be able to handle 200 or preferably 400 volts between
its A and C leads. Since a SCR is used the flash needs to connected to it the
right way, meaning the SCR's output is polarized and it needs to match the input
to the flash. If the flash does not fire with the connections wired one way try
reversing them.
================================================================================
Note 17.09
-< FTP file for material in Rec.Photo >-------------------------------------------------------------------------------Is there an FTP archive for rec.photo?
Yes! moink.nmsu.edu (128.123.4.58) has a number of possibly
useful files. Log in as 'ftp' or 'anonymous', with your FTP
client, please do send your real email address as the password,
and look around.
to use this facility you need to learn how to FTP - file transfer
protocol. With this capability you can transfer files from a
host repository. The one above contains photo information files
as well as picture files.
file:///C|/faq.html (53 of 555) [7/19/2002 3:46:24 AM]
Note 18.01
-< Depth of Field Calculation >-------------------------------------------------------------------------------DEPTH OF FIELD
Depth of field is to some extent an arbitrary matter depending upon
what one deems to be "proper" focus. Given this, you can calculate
depth of field, more-or-less.
Near limit of focus
=
F[squared]S
---------------F[squared] + SAC
Far limit of focus
=
F[squared]S
---------------F[squared] - SAC
Depth of field
= (far limit) - (near limit)
C
A
S
F
=
=
=
=
diameter of "circle of confusion" in meters (e.g., .000033m)
lens aperature or f-stop
distance to subject in meters
lens focal length in meters
The depth-of-field result will be in meters.
================================================================================
Note 18.02
-< How to Dispose of Darkroom Chemicals Safely >-------------------------------------------------------------------------------DISPOSING OF DARKROOM CHEMICALS SAFELY
The following is a chart from the article "Pollution Solution",
"prepared by Peter Kolonia and Peter Krause, with technical information
contributed by Krause". It was in Modern Photograph, but the pages it
was on that I photocopied do not have the date on them.
****************************************************************************
Disposing Of Common Darkroom Chemicals
Chemical
Disposal Method
All film and paper developers
Mix developer with acid stop bath, acid
fixing agent, or vinegar until relatively
neutral pH is reached and gradually pour in
drain with wash water. Use pH indicating
paper to determine level of acidity.*
Stop Bath
Mix with developer or borax until relatively
neutral pH is reached and gradually pour
into drain with wash water.
Acid fixer (with or without
hardener), bleaches, and
bleach fixes. (Some fixers
are alkaline and essentially
Mix with developer or borax until relatively
neutral pH is reached and gradually pour in
drain with wash water; or arrange with a
commercial lab to accept exhausted fixer;
file:///C|/faq.html (54 of 555) [7/19/2002 3:46:24 AM]
neutral.
Check with pH paper).
or purchase a silver recovery unit.
Hypo clearing agent
Pour into drain with wash water.
Sulfur-type toners
(brown, sepia, Polytoner)
Pour into drain with wash water.
Selenium, gold,
iron (blue) toners
Heavy metallic content. Use sulfur-type
toners, if possible. Pour into drain with
wash water.
Wetting agent
Dilute slightly with exhausted stop bath or
fixer and pour into drain with wash water.
Stabilizing bath
Gradually pour into drain with wash water.
Sulfamic acid tray cleaners
Mix with developer or borax until relatively
neutral pH is reached and gradually pour
into drain with wash water.
* Available through Edmund Scientific, 101 E. Gloucester Pike,
Barrington, NJ 08007-1380
================================================================================
Note 18.03
-< Depth of Field in C >-------------------------------------------------------------------------------The following two files (one called DOF.H, the other called DOF.C) will
calculate the depth of field with various f-stops, focal lengths, and
distances to subjects. Built in help. Here's how it works:
1
Extract the first file as DOF.H
2
Extract the second as DOF.C
3
$ cc dof/c_opt/opt (on the VAXs, at least)
4
$ dof == "$user:[abc1324.subdir]dof.exe"
(this is the path to your DOF.EXE file, must be
defined in this fashion, note the $ in the quotes)
5
DOF
(help is given)
-Eric
-----------------------------------------------------------#ifndef __DOF__
#define __DOF__ 1
#define C 0.000030
/* Fudge factor */
double doffront (
file:///C|/faq.html (55 of 555) [7/19/2002 3:46:24 AM]
double f,
double s,
double l)
{
double
x, y;
x = C * f * s * (s - l);
y = (l * l) + C * f * (s - l);
return (x / y);
}
double dofrear (
double f,
double s,
double l)
{
double x, y;
x = C * f * s * (s - l);
y = (l * l) - C * f * (s - l);
if (y <= 0)
return (0);
else
return (x / y);
}
#endif
-----------------------------------------------------------#include <stdio.h>
#include <stdlib.h>
#include "dof.h"
int main
{
double
double
double
(int argc, char *argv[])
f;
s;
l;
/* F number of lens */
/* Distance to center of shot, m */
/* Focal length of lens, mm */
double x, y;
int z;
if (argc
{
printf
printf
printf
printf
printf
printf
return
}
/* Internal use in this procedure */
/* Internal counter */
< 4)
("Usage:\n");
("\t%s f d l[...]\n", argv[0]);
("\nWhere\n\tf = f-number (ie, 2.8, 4, 8, etc)\n");
("\td = distance to subject in meters\n");
("\tl = focal length of lens in millimeters (ie 28, 50, 200)\n");
("\tOptionally, a series of lengths may be given\n");
(1);
file:///C|/faq.html (56 of 555) [7/19/2002 3:46:24 AM]
f = atof (argv[1]);
s = atof (argv[2]);
for (z = 3; z < argc; z++)
{
l = atof (argv[z]);
l = l / 1000;
x = doffront (f, s, l);
y = dofrear (f, s, l);
printf ("\nUsing an f-stop of %g and a %2.3fm lens, ", f, l);
printf ("a subject at %g meters:\n", s);
printf ("\tD.O.F. front: %g m\n", s - x);
if (y == 0)
{
printf ("\tD.O.F. rear: infinity\n");
printf ("\tD.O.F. total: infinity\n");
}
else
{
printf ("\tD.O.F. rear: %g m\n", s + y);
printf ("\tD.O.F. total: %g m\n", x + y);
}
}
return (1);
}
================================================================================
Note 18.04
-< Basic Stereo and Parallax Concepts >-------------------------------------------------------------------------------PARALLAX PRINCIPLES IN STEREO PHOTOGRAPHY
John Berkowitz
The subject is parallax or more specifically what we mean by same
in stereography. Below are crude ASCII graphics which depict the
situation.
L
R
L
R
A
B
x
is
is
is
is
is
x
A
B
the left eyeball
the right eyeball
a vertical rod at some distance
a taller but otherwise identical vertical rod a little further away
a dummy point so I can use small angle approximations later
This is a plan or top view; we are looking down on the top of the
viewer's head and at the upper ends of the rods. It may help if you
draw lines between each pair of real points and also a line between
x and L as well as x and B.
file:///C|/faq.html (57 of 555) [7/19/2002 3:46:24 AM]
Distances are designated by their starting and ending points.
For example, LR is the interpupillary distance, usually around 65 mm.
Angles are designated by three letters, the vertex in the middle.
For example, the angles LRA and LRB are both 90 degrees.
>From the point of view of R, objects A and B have a common left edge.
>From the point of view of L they do not if L can detect angle ALB.
The detection of angle ALB is the crux of the matter, the heart of
the stereo effect.
This is probably a good place to mention that there isn't only one
kind of acuity associated with the human visual system. Normally when
we speak of acuity we are speaking of the ability to, say, separate
closely-spaced fine black lines on a white background. In this sense
of acuity, the best eyes can resolve about half a minute of arc and notso-good eyes, two minutes of arc. Usually one assumes the figure is one
minute of arc. In stereo or vernier acuity (vernier acuity is the
acuity associated with lining up split lines such as on a vernier scale)
the figure is much smaller. Stereo or vernier acuity is assumed to
be around six seconds of arc though there is at least one recorded
instance of a person having three-second stereo acuity.
You can see from the diagram that if the distance RA becomes greater,
the distance AB must become much greater for the angle ALB to remain
detectable. Assuming angle ALB is 6 seconds of arc, what is the
relationship of AB to RA?
First, we convert 6 seconds of arc to radians and find that it is
2.9E-5 radians. So ALB = 2.9E-5.
ALB = ALx - BLx
but ALx = RAL and BLx = RBL
so ALB = RAL - RBL and we don't need the point, x, anymore.
RAL = arctan LR/RA
RBL = arctan LR/(RA+AB)
IF RAL and RBL are small angles measured in radians, we can say,
approximately:
RAL = LR/RA
and
RBL = LR/(RA+AB)
So: ALB = 2.9E-5 = LR/RA - LR/(RA+AB)
solving:
2.9E-5 = [LR(RA+AB) - LR*RA] / [RA(RA+AB)]
Since AB<<<RA, we can ignore the AB in the term (RA+AB) and solve getting:
2.9E-5 = [(LR)(AB)]/(RA)^2
file:///C|/faq.html (58 of 555) [7/19/2002 3:46:24 AM]
Therefore:
AB = 2.9E-5 [(RA)^2]/LR
QED
So the minimum detectable displacement, AB, along the line of sight
at distance RA is 2.9E-5 times the square of the range, RA, in meters
divided by the interpupillary distance of .065 meters.
John Bercovitz
([email protected])
-----------------------------and to follow up on John's posting Stephen Spicer writes:
-----------------------------From: [email protected] (Stephen Spicer)
[Stuff deleted]
>Therefore:
>
>AB = 2.9E-5 [(RA)^2]/LR
-----------------------------------------------------------------------------If the approximation above regarding RAL and RBL is not made then:
ALB = 2.9E-5 = (arctan LR/RA) - (arctan LR/(RA+AB))
Solving this we get, step by step:
tan(2.9E-5) = (LR/RA) - LR/(RA+AB)
LR/RA - tan(2.9E-5) =
LR/(RA+AB)
LR
-------------------LR/RA - tan(2.9E-5)
AB =
- RA
(Where LR = 0.065m normally)
In this relationship, AB goes to infinity when the bottom line goes to zero.
ie: AB is infinte when
LR/RA - tan(2.9E-5) = 0
Solving this for RA we get
RA = LR / tan(2.9E-5)
file:///C|/faq.html (59 of 555) [7/19/2002 3:46:24 AM]
= 0.065 / tan(2.9E-5)
RA = 2236 meters
---------------In other words, normal vision should be able to perceive the parallax
between an object A at range 2236m, and object B at a distance of
"infinity". I think that this is a little more than the figures I have
heard previously. It does of course depend on what you assume for the value
of stereo acuity (6 seconds of arc used above)
The only reason for working this through without the assumptions was that
John Bercovitz's posting got me thinking about all this.
Now I'll just put that final equation for AB into my spreadsheet and plot
me a handing graph to show the neighbours.....
Steve Spicer
Melbourne, Australia
(I hope my algebra is OK, I just don't have time to double check this
before posting!)
================================================================================
Note 18.05
-< More Advanced Stereo Concepts and Stereo FTP site >-------------------------------------------------------------------------------MORE ON STEREO PARALLAX
also, at end, instructions on FTP info on stereo stuff
by John Berkowitz
I also wanted to talk a little about the effects of not maintaining
ortho conditions in stereo photography. I think an intuitive way into
this may be to first discuss the effects of binoculars on stereo perception.
The usual binoculars (the models which use Porro prisms as erectors)
do two things: they magnify and they increase the separation of the
eyes.
Going back to our sketch:
L
R
L
R
A
B
is
is
is
is
A
B
the left eyeball
the right eyeball
a vertical rod at some distance
a taller but otherwise identical vertical rod a little further away
>From this sketch I previously derived:
AB = 2.9E-5 [(RA)^2]/LR
where:
AB is the smallest separation which can be detected at range RA.
file:///C|/faq.html (60 of 555) [7/19/2002 3:46:24 AM]
2.9E-5 is the tangent of 6" of arc which is a figure for stereo acuity
The first thing binoculars do is to magnify the angle ALB.
This makes
the eyes sensitive to a smaller angle. So the new angle which can be
detected is ALB/M where M is the magnification of the binoculars.
The second thing binoculars do is to increase the distance LR.
angles, doubling LR doubles ALB.
For small
So let's say that LR is doubled and M = 7. How far away can you now
see what separation? I suppose we need a new variable, S, which will
be the separation of the binoculars' objectives divided by the separation
of the eyes (65 mm). In the present case, then, S = 2. Taking these
effects into account, our modified formula becomes:
AB = 2.9E-5 [(RA)^2]/(LR*M*S)
So we can see a separation which is 1/M*S or 1/14th of the separation
which we can perceive with our unaided eyes. If we could in practice
separate something which was at 350 meters from the infinite background,
with the aid of binoculars we can now separate something which is at a
distance of 14*350 = 4900 meters.
The next questions are "What is the effect of the increased separation
of the points of view when using binoculars?" and "What is the effect of
increased angular magnification when using binoculars?".
The increased separation of the points of view may be thought of as giving
a giant's view of the world. A giant would see the world same as you or I
but everything would appear smaller relative to his size. That's why when
you take pictures of scenes with widely-spaced cameras, you get a Lilliputian
version of the scene. I realize that wasn't terribly rigorous. 8-)
I've drawn a sketch of how the geometry causes this. It's in the photo-3d
ftp directory as "ortho.sep.ps.Z". You can see from the sketch that
increased camera spacing gives an exact reduced model of the scene. The model
is reduced in depth, width, and height. So the reduced-size objects appear
nearer. This means that height & width of a reduced object subtend the same
angles at the viewer's eyes as the full-sized object would.
The other problem is that of magnification. Magnification causes an
apparent decrease in the depth of objects in the scene and also of
course a decrease in the distance from object to object along the line
of sight. (Non-sequitur: Is this what would happen if you were looking
along the line of motion if you were approaching the speed of light?)
Sorry. 8-) There is a companion sketch in the ftp directory called
"ortho.magn.ps.Z" which demonstrates the problem. Usually in stereo
photography we have the opposite problem, demagnification, when we
are viewing. This is because it is easier to find a camera lens which
puts a wide coverage on the negative than it is to find a viewing lens
which will cover that angle. The upshot is that most stereo cameras'
taking lenses are 35 mm focal length while most viewing lenses are 50 mm
focal length for a demagnification of 35/50 = 0.7. The effect here is
to stretch the object along the line of sight from the viewer to the
reconstructed object. The apparent size of the object in height and
width does not change but the apparent distance to it changes. The actual
file:///C|/faq.html (61 of 555) [7/19/2002 3:46:24 AM]
angles subtended at the eye by the object's height and width do change,
of course; that is the essence of magnification. The apparent depth
increases by the factor 10/7.
If you care to look at the sketches, you get to the photo-3d ftp
directory as follows:
% ftp csg.lbl.gov
account <default>: anonymous
.., send ident as password... <put username here, won't echo>
<at this point you are logged in>
cd pub/listserv/photo-3d
<to get to our directory>
dir
<this shows list of what's there>
binary
<need this to transfer binary file>
get <filename> will transfer file to your home directory..
quit
At the present time the 3d directory looks like so:
1545
45512
54068
21237
203292
2324
19890
501655
201485
182768
184272
12041
423407
6040
Jun
Mar
Apr
Apr
Mar
Mar
Mar
Mar
Mar
May
Jun
Mar
Mar
Mar
2
29
12
12
11
5
5
18
25
4
17
9
17
9
1.index
3d-faq.ps.Z
3d.prod.serv
3d.prod.serv.Z
ES.CTD.ACHR.PS.Z
PStc.expl
PStc1.25.Z
archive_1.Z
dpthfld.ps.Z
ortho.magn.ps.Z
ortho.sep.ps.Z
photometry
raytrace.ps.Z
wratten.filters
"1.index" gives a description of the other files, as you might suspect.
John Bercovitz
([email protected])
================================================================================
Note 18.06
-< Photometry and Light Meters Primer >-------------------------------------------------------------------------------The Photometric System in General
followed at end with specific photographic references re: light meters
by John Bercovitz
Light flux, for the purposes of illumination engineering, is
measured in lumens. A lumen of light, no matter what its wavelength
(color), appears equally bright to the human eye. The human eye has a
stronger response to some wavelengths of light than to other
wavelengths. The strongest response for the light-adapted eye (when
scene luminance >= .001 Lambert) comes at a wavelength of 555 nm. A
file:///C|/faq.html (62 of 555) [7/19/2002 3:46:24 AM]
light-adapted eye is said to be operating in the photopic region. A
dark-adapted eye is operating in the scotopic region (scene luminance
</= 10^-8 Lambert). In between is the mesopic region. The peak
response of the eye shifts from 555 nm to 510 nm as scene luminance is
decreased from the photopic region to the scotopic region. The
standard lumen is approximately 1/680 of a watt of radiant energy at
555 nm. Standard values for other wavelengths are based on the
photopic response curve and are given with two-place accuracy by the
table below. The values are correct no matter what region you're
operating in - they're based only on the photopic region. If you're
operating in a different region, there are corrections to apply to
obtain the eye's relative response, but this doesn't change the
standard values given below.
Wavelength, nm
400
450
500
550
Lumens/watt
0.27
26
220
680
Wavelength, nm
600
650
700
Lumens/watt
430
73
2.8
Following are the standard units used in photometry with their
definitions and symbols.
Luminous flux, F, is measured in lumens.
Quantity of light, Q, is measured in lumen-hours or lumen-seconds.
It is the time integral of luminous flux.
Luminous Intensity, I, is measured in candles, candlepower, or
candela (all the same thing). It is a measure of how much flux is flowing
through a solid angle. A lumen per steradian is a candle. There are 4 pi
steradians to a complete solid angle. A unit area at unit distance from a
point source covers a steradian. This follows from the fact that the
surface area of a sphere is 4 pi r^2.
Lamps are measured in MSCP, mean spherical candlepower. If you
multiply MSCP by 4 pi, you have the lumen output of the lamp. In the case of
an ordinary lamp which has a horizontal filament when it is burning base
down, roughly 3 steradians are ineffectual: one is wiped out by interference from the base and two more are very low intensity since not much
light comes off either end of the filament. So figure the MSCP should be
multiplied by 4/3 to get the candles coming off perpendicular to the lamp
filament. Incidentally, the number of lumens coming from an incandescent
lamp varies approximately as the 3.6 power of the voltage. This can be
really important if you are using a lamp of known candlepower to
calibrate a photometer.
Illumination (illuminance), E, is the _areal density_ of incident
luminous flux: how many lumens per unit area. A lumen per square foot is
a foot-candle; a one square foot area on the surface of a sphere of radius
one foot and having a one candle point source centered in it would
therefore have an illumination of one foot-candle due to the one lumen
falling on it. If you substitute meter for foot you have a meter-candle
or lux. In this case you still have the flux of one steradian but now it's
spread out over one square meter. Multiply an illumination level in lux by
.0929 to convert it to foot-candles. (foot/meter)^2= .0929. A centimetercandle is a phot. Illumination from a point source falls off as the square
of the distance. So if you divide the intensity of a point source in candles
by the distance from it in feet squared, you have the illumination in foot
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candles at that distance.
Luminance, B, is the _areal intensity_ of an extended diffuse source
or an extended diffuse reflector. If a perfectly diffuse, perfectly
reflecting surface has one foot-candle (one lumen per square foot) of
illumination falling on it, its luminance is one foot-Lambert or 1/pi
candles per square foot. The total amount of flux coming off this
perfectly diffuse, perfectly reflecting surface is, of course, one lumen per
square foot. Looking at it another way, if you have a one square foot
diffuse source that has a luminance of one candle per square foot (pi times
as much intensity as in the previous example), then the total output of
this source is pi lumens. If you travel out a good distance along the
normal to the center of this one square foot surface, it will look like a
point source with an intensity of one candle.
To contrast: Intensity in candles is for a point source while
luminance in candles per square foot is for an extended source - luminance
is intensity per unit area. If it's a perfectly diffuse but not perfectly
reflecting surface, you have to multiply by the reflectance, k, to find the
luminance.
Also to contrast: Illumination, E, is for the incident or
incoming flux's areal _density_; luminance, B, is for reflected or
outgoing flux's areal _intensity_.
Lambert's law says that an perfectly diffuse surface or
extended source reflects or emits light according to a cosine law: the
amount of flux emitted per unit surface area is proportional to the
cosine of the angle between the direction in which the flux is being
emitted and the normal to the emitting surface. (Note however, that
there is no fundamental physics behind Lambert's "law". While
assuming it to be true simplifies the theory, it is really only an
empirical observation whose accuracy varies from surface to surface.
Lambert's law can be taken as a definition of a perfectly diffuse
surface.)
A consequence of Lambert's law is that no matter from what
direction you look at a perfectly diffuse surface, the luminance on
the basis of _projected_ area is the same. So if you have a light
meter looking at a perfectly diffuse surface, it doesn't matter what
the angle between the axis of the light meter and the normal to the
surface is as long as all the light meter can see is the surface: in
any case the reading will be the same.
There are a number of luminance units, but they are in categories:
two of the categories are those using English units and those using metric
units. Another two categories are those which have the constant 1/pi built
into them and those that do not. The latter stems from the fact that the
formula to calculate luminance (photometric Brightness), B, from
illumination (illuminance), E, contains the factor 1/pi. To illustrate:
B = (k*E)(1/pi)
Bfl = k*E
where:
B =
Bfl
k =
E =
luminance, candles/foot^2
= luminance, foot-Lamberts
reflectivity
0<k<1
illuminance in foot-candles (lumens/ foot^2)
Obviously, if you divide a luminance expressed in
foot-Lamberts by pi you then have the luminance expressed in
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candles /foot^2.
(Bfl/pi=B)
Other luminance units are:
stilb = 1 candle/square centimeter
apostilb = stilb/(pi X 10^4)=10^-4 L
nit = 1 candle/ square meter
Lambert = (1/pi) candle/square cm
sb
asb
nt
L
Below is a table of photometric units with short definitions.
Symbol
Term
Unit
Unit Definition
Q
light quantity
lumen-hour
lumen-second
radiant energy
as corrected for
eye's spectral response
F
luminous flux
lumen
radiant energy flux
as corrected for
eye's spectral response
I
luminous intensity
candle
candela
candlepower
one lumen per steradian
one lumen per steradian
one lumen per steradian
E
illumination
foot-candle
lux
phot
lumen/foot^2
lumen/meter^2
lumen/centimeter^2
B
luminance
candle/foot^2
foot-Lambert
Lambert
stilb
nit
see unit def's. above
(1/pi) candles/foot^2
(1/pi) candles/centimeter^2
1 candle/centimeter^2
1 candle/meter^2
=
=
=
=
Note: A lumen-second is sometimes known as a Talbot.
To review:
Quantity of light, Q, is akin to a quantity of photons except
that here the number of photons is pro-rated according to how bright
they appear to the eye.
Luminous flux, F, is akin to the time rate of flow of photons except
that the photons are pro-rated according to how bright they appear to the eye.
Luminous intensity, I, is the solid-angular density of luminous flux.
Applies primarily to point sources.
Illumination, E, is the areal density of incident luminous flux.
Luminance, B, is the areal intensity of an extended source.
Photometry with a Photographic Light Meter
The first caveat to keep in mind is that the average unfiltered light
meter doesn't have the same spectral sensitivity curve that the human eye
does. Each type of sensor used has its own curve. Silicon blue cells aren't
too bad. The overall sensitivity of a cell is usually measured with a
2856K or 2870K incandescent lamp. Less commonly it is measured with
6000K sunlight.
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The basis of using a light meter is the fact that a light meter uses
the Additive Photographic Exposure System, the system which uses
Exposure Values:
Ev = Av + Tv = Sv + Bv
where:
Ev
Av
Tv
Sv
Bv
=
=
=
=
=
Exposure Value
Aperture Value = lg2 N^2
Time Value = lg2 (1/t)
Speed Value = lg2 (0.3 S)
Brightness Value = lg2 Bfl
where N = f-number
where t = time in sec.s
where S = ASA speed
lg2 is logarithm base 2
from which, for example:
Av(N=f/1) = 0
Tv(t=1 sec) = 0
Sv(S=ASA 3.125) E
Bv( Bfl = 1 foot-Lambert) = 0
and therefore:
Bfl = 2^Bv
Ev (Sv = 0) = Bv
From the preceeding two equations you can see that if you set the
meter dial to an ASA speed of approximately 3.1 (same as Sv = 0), when
you read a scene luminance level the Ev reading will be Bv from which you
can calculate Bfl. If you don't have an ASA setting of 3.1 on your dial, just
use ASA 100 and subtract 5 from the Ev reading to get Bv.
(Sv@ASA100=5)
Image Illumination
If you know the object luminance (photometric brightness), the
f-number of the lens, and the image magnification, you can calculate the
image illumination. The image magnification is the quotient of any linear
dimension in the image divided by the corresponding linear dimension on
the object. It is, in the usual photographic case, a number less than one.
The f-number is the f-number for the lens when focussed at infinity - this
is what's written on the lens. The formula that relates these quantities is
given below:
or:
where:
Eimage = (t pi B)/[4 N^2 (1+m)^2]
Eimage = (t Bfl)/[4 N^2 (1+m)^2]
Eimage is in foot-candles (divide by .0929 to get lux)
t
is the transmittance of the lens (usually .9 to .95 but lower
for more surfaces in the lens or lack of anti-reflection
coatings)
B
is the object luminance in candles/square foot
Bfl is the object luminance in foot-Lamberts
N
is the f-number of the lens
m
is the image magnification
References:
G.E. Miniature Lamp Catalog
Gilway Technical Lamp Catalog
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"Lenses in Photography" Rudolph Kingslake Rev.Ed.c1963 A.S.Barnes
"Applied Optics & Optical Engr." Ed. by Kingslake c1965 Academic Press
"The Lighting Primer" Bernard Boylan c1987 Iowa State Univ.
"University Physics" Sears & Zemansky c1955 Addison-Wesley
Acknowledgements
Thanks to John Bercovitz for providing the material on photometry and
illumination. Thanks to Andy Young for pointing out that Lambert's
law is only empirical. Thanks to John Bercovitz, donl mathis, and
Bill Tyler for reviewing an earlier version of this file. I've made
extensive changes since their review, so any remaining bugs are mine,
not a result of their oversight. All of them told me it was too
detailed. I probably should have listened.
Copyright (C) 1993, 1994, 1995 David M. Jacobson
Rec.photo.* readers are granted permission to make a reasonable number
electronic or paper copies for their themselves, their friends and
colleagues. Other publication, or commercial or for-profit use is
prohibited.
================================================================================
Note 18.07
-< More on Polaroid Transfer Process >-------------------------------------------------------------------------------Questions and Answers: Polaroid Transfer Process
What is a polaroid transfer process ?
This is a process that transfers a polaroid image from the polaroid
film sheet to art paper. The procedure is to take a polaroid picture, start the
processing, peel the backing paper after about 10 seconds, place the developing
image onto damp art paper, rub / roll the image for 1.5 to 2 minutes and slowly
peel the film. What is left on the paper is a color dye image.
What kind of film can I use ?
It's the color dye that makes the transfer work. B&W doesn't transfer.
Use the "9" films such as 59, 669, ...
for making transfers.
For 3x4, it's type 668/669 or the new Polacolor 100. Polacolor 100
has more vivid colors than the other two. For 4x5, it's type 58/59
sheet film, or 558/559 4x5 pack film.
The 64T also works, but it's a Tungsten film.
use is type 809. It costs about $10 a sheet.
For 8x10, the film to
Integral (600) films do not transfer.
How long do I process before peeling the backing paper ?
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Time ranges from 5 seconds to 30 seconds.
Polaroid seggests 10 seconds. The best time will
be the result of your experimentation !
Some say the longer you wait before peeling the film apart,
the more likely the emulsion will lift off. Of course, lift off
could also be a desired effect.
Choosing the time to pull apart the packet is quite
critical, after 10 seconds most of the red is transferred to the backing
paper.
If the film develops longer than 10 seconds, colors in the transfer will
be less saturated. Not necessarily bad. Some have gotten good images
after a deliberate wait of 30 sec.
What kind of paper should I use and what do I do ?
Hot pressed watercolor paper is probably the best bet for a
transfer surface. Warm temperature is claimed to be a
help. Some people soak the paper in hot water. You could use a hot
lamp over your work surface to keep the surface warm.
Light tones are easiest to transfer. Hot press gives you a
sharper higher quality image, naturally it's more expensive.
Some use wet rice paper with good luck.
Then you need just the right amount of moisture.
Make sure your paper is not too wet.
How about filters and color bias ?
Many people use filtration to correct the imbalance;
Polaroid suggests this in their literature.
You can't expect perfect colors, or even close to perfect.
It just doesn't work that way.
The process has a built-in cyan color bias. Polaroid recommends
a CC20R filter (I think) If you use a strobe flash, any kind of
warm filter over the flash will help. If you are in a hurry and
don't have filters, use incandescent lights (yeah, 60-100 watt
household lights) This doesn't give true color, but if you want true
color you shouldn't use the transfer technique. If you use incandescent
lights, beware that reciprocity failure sets in quickly with this
type of film, compensate accordingly if your exposures are longer
than 1/15 sec.
Tip: Use a 30 magenta filter on your lens.
(it really helps the color)
Magenta filtration will help the "whites" somewhat..
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Some people use a 20cc magenta or red filter to
correct the blue cast. You can also try to peel earlier.
How do I peel, place, roll and lift ?
When making the transfer, press the film snugly against the transfer
sheet. You will find that repeated pressing with the palm
of you hand can work fine. Transfer for about 1 1/2 minutes before
peeling the film sheet away.
*******************
1. Place neg on transfer paper quickly and carefully
(I use dry paper to transfer to, rather than wet,
it tends to be sharper)
2. Use a rubber roller to bond the negative to the
transfer paper. (it takes about a minutes worth
of constant even pressure) You'll aquire the skills
quickly.
3. Let the transfer develop for about two minutes, then
pull the negative away VERY SLOWLY.
********************
Give a couple of rolls with a rubber roller (the type used for
printing wood cuts) and then burnish with a wad of dry paper towel
(you could use and soft ball of stuff).
Peel apart very gently and slowly, and PRESTO! a transfer print.
********************
One trick I picked up from the Polaroid reps is to roll the roller 2-3
times, then turn the whole assembly over and rub the back of the paper
with your hands in a circular motion. The heat from your hands
supposedly helps the transferring process.
********************
Polaroid suggests that heavy pressure on dark areas is desireable,
as it helps prevent the dark areas from peeling up. Polaroid even
suggests rubbing those areas (with the back of a spoon?) to prevent
peel up.
It doesn't work, now what ?
Don't be discouraged if you get part of the image lifted off in
the first few tries, or not much transfered at all.
Experiment !
The colors aren't correct, what did I do wrong ?
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Probably nothing. Don't use this process if you want perfect colors.
Tips ?
Have lots of paper towels and water to clean up with.
Transfers can be real messy!
**********************************
Compiled by:
[email protected] (Doug McFarland)
from messages sent by:
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
(Ty Monson)
(Greg Parkinson)
(Dan Sinclair)
(Brian Segal)
(Don Smith)
(Helen X. Qian)
================================================================================
Note 18.08
-< Tailflash Synchronizer Circuits >-------------------------------------------------------------------------------Tailflash synchronizers permit firing an electronic flash at the
end rather than at the beginning of an exposure as is usually the
case. Their purpose is to make a sharp picture due to electronic
flash exposure next to a blurred one caused by a relatively long
tungsten exposure. Tailflash synchronizers make the blur appear
in the correct position with respect to the sharp image.
4 PART TAILFLASH SYNCHRONIZER FOR LEAF SHUTTER CAMERAS
-9 volt ----------------------------------------------------.
.__________. |
.--------------------------.
.____| 180 ohms |__*_____>
| 16 15 14 13 12 11 10 9 |
|
|__________|
|
|
*------------------------>
|
IC 4049
|
|
.-------------.
|
|
'----| Cathode
|
| 1 2 3 4 5 6 7 8 |
.----|-------------|----->
'--|--|--|--|--|--|--|--|--'
'----| Anode
|
| | | | | | | |
|
C106D SCR |
| | *--|--*--|--*--|-------------| Gate
|
| |
|
|
|
|_____________|
| |
|
|
|____________________________*____>
| |
|
|
.__________.
|
+9 volt ___*__*_____*_____*___________________| 10 Kohms |___|
|__________|
to shutter
to flash
to flash
to shutter
Note: On IC 4049 pins 9-16 are not connected to anything. Use a 16 pin IC
socket rather than soldering to IC leads directly.
Note: SCR output is polarized and if flash does not work one way try reversing
connections. SCR must be able to deal with 250 volts or so.
Other suitable SCR's are: CR3CM, 54003LS3 and BRY55 (nice, compact unit)
Note: * signifies connection
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Note: When connecting flash to device it should fire. Wait a while and then
close the connection between the two shutter contacts. Nothing should
happen when you do this. When you disconnect them, however, flash should
fire. Shutter speeds shorter than 1/15 second may not work.
EDGE DETECTOR TYPE TAILFLSH SYNCHRONIZER CIRCUIT FOR LEAF SHUTTERS
.............
.............
+9 volt ----| 6.8 Kohm |----*----| 6.8 Kohm |-------------------> to shutter
|___________|
|
|___________|
|
..............
|
|
Anode|------------------> to flash
|
|
Cathode|--------------*---> to flash
._____________________|
|C106D SCR
|
|
|
|
Gate|----.
|
|
.............
|____________|
|
|
*----| 1N4148 | |----.
.________|
|
|
|_________|_|
| ........
|
|
|
.............
| |
|
| .............
|
:____| 470 Kohm |____*__| .1uF |___*__| 6.8 Kohm |___*
|___________|
|
|
|___________|
|
|______|
|
-9 volt ------------------------------------------------------*----> to shutter
Note: SCR output is polarized and if flash does not work one way try reversing
connections. SCR must be able to deal with 250 volts or so.
Other suitable SCR's are: CR3CM, 54003LS3 and BRY55 (nice, compact unit)
Note: * signifies connection
Note: Shutter speeds shorter than 1/15 second may not work.
Note: Connect to flash with female PC cord, to camera with male PC cord.
copyright 1993 - andrew davidhazy
non-commercial uses permitted
================================================================================
Note 18.09
-< Some aerial photography Tips >-------------------------------------------------------------------------------AERIAL PHOTOGRAPHY TIPS
Here are some tips from a photographer who posted them on rec.photo...
1.
2.
3.
4.
5.
6.
Use a high-winged plane.
Make sure the window on your side of the plane opens, some will,
some won't. The glass adds too much distortion.
Keep the horizon horizontal. Even if the horizon isn't in the
picture, by keeping it level the picture will make sense.
(note: vertical is ok, too... I'm just saying the pictures where
I held the camera at weird angles made me dizzy)
Shoot in the morning or evening. The additional shodows add depth to
the picture.
Keep the camera out of the airflow, and ton't touch the aircraft
with your upper body. It'll help you hold the camera steadier.
Carry lots of film... it's expensive to drop into your local
file:///C|/faq.html (71 of 555) [7/19/2002 3:46:24 AM]
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
grocery store to buy more. (pocket may be better than camera bag.
Discuss communications with your pilot. What works for us is for me
to explain what I want to take a picture of and from what
side. He then fly's by and I get a picture (only one is really
good since only at an instant am I exactly perpendictular.)
I usually then tell him to get farther from the subject, or
closer and do it again. It is best for me to tell him what to
do. I tried asking him and get "I'm not the photographer".
The person I fly with uses the trips to learn better aircraft
control. He enjoys my directions and practices to maintain them
as exactly as possible.
Focus on infinity, and have the lens focused before the shot appears.
You won't have time to focus and shoot when the decisive moment
comes.
I like the 100mm range for focal lentgh. A zoom was helpful. 35mm lenses
tends to get landing gear. My shutter speed was 1/2000, (100asa) and
there is some blur. I wouldn't want to enlarge much over 8x10.
I find aerial shots not very creative, but extremely fun. Although
the pictures might not be "artsy", people tend to look at them
for a much longer time than they do for even the most expensive
paintings.
Watch for fog, it is no fun, and the pictures show it! We have
rescheduled many flights.
Hail Mary's can be fun ( hold the camera out and point it straight
down and shoot) --- try one, but don't drop the camera.
Try pictures of your workplace or school. everyone is always
interested in finding their car, of building
If you really enjoy it, you can make money with aerial photography.
I've heard of several schemes, but havn't tried any yet.
If you want sharper pictures try renting a gyro-stabilizer. i've
never done it, but have had recommendations to the effect.
Have fun!
lee
-Lee McFearin.
[email protected]
#include <std/disclaim.h>
================================================================================
Note 18.10
-< Where to get film for SUBMINIATURE cameras >-------------------------------------------------------------------------------If you happen to need film for tiny cameras (such as the Minolta 16) that
use 16mm or Minox 9mm film here are two suppliers that may be of interest
to you.
1)
MicroTec Industries
P.O. Box 9424
San Diego,CA 92109
(619) 272-8820
They do processing of color and B&W Minolta 16 and minox films. Also they have
Minolta 16 bulk rolls (100ft) for $50. Their 18exp B&W is $5, color $6.
They also have lots of minox accesories, have then send you a catalog.
file:///C|/faq.html (72 of 555) [7/19/2002 3:46:24 AM]
2)
Minolta Processing Station
P.O. Box 2919
Torrance CA. 90510
They do processing of Minolta films and sell them. B&W 100 ASA for $3.50
with discounts on larger quanties.
The nice thing aobut the film canisters is that you don't have to destroy them
to get the film out. They just pop open. Once you have several on hand you
could get a bulk roll and probably be set for life as far as film goes.
...............................................................................
<I am looking for a source for Minox subminature film.
We are the American distributor for Minox and you can call us at (201) 808-9010
X 15 and we can direct you to the closest dealer. Or you can call our Minox lab
at (516) 437-5750 and they can help you. Or you can simply order it from any
local camera store. virtually any store in your area has an account with us for
Minox or one of our other lines.
Note 19.01
-< Making an Improvised Infrared Transmitting Filter >-------------------------------------------------------------------------------Visually Opaque, Infrared Transparent
I just determined what I had long suspected. I measured the spectral
transmission characteristics of one and two thicknesses of unexposed but
developed E6 films and found them to be comparable to that of a Wratten 87 IR
filter. In addition I also made some pix on HIE film through two sheets of D max
EF sheet film and compared the pix to some taken through a "standard" IR filter,
the Wratten 87.
The result of this is that it appears that one thickness of E6 film is roughly
the equivalent of an 87 filter but with a broader spectral response and with
some 1% transmission valleys at 500 and 600 nm. Its transmission starts to drop
from 1% at 700 nm to about 95% at 800 nm. Two thicknesses of D max E6 are
basically visually opaque with transmission dropping rapidly starting at 720 nm
and dropping quite rapidly to 90% or so at 850 nm.
Maybe they might be closer to what a 88 is. Basically the 2 sheets of E6 simply
do not have as steep of a cutoff as the Wratten filters do nor as good a
maximum transmittance. But they are serviceable!!! especially for placing over
a flashgun where expensive Wratten filters tend to fry and buckle!
Picture-taking wise, the two thicknesses of E6 film did not seem to degrade
image sharpness significantly when used with 4x5 format. I have not tested 35mm.
They would obviously not matter much when used over a flash for inconspicuous
flash photography at parties, etc.! (camera lens with or without additional
filter over it).
If you would like a copy of the spectral transmission curves for the 1 and 2
sheets of E6 film, and that of an 87 filter, just send me some e-mail along
with your RIT postal address. If you do not hear from me in a few weeks (!)
jog my memory.
Andy
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================================================================================
Note 19.02
-< Fishing for a lost Leader! >-------------------------------------------------------------------------------Reclaiming a Film Leader
There are many ingenious ways of trying to recover a film leader that for some
reason needs to be accessed after it has already been wound into the casette.
This is the start of such a list compiled from various sources.
..............................................................................
I just read a new film leader extraction tip that doesn't require the
special tool, which you might want to try. Take a disposable 4 frame (or
so) negative strip. Turn your partly used roll inside it's container a few
times in the rewind direction. Each time the leader passes the entry slot
you should be able to feel or hear a click. From this click you should be
able to figure out where the leader is. Turn the film until the leader is
on the opposite side of the roll from the entry slot. Now insert one end
of your negative strip into the entry slot about halfway (or as far as it'll
go, whichever comes first). Rewind the film until the leader clicks again.
Now insert the other end of the negative strip as far as it'll go (but leave
something out to hold onto). Turn the film in the "wind" direction
(ie, opposite of rewind) a little bit. Now pull slowly and steadily in the
negative strip, and hopefully the trapped leader will come out with it.
I haven't tried this myself yet so take it FWIW, but it sounds like it
might work. I think I'll try this out myself tonight.
From: "Stephen Wall (SFAE-AR-HIP-SY)" <[email protected]>
and here is another tip:
You might try this trick. Get some double stick tape or if you are in a
crunch use single stick tape and fold it over onto itself so that the
sticky side is facing out. Get a scrap lenght of film and place the tape
on the emulsion side of the scrap film. Turn the film cassette a few
turns so that it windes around the center spool tightly. Then insert the
scrap film with the double stick tape into the cassette. Turn the film
cassette the other direction so that the film in the cassette expands to
the outside surfaces of the cassette, this will put the leader into
contact with the double stick tape. Then pull the scrap film and leader
out. I have used this method and it works and it's cheap. The trick is
finding double or single stick tape when you need it. Something you can't
very well do in the middle of the woods. However if you make yourself one
of this things before hand it might come in handy when you need it.
From: Patrick Wong <[email protected]>
================================================================================
Note 19.03
-< Some Basic Infrared Photography Information >-------------------------------------------------------------------------------PRIMER ON INFRARED PHOTOGRAPHY
file:///C|/faq.html (74 of 555) [7/19/2002 3:46:24 AM]
Here is the FAQ sheet I put together when this interested me. It is now
winter and I haven't had the time, but I do intend to get around to it some
time when I have a little more time up my sleeve.
--------------------------------------------------------------------------Here is the long awaited summary of the responses I recieved about my post
on getting started with infrared photography. I received about 20-30
replies via mail and news which was about 60K before pruning and 30K after
pruning of headers and quoting. Most people seemed to have similar things
to say so I'm fairly confident about the accuracy of what is said here.
Firstly, thanks go out to most of the following people who I have grepped
from my IR mailbox. Think a couple of lucky people have snuck in because I
saved questions from them :) And if you are really confused, someone sent
me a digest of previous articles/replies on the subject of IR photography
so I may have got your name from there.
[email protected], [email protected], [email protected],
[email protected], [email protected], [email protected],
[email protected], [email protected], [email protected],
[email protected], [email protected], [email protected],
[email protected], [email protected], [email protected],
[email protected], [email protected], [email protected],
[email protected], [email protected], [email protected],
[email protected], [email protected],
[email protected]
Thank you one and all.
==========================================
Getting started with Infra-Red Photography
==========================================
What is Infra-Red Photography and why do I want to do it:
Infra-Red photography is the photography of infra-red light (IR). The
reflectance of infrared light is different than that of visible light for
certain objects. The chlorophyl in plants reflects a lot of IR and
rocks/buildings are apparently quite interesting photographed with IR
film. Results can be quite good, but by all accounts, a lot of effort and
wasted film may be required to get those few good shots.
The Tools of the Trade:
First you need a camera. IR film is available in 35mm rolls and up. The
film is apparently fairly grainy so if you are using 35mm, enlargements
over about 10x8" won't be feasible.
Next you need a light sensitive bag. IR film is sensitive to the visible
light spectrum as well as the IR spectrum. The plastic canister that holds
the roll of film is IR proof, but the film canister itself is only 'mostly'
IR proof. Loading the film in a cool dark room is best. Loading the film
in a light proof/IR proof bag is also good, but if all else fails, a number
file:///C|/faq.html (75 of 555) [7/19/2002 3:46:24 AM]
of respondents seemed to think that a relatively dark room was OK and that
you might find a bit of fogging on the first couple of shots.
You need a filter for your camera. The film is sensitive to visible light
and IR, so to increase the effect of the IR light int the photo, you must
filter out the visible light a bit (or totally). The filters you require
are any of the following types. A Wratten #25A seemed to be the most
commonly mentioned. It is a very dark red colour and lets through some
visible light. A #29 filter (Far Red) was also mentioned. When using
either of these filters, the focus point moves about half way from the
normal focus to the IR focus on your camera (usually a red dot or line to
the side of the normal focusing position). The other type of filter is a
#87 filter or #87C filter gel. These filters are opaque which as you would
imagine makes focusing a little bit difficult. For all IR photography it
seems the best idea is to turn off your autofocus, set up the shot and then
place the filter on the camera for your shot.
You need some IR film. General consensus was only buy film from places
that keep it refridgerated. Keep it cool until you use it. Use it quickly
and keep it cool afterwards. Process it within 1-2 days of exposure.
Different films have different characteristics. The Konica and the Kodak
being the most commonly mentioned. IR film will fog if you get it hot, so
don't leave your camera in the car in the middle of summer unless you want
a whole bunch of photos that look like photos of pea soup fog.
Quoting from [email protected]'s respsonse
> Quite true but the problem can be explained simply by looking at the spectral
> sensitivity curves for the two films. The Konica film basically dies out at
> around 800 nm while the Kodak HS IR film has sensitivity even slightly beyond
> 900 nm. The 87 Wratten filter spectral transmission curve will show that this
> filter allows little radiation to pass to which the Konica film is sensitive.
This was a response to someone's comment that using the times suggested for
Kodak film, gave him a blank negative on the Konica film. The Konica film
is less likely to fog, less fussy when being loaded, but also less
sensitive to IR light.
Where to get the above items? People suggested that professional photo
shops were about the only place that will stock most of those items. If
you go to photo shops that specialise in architechural photography you
should be able to find all of those sort of items.
Taking your photos:
Set up the shot as per normal. Focus the shot using normal light
conditions. Put your filter on and adjust the focus to the appropriate
point. Half way to the red mark for the #25 filter or all the way to the
red mark for the #87 filter.
The IR film is only really sensitive to reflected IR light so having a
strong IR light source is relatively essential. The sun is a very good one
of these, very cheap, but unfortunately highly unreliable. Plants reflect
lots of IR light and rocks are apparently very good too. Bracket your
photos. Come up with an approximation for your shot and go at least +/-1
and if you are rich, +/-2 as well.
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Approximations for exposures suggested were as follows.
[email protected]
If you are using Kodak film, the red 25A filter, and TTL metering, shoot at
ASA 200 and bracket about +/- 1 stop.
[email protected]
I use ASA 200 or ASA 100
[email protected] (speaking about the colour IR slide film available)
I also shot some other things with it, aperture/timing as a normal 100ASA film.
For the slide IR, the use of a dark yellow filter is essential. It cuts out the
blue tones (without it, all the slides get a really cold/bluish look. But it
has to be *dark* yellow... I use two filters (a Y2 (no brand) and a Cokin 001
(which is also a Y2 filter, ie strength 2)) now on the film I'm currently
shooting, and hope to get some interesting results from that.
But as a ground rule, bracket loads until you get the 'feel' of the film, use a
strength 4 yellow on the slide IR (I use Ektachrome from Kodak) shooting it as
a 100ASA film and dark red (Hoya have an excellent one there) for the b/w IR (I
think they recommend a 50ASA-ish exposure).
[email protected]
I find it best to set my meter for an ISO of 200 (even though Kodak suggests
ISO 50) and bracket +1, +2, -1, and -2 stops.
[email protected]
You also need to bracket your exposures. +/- 1 stop around the ISO 200
exposure (if you use TTL metering and a 25A filter) should suffice to start.
Getting the film Processed:
Your run of the mill 1 hour processing lab may not be able to do IR film in
a hurry. If you are using the colour IR film it is even harder. It was
suggested that a University lab where they use the film for research might
be a good place to try for that. For the B&W film you can process it
yourself using the following method, or a few phone calls to processing
labs should find you someone who can do it.
[email protected]
IR film is EXTREMELY sensitive putting into the film tank - and
to avoid unexpected fogging. Use
they said to rate the film at...
you have to be ultra-carfeul when
its worth processing as soon as possible
IP11 for 11.5 mins. I've forgotten what
damn it was improtant... sorry.
[email protected]
It is processed in your favorite B&W soup, so far as I know (I've only
ever done one roll myself, and I followed the directions on the sheet
and processed it in class using D-76).
[email protected]
IR Ektachrome is a false-color transparency film that uses the old
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E-4 process, instead of the current E-6 process. To find the stuff,
Books on the subject:
[email protected]
The handiest book I've found for photography is 3 inches by 6 inches
and will answer most of your questions. It even has addresses for
infrared processing. The title is: The Ultimate Photo Data Guide by
Richard Platt. I bought it at a Crown discount bookstore.
[email protected] & [email protected]
The Art of Infrared Photography by Joseph Paduano
Kodak also put out a number of Books on or related to Infrared Photography
which would help get started.
If you are interested in an article about how to practice IR photography
with an SLR in "action" situations you might like to get in touch with
[email protected] and ask him to mail the information for
finding a copy to the FAQ maintainer for placing in the FAQ. I should
probably have already mailed him, but I've been busy and want to get this
done.
--------------------------------------------------------------------------That about finishes what I think I need to know to get started and as soon
as I have some spare time I will actually get onto it. I hope this helps
some of you get started as well.
From: [email protected] (Craig Richmond - division)
Organization: The University of Western Australia
================================================================================
Note 19.04
-< Checklists for Wedding Photography >-------------------------------------------------------------------------------THREE WEDDING CHECKLISTS FOR THOSE OF YOU WHO MAY
SOMEDAY BE CALLED UPON TO PHOTOGRAPH ONE
Make sure you discuss with bride and groom any special situations,
guests, customs, etc. that they particularly want to be photographed. A
wedding is a unique event in their lives and you will be providing a
very important service. Presumably you will also be paid well for the
role you will play during that day. Make sure to dress and conduct
yourself in a professional, dignified and unobtrusive manner. Also, you
will find that you may have to take on the role of master of ceremonies
especially during the reception if you expect every scheduled event to
happen like clockwork and not all at the last minute and hurried. With
time everyone will become more disheveled and casual. If by then you
have not yet taken the "formal" shots you will be hurting! There are
many labs that will print your negatives for a reasonable price so that
your profit on a wedding can be substantial. Labs often advertise in
magazines such as The Rangefinder (a magazine mostly dedicated to
wedding photography) or the Professional Photographer, the official
journal of the Professional Photographers of America.
file:///C|/faq.html (78 of 555) [7/19/2002 3:46:24 AM]
LIST NUMBER ONE...........................................................
HOUSE:
Bride getting ready
Bride alone formals
Bride with attendants
Bride with parents
CHURCH:
Groom pre-ceremony sequence
Groom with ushers
Groom with his parents
Processional coverage
Ceremony pix
Church double exposures
Bride with immediate family
Bride's parents (together and alone)
AV, bounce vignette of bride/attendants
Bride leaving house
Recessional coverage
Receiving line (candids)
Rice throwing
Car sequence (including signs on car)
Picture of the church
BRIDE& GROM FORMALS AT THE CHURCH, RECEPTION
Bride and Groom with each set of parents
Bride and Groom with both sets of parents
Bridal party group
Bride with groomsmen
Bride with bridesmaids
Groom with bridesmaids
Groom with groomsmen
Bride and Groom formals at altar
Each couple with Bride Groom
Groom with mother father
Bride and groom with her family
Bride and groom with his family
Formals of each couple bridal party
Bridesmaids alone (if missed at the house)
Each attendant with escorts
RECEPTION COVERAGE
Cake (bounce and direct)
Receiving line
Announcement of parents/ bridal party
Priests saying grace
Best man giving toast
Bride and groom toasting each other
Table shots of the guests
Full head table
First dance/ dance sequence
Cake cutting
Double exp/silhouettes of Bride/Groom
Add'l formals Bride&Groom
Band or D.J.
Candids of interest
Bouquet and Garther
Bride and Groom with couple that cought
Bouquet and Garter
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Bride-Groom goodbye pix
Picture of hall, names on marquee
Special effects (stack roll) old fashioned
THIS IS LIST NUMBER TWO (with spaces to add your own items?) ............
1 -____________________________________
-Bride at mirror with lipstick
-Bride at mirror - maid with headpiece
-Bride and mother at mirror
-Bride with invitation
-Bride coming down stairs
-Bride with attendants (informal)
-Bride with attendants arranged
-_____________________________________
10 -Bride with attendants and garter
-Bride with parents arranged
-Bride being kissed by parents
-Bride with family
-Bride with maid or mother with gifts
-Bride putting veil over face
-Leaving house - Group - arranged
-Bride and father leaving
-Getting in car - home in background
-_____________________________________
20 -Bride in car - demure expression
-Bride and Father in car smiling
-Cars arriving at the church
-Bride getting out of car
-Bride, attendants, father entering church
-Bride being given bouquet
-Pinning corsage on mother
-Pinning boutonniere on father
-Groom, Best man, and cleryman
-_____________________________________
-_____________________________________
30 -Best man adjusting Groom's boutonniere
-Processional lineup
-Procession
-_____________________________________
-Bride and Father arriving at the altar
-Father kissing Bride
40 -Groom kissing Bride
-Bride and Groom at altar
-_____________________________________
-Ceremony - side view
-Ceremony - Back of church (without flash)
-Church interior during ceremony
-Bride placing bouquet on altar
-Bride and groom receiving congrats
-Bride and Groom kissing at altar
-Bride and groom coming down aisle
50 -Groom kissing Bride at back of Church
-Bride and Groom congratulated by family
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60
70
80
90
100
-Bride and Groom congratulated by attendants
-Bride and Groom congratulated by friends
-_____________________________________
-_____________________________________
-_____________________________________
-_____________________________________
-_____________________________________
-Group pictures on altar
-_____________________________________
-Bride and Groom full
-Bride and Groom looking at each other
-Bride and groom close-up
-_____________________________________
-Bridal party arranged
-_____________________________________
-Bride, Groom with Brides parents
-Bride, Groom with Groom's parents
-Bride, Groom with both parents
-Bride, Groom with Grandparents
-_____________________________________
-_____________________________________
-_____________________________________
-Bride and groom leaving church
-Throwing rice at bride and Groom
-Bride and Groom getting in car
-Bride and Groom in car kissing
-Bride and Groom in car smiling
-Bride and Groom looking out back window
-Overall procession (auto)
-Wedding breakfast, over all setting
-_____________________________________
-Bride and Groom toasting
-_____________________________________
-Special customs
-_____________________________________
-_____________________________________
-_____________________________________
-Group pictures at reception
-Receiving line at reception
-Informals of receiving line
-Overall view of reception setting
-Informal shot of guests in general
-____________________________________
-____________________________________
-____________________________________
-____________________________________
-Cake alone
-Grand march
-Bridal toast - by best man
-Bridal table
-Family tables
-Guest tables
-____________________________________
-____________________________________
-____________________________________
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-____________________________________
-Bride and Groom toasting each other
-Bride and Groom cutting cake
110 -Bride and Groom feeding each other
-Bride and Groom dancing
-Bride and father dancing
-Groom and mother dancing
-Bridal party dancing
-Guest dancing
-Bride and Groom and ring
-____________________________________
-Throwing bouquet
-Throwing garter
120 -____________________________________
-Bride and Groom changed
-____________________________________
-Bride and Groom and goodbye
-____________________________________
-____________________________________
-____________________________________
_I_N_F_O_R_M_A_T_I_O_N____S_H_E_E_T_
NAME : __________________________________________________________
STREET : ________________________________________________________
CITY: _______________________
STATE : _____________ ZIP:________
TELEPHONE : _____________________________________________________
(Date):__________________
(Coverage)___________________________
BRIDE DRESSING AT:________________________________________________
TIME OF DRESSING:_________________________________________________
CEREMONY AT:______________________________________________________
TIME OF CEREMONY:_________________________________________________
GROUP PICTURES AT:________________________________________________
________________ : _______________________________________________
________________ : _______________________________________________
_N_A_M_E_S_
BRIDE : ________________________ GROOM : _________________________
MATRON : _______________________ BEST MAN : ______________________
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ATTENDANTS : ___________________ USHERS : ________________________
___________________
________________________
___________________
________________________
THIS IS LIST NUMBER THREE...................................................
Formal portraits
- bride and groom together in a studio. It's also popular to shoot
romatic poses in casual clothing at a scenic, outdoor location.
Wedding party
- combination of bride/groom, brides maid, best men, flower
girl, ring bearer, etc.
Ceremony
- father walking daughter on isle
- shot of entire stage
- shot of entire stage with various filters (star, soft, etc)
- exchange rings
- new couple liting candle
- signing marriage license
- kiss
- bride + groom walking down the isle
Reception
- head table
- cake cutting, feeding
- throwing garter
- throwing bouquet
- first dance
Miscellaneous
- bride arriving
- bride/groom leaving
- over threshold
- bride in make up room
WARNINGS:
MAKE SURE TO MEET WITH THE MINISTER, PRIEST OR RABBI AND DISCUSS WHAT IS ALLOWED
Weddings can be shot on 35mm although standard is 2 1/4. Standard wedding film
is Kodak VPS. Best to stick with one film. A second camera body is a definite
asset. Triopods are useful for some of the available light shots made during
the ceremony if this is allowed. Catholic weddings tend to be the most liberal
in terms of allowing access to good vantage points for photography. Even so it
may be wise to redo certain shots after the wedding.
file:///C|/faq.html (83 of 555) [7/19/2002 3:46:24 AM]
Have spare batteries in all shapes and sizes you need (AA batteries are
notorious for dying in the flash and button cells in the body!!!).
Some motor winders are very noisy and you may consider removing it during the
ceremony. A motor winder is a good source of AA batteries if your flash dies.
Slow (f:3.5) zoom lenses can be hard to focus in relatively dark reception
halls. f1.4 is easier to focus. You may consider using fixed focal length
lenses for this reason. Autofocus camera may also be useful to ensure sharp
photographs if used carefully.
lists compiled from postings in rec.photo on the usenet by andpph
================================================================================
Note 19.05
-< Standardized Mounting of Stereo Slides >-------------------------------------------------------------------------------Proper Mounting of Stereo Slides
The ANSI Standard PH3.11-1953 "Dimensions for Stereo Still Pictures on 35mm
Film 5 Perforation Format" gives the following dimensions (in inches):
For the camera transparency:
15 perforations between image pair centers, or 2.805 +/- 0.0075
Each pair of the exposures is between 0.915 to 0.935 wide
Each pair of the exposures is a minimum of 0.984 high (no maximum given)
For the mount:
Outside mount width is 4.000 +0/-0.018
Outside mount height is 1.625 +0/-0.016
Aperture centres are 2.438 +/-0.004
Film chip centers are 2.480 +/-0.004
( = 61.92mm +/- 0.1016mm)
( = 62.99mm +/- 0.1016mm)
(My copy of the standard is hard to read on these last two figures - anyone
want to volunteer to confirm these?) I quoted inches above as that is what
the standard uses.
As far as mounting gauges go, I personally don't like them. I have the Reel
3D gauge, it is well made with clear, thin lines, but I don't use it. We
obtain our mounts in Australia from a number of sources. Manufacturing
tolerances in the production of the mounts often results in the aperture
spacing being different from the two "near point" marks on the gauge. This
can result, under worst case conditions, in mounting a photo with images in
front of the window, even though the mounting gauge says it is OK.
The best thing to do IMHO (and I do mean in my humble opinion, as there are
many ways to mount) is to throw all gauges away. The next step is to cut a
mount in half through each aperture horizontally as you view through it.
This is your new 100% accurate gauge for the particular brand of mount you
are using. The distance between respective aperture edges is the near point
minimum distance when mounting IN THAT BRAND AND MODEL of mount. So now you
can position your cut-up mount anywhere on a stereo pair that you are
mounting to make sure that the near point is set to this distance:
file:///C|/faq.html (84 of 555) [7/19/2002 3:46:24 AM]
Near point distance
|
V
|
V
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
---------------|
|______________________________________|
What about the far-point distance? This gauge cannot measure it. But I say
"so what". You have taken the photo already, mounted it with the near
points as close together as the gauge will allow, so what are you going to
do if the far point is beyond infinity (ie: more than 63.4mm). You can't
move the chips any closer together, so why measure the far-point?
If you have a photo with TO MUCH DEPTH in it you could: satisfy the near
point distance OR satisfy the far point distance, but not both UNLESS you
re-engineer the mount by reducing the aperture centers (ie: move the window
forward). One ad-hoc way to do that is to reduce the aperture width by
placing strips of tape down the outside of each aperture (see also
Ferwarda, "The World of 3D", Chapter 25-3, "Double Depth Method")
These days, I don't even use the mounting gauge described above, I use the
edge of the mount I am mounting in to tell if stuff is in front of the
window.
Alternativley, you can do lots of eye-excersises so that you can diverge
your eyes at will. When you have "rubber eyes" you don't need mounting
gauges, just left and right images positioned anywhere in space, and you
can still fuse them :-)
(My first smiley!)
Steve Spicer
[email protected] (Stephen Spicer, TRL, Melbourne, Australia)
================================================================================
Note 19.06
-< Wedding Photography - More Tips >-------------------------------------------------------------------------------Here are my recommendations for what to cover and how to shoot a wedding.
Donald Farra <[email protected]>
First place yourself in the Bride and Groom's situation, talk to them a least
a month before the wedding, find out from them what they expect to be
photographed. Ask the Bride what photographs she has seen from other weddings
that she would like to have taken at her wedding. Ask her what photographs
she did not like and why, add these to your "don't take list". Like wise ask
the Groom also. Talk to the families too. Since the mothers will want
certain family shots both separate and with the other family.
Make sure you are paid in advance at least two weeks before the wedding.
Create a contract with them stating what services (time in hours) and
photographs you will take and when you will give them the final product. It
should state the what if any breaks you will take where and when and if food
will be provided for you. The contract should state what money will be
file:///C|/faq.html (85 of 555) [7/19/2002 3:46:24 AM]
refunded to them if you cannot make it to the wedding or you miss it all
together. It should also cover the event that the wedding is called off or
delayed. The goal is to have no surprises on either end.
The list of photographs to be taken from the families and wedding party will
form the core of your photograph list.
You should be able to break down the list into three time zones, before,
during, and after.
The photo gear should be checked out and new batteries installed before the
wedding day. Part of the check out is running a roll of film through each
camera with and without a flash to verify the exposure system. Spare
batteries are a must. Also go to the church or wedding location at or around
the time the wedding will occur to spot any problem areas and take mental
notes for good outdoor or indoor shots.
The first one should be the shots taken before the wedding ceremony.
These include the rehearsal and the dinner, family get togethers at the
bride's home just before leaving for the church. Bride and Groom arriving at
the church. The best man straighten out the Groom's tie. Groom with his
mother and father in the dressing room. Groom with the best man and then with
friends. Bride with her mother straighten out her dress and attaching her
veil. Bride with her father and mother. Bride with the ring bearer with her
looking at the ring, maybe with some window light coming in from the side.
Bride with the Flower girl and ring bearer. Bride with the maid of honor and
then the with the Bride's party. Photographs of the Bride and Groom before
the wedding ceremony at the alter, then with their families. It is important
to get the alter shots before the ceremony. If the bride doesn't want the
groom to see her before the wedding then shot each of the group shots
separately.
The second group of photographs to be taken is during the ceremony itself.
This is the most important set of photographs to be taken so have at least one
backup camera. Hopefully you will be able to use a flash and be allowed to
move around during the ceremony. Take the standard shots that you always see
in wedding albums, photographs of the wedding party, groom, and bride walking
down the walk-way, father giving the bride away etc. Make sure they look up at
you when you take the shot, eye contact is good to have in the photo. Also if
you can shot the couple from behind the alter to show their faces during the
various phases of the wedding. Finally don't miss the first kiss as man and
wife.
Third and last is the post wedding pictures.
This section is broken up into two parts, the formal shots of the wedding
party before the reception and the other part is the reception itself. You
will have to work fast on the first part so as not hold up the reception. At
this point you will want to take all the formal group shots typically outdoors
at a romantic location. Included in this set are the Groom and Bride by
themselves, both close ups and distance shots to pick up on the location
effects (mood). The other shots are with the families. Shots Grandparents of
both families in the background next comes the parents then the bride and
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groom in the foreground is example of the type of photograph you may want to
take. The second part of this section is the reception. Here you will have
to work very fast to cover everything. The typical shots include the
reception line, the throwing of the flowers, with this one you will photograph
the bride in the act of throwing the flowers over her head but not releasing
them. Next have her repeat the throw this time you will be shooting behind
her to capture on film the young lady who catches the flowers. Do likewise
with the garterbelt and the groom. Also included in this set is the cutting
of the cake and the shot of the bride and groom feeding the each other the
first piece. A shot I like to take is the signing of the marriage
certificate, along with this get the couple hugging each other with the bride
holding the certificate behind his back with one hand and the other hand
making the OK sign. Don't forget to photograph the cake before it is cut and
the rest of the food. Photograph the bride and groom at their table and the
best mans toast to the bride and groom. Other photographs that should be
taken include the first dance. Be fast and loose, take shots of the guests at
their tables without them freezing up or turning away, take natural shots if
possible. Finally get the shots of the couple as they get into and drive off
to their honeymoon.
Then you are done and you can drop dead of exhaustion and try to remember that
phone number for the trucking school you saw on TV the night before.
================================================================================
Note 19.07
-< Using "flash" exposure to lower print contrast >-------------------------------------------------------------------------------CONTRAST IS EXCESSIVE - HOW TO FIX IT WITH FLASH EXPOSURE
OK, so you really blew it this time and made a once in a lifetime shot that is
WAY to contrasty. Even with a filter factor of 00 the print is dead. Fear not
my fellows, all is not lost:
Dilute your regular paper developer by adding twice the water you normally use
(I use Ilford mixed 1:10 normally, here I use it 1:20). Over expose your print
by one stop, that is twice the amount of light or time. See what happens! A
reduced contrast print after several long minutes in the bath.
This is not a mathematical thing, it's an art.
It's sure saved my butt a couple of times!
So be prepared to experiment.
from: Louis - [email protected]
Just another $0.02 worth - with extra high contrast negs, you can also
pre-flash the paper (if you have a timer with tenth-of-second capability). You
just put the paper in the easel with no negative in the carrier, and give it a
short (.x sec) exposure of white light, at a moderate f-stop. You need to test
this first, making a test strip or two to see what the threshold for each paper
is, and how much light gives you how much fogging, but the intentional fogging
you get does bring down the highlights when you re-expose the paper for the
actual print. Tricky, and very much a seat-of-the-pants operation, but it's
useful (IMHO).
from: the other Andy - [email protected]
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Another way to preflash is to
would have a density of about
1/100 th of the main exposure
adequate if you are trying to
use a Neutral Density filter. Typically these
2.0 and this will give an exposure which is
(which for some film materials is often quite
get "extra" film speed).
In enlarging the procedure would be to preflash with just the bare carrier in
place (no neg in carrier) with a particular ND value under the lens for the
same time that you will for the final print. Then remove the ND filter, place
the neg in the enlarger and proceed conventionally.
To get less of a preflash use a higher ND value, for more a lower. .3 change in
ND is the equivalent of one stop of aperture or time (of course the actual
response being subject to RLF or reciprocity law failure).
It might be interesting to preflash with one contrast filter but expose with
another. I wonder what exactly would happen to the characteristic curve if one
did this...
from: Andy [email protected]
There is a much more controllably method to "Flash", or pre-expose your B/W
photographic paper.
1.
Establish a print time and f/stop for your print.
2. Obtain a defusing screen paper such as Seal ColorMount Dry Mount Paper,
(or other material about equal density).
3. Use the diffusion screen as a "filter" under your enlarging lens, much
like a polycontrast filter, keep your negative in the enlarger, use the
same exposure time with the defusing screen as you have established for a
correct exposure for this print. After this exposure remove the defusing
screen and make your normal exposure without the screen, (there should be
two full exposures, one with the screen, one without).
You may need to make more then one exposure with the defusing screen or
less then a full exposure depending on what you want from your final print,
you can determine that with a test strip. The real beauty of this method is
the ability to totally control the "Flash" exposure without removing your
negative from the enlarger so you do not experience alignment problems.
With the correct density of a defusing screen, you will not see any image
being projected on your paper, just a faint even light.
from: Lawrence - [email protected]
Call me backward! I don't PREflash. I POSTflash. I place the negative in the
negative carrier, focus on a 'focus-sheet', insert the paper I will expose into
the easel, make the exposure, then remove the negative and flash the now
exposed paper using either Andys' method. By focusing and making the exposure
using the negative firts, there is less chance of the enlarger slipping
and causing a slightly out-of-focus print. Many enlargers have a tendence to
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'drift' from true focus if too much time elapses between focus and exposure.
Also, if you are cropping, the exact alignment would be very 'iffy' in the
scenario (boy, I hate that word) where the exposure of the negative is made
last in the sequence.
from: ???
I "post-flash" also, but I use a separate contact-printing box instead of
the enlarger for the non-image light source. After making the exposure, I
put the paper in the proofer face-up (emulsion AWAY from the light source,
so the paper base itself acts as an ND filter) and expose for a short time.
On the homebuilt proofer we have in the lab, that time can be up to 2.2
seconds.
By using an altogether separate light source for the non-image-forming
exposure, I don't have to disturb the enlarger at all, so I have no problems
with focus shifts and such, nor do I have to realign my easel for each
print. Also, since the proofer does not mask the paper borders as an easel
does, there is no problem with the paper shifting between the image and
non-image exposures (creating an offset area of "flashing", which can show
as light gray on the white borders.) Last but not least, it's quicker to do
than removing and replacing the neg carrier in the enlarger; this may not be
of consequence if you're doing one print on your own time, but it becomes
important when you're cranking out 200 prints that need preflashing and have
to be done by tomorrow morning for a customer.
from: Richard - [email protected]
================================================================================
Note 19.08
-< Reloading One-Use Cameras >-------------------------------------------------------------------------------How to reuse kodak disposable cameras without
having to spool out your film in a darkroom.
First you need to remove the outer cardboard box from the camera. There's a
little diagram on the plastic body itself telling you how to open up the camera
body. Only open the camera body if you are completely finished with your roll
of film. When you open the camera, you will discover on the right hand side,
a normal 35mm film cassette. Take it out and have it developed as you normally
would. On the left hand side there is a spool. Take this out and look at it.
You will notice that one end appears to have been melted. Put the spool down
on a tabletop with this melted end facing up. Next, take a large paper clip,
unfold one end and heat it up with a candle or a cigarette lighter until it
glows. Press the hot paper clip gently into the melted end of the spool so tha
t it forms a slot that you can fit a screwdriver in it to turn it. Once the
spool has cooled off and hardened, you are ready to reuse your camera.
Take a roll of film, same ASA and length as the roll of film that came out of
the camera (but use whatever brand you want...i use XP2) and put it in the
camera where the previous roll was. Feed the end of the leader into the spool.
Be sure that the leader is secure into the spool. Now, you will notice that
there is a sprocket on the focal plane of the camera. turn this to the right
until it stops completely. The shutter is now cocked. Put the film cassette
and spool in their respective places in the camera and close its back, but
don't put the cardboard box on it yet. On the top of the camera, near the
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shutter release, there is a hole with a goldish piece of metal in it. Take
a paper clip or a thumbtack, insert it in the hole, and push this piece of
metal all the way to the left and hold it there. Take a screwdriver and
wind the spool counterclockwise until it stops. Don't force it. Remove your
paper clip from the hole. Put the cardboard box back on the camera body and
secure the flaps with drafting tape (drafting tape is removable and leaves
no adhesive behind). When you are done with your roll of film, open your
camera and take your film out and have it developed normally.
suggestion from: Joseph Pitassi III
[email protected]
================================================================================
Note 19.09
-< What is DENSITY? >-------------------------------------------------------------------------------1. What is the definition of density?
2. Does density have a physical unit or is it a unit-less ratio?
When light is directed thru a negative, some of the light is
transmitted, and some reflected or absorbed. The transmitted light can
be expressed as a percentage of the total incident light, if for
example 4/10 is being transmitted, we say that the negative has a
"transmission" of 40% This "transmission" tell us "how clear" a
negative is. Since we are interested in knowing "how dense" a negative
is rather than how clear it is, we calculate the "opacity" of it, where
opacity is the reciprocal of "transmission". For the above example, the
opacity would be 10/4 = 2.5
"Density" is then defined as the common Log of opacity, 0.4 (aprox) in
our case.
As for "does it have a physical unit?" the answer is: as far as
photography is concerned it is expressed in "units of density", but
being a relation between 2 values that must be expressed in the same
unit, mathematically and physically speaking, it is a unit-less ratio.
From: [email protected] (Guillermo Penate)
================================================================================
Note 19.10
-< Discontinued Film Sizes @ Film for Classics >-------------------------------------------------------------------------------If you are looking for film to fit obsolete cameras or need
discontinued film sizes the follwing comany may be able to help.
Richard T. Haviland, Film for Classics, P.O. Box 486, Honeoye Falls, NY
(716) 624-4945
FILM:
Format
(Kodak)
101
116
616
127
Type
B&W
B&W
B&W
Color
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Price
12.00
11.00
10.00
7.50
Format
(Kodak)
103
118
127
620
Type
B&W
B&W
B&W
B&W
Price
13.50
12.00
5.00
6.50
14472
620
124
828
828
Color 7.50
122
B&W
13.00
130
B&W
4.00 or 2/7.00
Color 5.50 or 2/10.00
B&W
B&W
13.00
13.50
Notes: B&W films are ISO 21 Ortho copy film except for 127,
which is ISO 100 panchromatic Efke. 127 and 620 color film is
Kodacolor Gold 200. 828 color is 400 ASA professional film.
$2 spool rebate on 103, 116, 118, 122, & 124 spools.
127 slide film is color slide film is custom made (cut).
A minimum order is 40 rolls at $10.00 a roll
Note 20.01
-< Flash Sync Speed Question and Answer >-------------------------------------------------------------------------------reply on a question on sync speed
by Andrew Davidhazy [email protected]
Rochester Institute of Technology
>Sorry for the stupid question, but can someone explain exactly what
>"flash sync speed" is? Everyone's talking about it and I'm in the dark...
With Focal Plane shutter equipped cameras (typical of SLR cameras) the shortest
exposure time with which an electronic flash can be practically used is that
with which the distance between the leading and trailing curtains of the
shutter is equal to, or greater than, the full film gate dimension of the
camera measured in the direction in which the curtains move.
The problem arises because the electronic flash is a very short duration light
source.
At exposure times shorter than the X-sync speed the distance between the
curtains is less than the width of the image gate and thus one could only make
a partial frame exposure (limited by the distance between the curtain edges)
when an electronic flash is used as the light source. There was (is) only one
camera/flash combo that overcame this limitation and it's the Olympus OM-4T
with a special (F-280?) electronic flash that transforms itself into a very
high frequency stroboscope when used in the FP mode.
Since the exposure time with an FP shutter is equal to the distance between the
curtain divided by the speed at which they move past the film it is obvious
that given a particular distance between curtains (such as 36mm) one can
achieve shorter exposure times with curtains that move at a fast rate.
Actually the "flash sync speed" refers to the shortest exposure time that a
short duration electronic flash can be used without loosing part of the frame.
This exposure time includes not only the time it takes the curtains to move
from one side of the gate to the other but also an appropriate time for the
flash itself to burn plus possibly a bit of "manufacturing tolerance".
================================================================================
Note 20.02
-< Kodak Lenses - characteristics and applications >-------------------------------------------------------------------------------file:///C|/faq.html (91 of 555) [7/19/2002 3:46:24 AM]
Kodak Lenses
Here is a less than exhaustive, yet not too shabby explanation of some of the
lenses found on Kodak cameras through the years. Information from a 1953 Kodak
Data Book called "Kodak Lenses" and from a small book published in 1959 called
"Photographic Lens Manual and Directory."
KODAK EKTAR LENSES
Kodak Ektar lenses simply referred to Kodak's finest lenses. They never
referred to any particular lens formula (tessar type, gaussian type, etc.), so
it is easy to find Ektar lenses that differ in design and construction. There
were Ektar lenses made for still photography, for enlarging, for cine work and
for projection. All Kodak Ektar lenses for still photography focused as a
unit. They were supplied integral to cameras, separately in shutters and in
barrels (lens tubes without shutters)
Kodak Ektars for Small and Medium Format:
101mm
105mm
127mm
152mm
44mm
f4.5
f3.7
f4.7
f4.5
f3.5
in Synchro-Rapid 800 Shutter (4 element)
in Flash Supermatic Shutter (5 element)
"
" or Supermatic-S Shutter (4 el.)
"
" (4 element)
on Kodak Signet 35 Camera (4 element)
Kodak also sold Ektars, Commercial Ektars, and Wide Field Ektars in various
focal lengths mounted in various shutters for use on large format view cameras.
KODAK ANASTAR (Anastigmat Special)
These lenses were especially designed for use on amateur cameras like the Kodak
Tourist II and Kodak Flash Bantam. They employ simple front element focusing
and usually consist of 4 elements. These lenses approached Ektar quality at
generally used apertures and lens-to-subject distances. They included a 48mm
f4.5 (Bantam) and a 101mm f4.5 (Tourist II).
KODAK ANASTON (Anastigmat)
Kodak Anastons were also front cell focusing anastigmats usually having 3
elements. They were even more "amateur" than the Anastars. Anastars included
lower priced lens for:
Kodak Tourist II (f4.5 or f6.3)
Kodak Pony 135 and 828 (f4.5 or f6.3)
Only the f4.5 models were "Lumenized" (Kodak name for Mag. Flouride
coating)
KODAR and KODET anastigmats
Cheap lenses mounted on Duaflex and Tourist cameras. Typically these were f8
lenses. The Kodars were focusing lenses and the Kodet were fixed focus.
EKTANAR and EKTANON
These were 3 element lenses for 35mm cameras. They include:
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Ektanar 44mm f2.8
Ektanar 50mm f2.8
Ektanon 46mm f3.5
From: [email protected] (Paul D. Cotnoir) @ Worcester Polytechnic Institute
================================================================================
Note 20.03 -< Masking to change contrast esp. for Ilfochrome use >-------------------------------------------------------------------------------Masking 101
by Barry Sherman of Amdahl Corpration
What is a contrast reduction mask?
--------------------------------Put very simply, a contrast reduction mask is a b/w negative which is produced
from an original and is sandwiched with the original to alter contrast. Being
a negative it will be dark where the original is light and light where the
original is dark, thus lowering contrast.
Masking can get quite sophisticated, however. You can take a negative
contrast reduction mask, contact print it onto another sheet of film, getting
a positive, and use this as a contrast-increasing mask. You can use either
type of mask with b/w and color negatives as well as with color transparencies.
I have done contrast masking with color negatives and, while I haven't done
it, have the idea stored away for use with difficult b/w negatives. Why
mask with b/w negs when we have different contrast grades available? With
a little care it should be possible to produce masks which are clear except
for certain areas, where they'll affect contrast. Localized contrast control.
To date I've been able to do so using variale contrast papers and buring
different areas with different colors of light. But it's an example of
a potential use in b/w printing.
You can vary the overall density of the contrast reduction mask so that it
reaches down to the mid-tones or even to the shadows, thereby varying
where contrast will be altered.
In addition, you may at times make a mask which is used in making the final
mask. Several generations can be involved. More on this later.
Masking equipment
----------------Equipment can be simple or fancy. Basically, the equipment, if any, is
used for registering the original and the mask.
* Light box and
light box and
right. Mylar
This can just
loupe. After producing the original you lay them on a
use a loupe to line them up, taping them together when they're
tape, available in better photo shops works well for this.
about drive a person crazy.
* Condit Pin registration equipment. This is a set of equipment comprising
a punch, contact print frame and negative carrier. The punch punches
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little 1/16" holes in the edges of 4x5 or larger film. These holes are
used to align the original and the masking film in the contact print frame
and in the negative carrier.
Quite expensive. A typical setup costs about $1000 purchased new. I got
mine for $400 from a Shutterbug ad. It is without doubt the most useful
darkroom accessory that I've ever had. You can take the color analyzer,
Jobo, print washer, compensating developing timer, you name it. I can
improvise around these losses. Just leave me my Condit Pin Registration
setup.
Condit Mfg:
U.S. (203) 426-4119
* Wess Plastics makes some equipment (a duper and a registration punch/slide
mount system) that people have used with good success for working with
35mm.
Materials
-------* Film. Kodak Pan Masking Film is the standard. Comes in 4x5 and larger
sheets. How to use with 35mm or medium format? Cut a hole in a sheet of
junk 4x5 film and use mylar tape to attach the smaller original in the hole.
Kodak Pan Masking film is somewhat slower than Tmax 100 (mentioned for
comparison) I'd guestimate its speed at around 25 or so. While it's
reputed to be a low contrast material, testing has shown it to be about
the same as Tmax 100, except that it's developed for a short time in
dilute developer, thereby lowering contrast.
What's different is that it has no anti-halation backing. This allows light
to bounce around, softening the edges of the image. This is desirable,
producing what are called "unsharp" masks. Such masks are easier to register
show errors
in registration less than would sharp masks. Unsharp masks
are also reputed to increase the apparent sharpness of the print.
Pan Masking Film is usually a special order item and is not cheap.
mine from B & H or Adorama for about $75 per 50 sheet box.
I buy
Because of the expense I've been trying Tmax 100. It requires different
handling to produce the unsharp masks, but I think that it works just
fine. Only problem is the amount of effort required to remove the purple
stain, which is pretty tedious. Why Tmax 100? Because I have it lieing
around so it's handy.
Roll film can be used for masking 35mm or medium format. Tmax 100 is
certainly an option here. FP4, both in sheets and rolls, is popular as well.
Kodalith. Kodalith high contrast film is used for highlight protection
masks. More on this later. Very useful stuff to have around. Very
cheap. Something like $40 for 100 sheets of 4x5.
Kodak LPD4. This is a litho type positive film. Dunno how it works but
developed in any standard developer it yields a high contrast *positive*
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and
image. Yup. Positive. Useful in making highlight bump masks. More on
that later. This can be difficult to get hold of. Apparently it's
classed as a graphic arts item and most photo shops won't know what you're
talking about.
I ordered mine through the
Aperture Film Center
127 Main St.
Los Altos CA 94022
(415) 941-1500
I believe that they do mail order. The smallest size of LPD4 available is
8x10 in 100 sheet boxes. I paid $100 for mine and figure that what with the
400 sheets of 4x5 that it'll be cut up into, it's dirt cheap and that's
enough for most of the rst of my life.
Both Kodalith and LPD4 can be used with a red safelight.
I use one of the little "painted light bulbs" for this.
Nice convenience.
* Devlopers.
For developing contrast reduction masks using Pan Masking film or Tmax 100
I use HC110 diluted 1:11 from stock.
For developing Kodalith, used in highlight protection masks, I use either
HC110 diluted 1:11 if I want relatively low contrast, D11 undiluted for
most work and occasionally Kodalith RT (two part litho) for very high
contrast.
* Bleach
Often a highlight protection or other type of mask will have density in
unwanted areas. The answer is to bleach with Potassium Ferricyanide. I
just pour some in a 35mm film cannister, add water and apply with a cotton
swab. Several applications, alternating between applying the ferricyanide
and dunking in fixer to remove the bleached silver will completely remove
all silver from the areas being bleached, leaving clear film there.
* Diffusion material.
This is used either above the original or between the original and the
masking film when exposing the mask and increases the unsharpness of the
mask. I use some stuff called Duralene, which I believe to be used for
drafting purposes. It's like a sheet of plastic frosted on both sides. I get
mine at a local art store. I've tried tablets of "frosted acetate" but
found them abominable. One side was glossy and they attracted dust like
nothing I've ever seen. The Duralene doesn't. Duralene cost around $1.50
per 8x10 sheet but I've been using the same 4x5 piece for several months
now.
Condit Mfg also sells "Herculene" which I gather is similar.
Making a mask
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* Exposing the material.
Exposure is done as a contact print.
"sandwiches".
I use one of two different
Layers from top to bottom, top being closest to the light source:
diffusion material
transparency, emulsion up
masking film, emulsion up
or
transparency, emulsion up
diffusion material
msking film, emulsion up
I use the former sandwich when using Pan Masking Film with its inherent
unsharpness and the latter when using Tmax 100. I'm not completely
satisfied with the degree of unsharpness that I'm getting with the latter
sandwich and may try putting a layer of diffusion material between the
transparency and the light source or may try putting the masking film
smulsion down.
* Determining exposure and development.
Exposure is easy. Just experiment. With time you'll develop the ability
to guess exposure based on the appearance of the transparency. Don't forget
that these contrast reduction masks are developed to a low contrast. This
means that variations in exposure don't have a huge effect on density.
Bob Pace teaches a technique based on equating development time and exposure:
less development means more exposure and vice versa. I haven't found this
to be necessary. He also adjusts exposure based on the average density
of the original. I find that three exposure times suffice: one for a
thinner mask, one for an average mask and one for a heavy mask. The
thinner mask will have density only in the highlight areas. The average
one will have a little density in the mid-tone areas. A heavy mask will
have density going down to the lowest of the mid-tone areas.
For my enlarger and working conditions these are:
With Tmax 100
Thin
average
heavy
2 seconds at f32
4 seconds at f32
8 seconds at f32
With Pan Masking film
8 seconds at f32
8 seconds at f22
8 seconds at f16
Yours will vary, probably greatly. This is offered as a sample only.
Obviously I adjust based on how dense the original is, overall. I get the
mask right on the first try about 75% of the time.
Development can be more complicated.
gamma is defined as:
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The basic term used is "gamma" where
density_range_of_transparency - exposure_scale_of_printing_paper
---------------------------------------------------------------density_range_of_transparency
The calculated gamma will typically fall between 0.0 and .6 or so.
rule of thumb taught to me by Charley Cramer is that:
transparency contrast
low contrast
average
average
higher
high
really high
...
gamma
.1
.2
.3
.4
.5
.6
...
The
developing time in HC110 1:11
1 minute
2 minutes
3 minutes
4.5 minutes
5.5 minutes
7 minutes
...
Exposure scale of the paper is defined as the density range of an original
which will print with slightly less than total black (Dmax) and slightly less
than total white (Dmin). Two ways to determine the exposure scale of the
paper. Print a step tablet. Find the steps which are just lighter and
darker than Dmax and Dmin. The difference in density between the
corresponding steps in the original tablet is the exposure scale of the
paper.
Or you can just accept that Ilfochrome high contrast material has an
average exposure scale of ~1.75 when developed in P3 chemistry. Somewhat
higher if developed in P30P.
With a given transparency you can:
1)
Learn to judge the gamma required in the mask and to develop accordingly.
This is Charley's usual technique. He does stunning prints.
2)
Measure the lightest and darkest areas using a densitometer or a
baseboard light meter, calculate the gamma required and develop
accordingly. I use this approach, using my color analyzer as a
baseboard densitometer.
I've gone one step further. Having determined the density range of the
slide, I look at the step tablet print and decide which step represents
how I'd like the highlights to look and which step represents
how I'd like the shadows to look. Then I use the difference in
density between these steps in the original step tablet as the exposure
scale of the paper in calculating gamma. This has significantly
increased the number of masks that are right on the first try.
* Developing the mask
I just use 4x5 film trays and agitate constantly. Stop bath and fix as
normal. I give a quick rinse (often just dropping the mask in the Jobo
water bath for a minute or two), dip in distilled water with wetting
agent added and dry in a closet with an electrical space heater running.
I've tried blow drying masks but they seemed to shrink somehow as they
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never registered quite right when dried this way.
Printing with masks
------------------Very simple. Just register the mask with the original and print. The
mask goes on top of the original, closest to the light source. Expect
exposure times to go up significantly. Probably around 1-2 f-stops.
Additional masking
-----------------Ilfochrome has a fairly pronounced toe to its characteristic curve. I.e. not
a lot of contrast. And transparency films have the same. So highlight
contrast, or lack thereof, can be a problem even without masking. This can be
exacerbated when a mask is introduced which decreases contrast in the
highlightss. Also, sometimes a sense of "sparkle" is lost when specular
highlights are increased in density by a contrast reduction mask. One answer
to either of these problems is to make a "highlight protection mask".
The highlight protection mask is made using Kodalith film. It's made sharp.
I.e. Emulsion to emulsion with the original in the contact printer. It's
exposed so that only the brightest highlights in the original show any density
in the highlight protection mask. Sometimes ferricyanide bleach is used
to remove unwanted density from it.
This mask is then laid
reduction mask. I.e.
"increases density" in
the contrast reduction
on top of the original when exposing the contrast
it goes between the original and the light source. It
the highlights so that they result in less density in
mask and print brighter in the final print.
I know one person (Charley Cramer) who has gone so far as to make a prehighlight-protection mask which was used when exposing the highlight
protection mask. The effect was to darken a small area in a highlight in the
final print. I haven't gotten quite this far into it yet.
An alternative is to use Kodak LPD4 positive litho film to make a "highlight
bump mask". This mask is exposed such that it's all black except for little
clear "holes" where the brightest highlights are. This film can show
significant chemical fog so it may be helpful to lightly bleach the
entire mask in dilute ferricyanide to clear the highlight areas.
After exposing the print with the contrast reduction mask, the negative carrier
is removed from the negative stage and the highlight bump mask is laid on top
of the original and an additional burn or "bump" exposure is made to brighten
the highlights. Obviously this type of technique can only be used if one
has a full pin registration setup. (You'll have to pry mine from my cold,
dead fingers - to take a page from the NRA. :-)
Once the registration equipment is available and some experience has been
gained there are lots of other possibilities. Contrast increasing masks.
Area masks - evenly toned masks which "dodge" an entire area of the print.
Kodalith area masks which are all black or all clear and allow printing
different parts of the print completely separately from the others. Lots
of new worlds to explore!
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================================================================================
Note 20.04
-< 3D FAQ or Frequently Asked Questions about stereo >-------------------------------------------------------------------------------Question:
I was wondering if there's a FAQ list that would cover some of the basics of
3d photography...... What kind of equipment is most frequently used for 3d
photography? I've heard a lot about beam splitters and Realists and stuff,
but I don't know where to buy them; none of the camera stores around here have
any 3d equipment.
Answer:
There IS an ftp site and it has a couple of files which may interest you.
One is the FAQ list and the other is the 3D products and services list.
To get there:
% ftp csg.lbl.gov
account <default>: anonymous
.., send ident as password... <put username here, won't echo>
<at this point you are logged in>
cd pub/listserv/photo-3d
<to get to our directory>
dir
<this shows list of what's there>
binary
<need this to transfer binary file>
get <filename> will transfer file to your home directory..
quit
At the present time the 3d directory looks like so:
2002
45512
83542
32467
203292
3537
2694
501655
201485
184006
184207
12041
423407
2324
19890
20205
6040
Jun
Mar
Aug
Aug
Mar
Jun
Jun
Mar
Mar
Jun
Jun
Mar
Mar
Mar
Mar
Mar
Mar
29
29
17
17
11
18
28
18
25
29
17
9
17
5
5
5
9
1.index
3d-faq.ps.Z
3d.prod.serv
3d.prod.serv.Z
ES.CTD.ACHR.PS.Z
ISU
NSA
archive_1.Z
dpthfld.ps.Z
ortho.mag.ps.Z
ortho.sep.ps.Z
photometry
raytrace.ps.Z
tc.expl
tc1.25.ps.Z
tc1.6.ps.Z
wratten.filters
"1.index" gives a description of the other files, as you might suspect.
================================================================================
file:///C|/faq.html (99 of 555) [7/19/2002 3:46:25 AM]
Note 20.05
-< Making Color out of B&W! >-------------------------------------------------------------------------------HOW TO MAKE HIGH CONTRAST BLUE, CYAN OR MAGENTA COLOR IMAGES
STARTING WITH A HIGH CONTRAST B&W ORIGINAL
by Dr. Lothar Engelmann
1)
Use a high contrast black & white film (e.g. lith film, microfilm or
Tech Pan) and develop in C-41 or E-6 color developer to which you
have added a color coupler solution. You would have to experiment to
establish the right amount (I would start with 10ml of the coupler
solution given below for 500ml of color developer). After development
you have to bleach, wash, fix and wash again before drying. This method
would give you a negative.
2)
Use a black & white high contrast image and change it to a color image.
Your image has to be well fixed and washed. This method involves the
following steps, which are all done in light:
a)
b)
c)
d)
e)
f)
g)
h)
i)
Bleach your image in C-41 bleach, E-6 bleach, or the bleach
formula given below, until the silver image is fully converted
to a silver-bromide (yellowish white).
Wash thoroughly and make sure your film is well exposed to the
light to form a latent image in the silver-bromide formed in
the bleach step.
Develop in C-41 or E-6 color developer to which you have added
coupler solution (I would use about 10ml per 500ml developer).
This may take 3 to 5 minutes. Since development goes to
completion there is no danger of overdevelopment. In this step
the silver bromide is developed to silver while the color
developing agent is oxidized. The oxidized color developing
agent reacts with the color coupler to form a dye.
Short stop for a few seconds. (see formulation below)
Wash for about 30 seconds.
Bleach again to convert the silver back to silver bromide.
The dye is not affected.
Wash until all bleach is removed.
Fix in any common film fixer for the time recommended for your
film.
Wash and dry. You are left with a monochromatic color image
which has replaced your original silver image.
Either of the two methods will work. The second converts the silver
image into a dye image. If you start with a negative you will get a
negative, if you start with a positive you will end up also with a
positive. If the cyan forming coupler does not give you the right blue
image, you could add a combination of cyan and magenta coupler solution
in a ratio of 3 to 2 to your color developer, rather than the cyan
coupler alone. You could also stop the process after the color
development and use the combination silver-dye image directly. In that
case you would simply have to wash after the development step.
PAGE 2
file:///C|/faq.html (100 of 555) [7/19/2002 3:46:25 AM]
FORMULATIONS:
Caution: All the chemicals used in the suggested processes may be toxic and/or
staining.
Bleach:
Potassium Ferricyanide
Potassium bromide
Water
30.0g
20.0g
1000.0ml
Short Stop:
Sodium Bisulfite
Water
10.0g
1000.0ml
Cyan Coupler Solution:
2,4-Dichloro-1-naphthol (EK #3704)
Acetone
750.0mg
100.0ml
Magenta Coupler Solution:
p-Nitrophenylacetonitrile (EK #3495)
Acetone
125.0mg
100.0ml
================================================================================
Note 20.06
-< Variable Contrast Filter Settings and Color Heads >-------------------------------------------------------------------------------dichroic filter settings for illford multigrade papers
calibrated filter settings for Ilford Multigrade MG-III Rapid
paper using a color head filtration system.
Grade
Filtration
-----------------0
80Y
1/2
55Y
1
30Y
1 1/2
15Y
2
0
2 1/2
25M
3
40M
3 1/2
65M
4
100M
4 1/2
150M
5
200M
If you need maximum contrast, dial
cyan, so you get nothing but blue;
contrast, use full yellow and full
green. This will give you about a
of the above scale, at the cost of
in full magenta and full
if you want minimum
cyan for nothing but
grade above/below the ends
long exposure times.
================================================================================
Note 20.07
-< Tech Pan Exposure/Processing Info >file:///C|/faq.html (101 of 555) [7/19/2002 3:46:25 AM]
-------------------------------------------------------------------------------Here is the data from Kodak data sheets: Exposure: the speed of this film
depends on the application, the type and degree of developement, and level of
contrast required. Therefore, no single speed value applies for all situations.
While you can use all the speed values given below as ISO (ASA/DIN) meter
settings, they are exposure indexes(EI), Not IS0 (ASA/DIN) speeds. The table
below is for scientific, technical, photomicrography, and electron-micrography
applications, use the table as a guide to obtain the required contrast. This
assumes you start with a subject of average contrast.
high contrast
-2.50
2.25-2.50
1.20-2.10
1.00-2.10
0.80-0.95
low contrast
0.50-0.70
Kodak DEV.
Dektol
D-19
HC-110(Dil B)
D-76
HC-110(Dil F)
DEV time
3 min
2-8 min
4-12min
6-12min
6-12min
Technidol Liquid 5-11min
Exposure index
200
100-200
100-250
50-125
32-64
16-25
For pictorial applications, use an exposure index of 25 and process the film
in Kodak TEchnidol Liquid Developer. To prepare a working solution empty the
contents of one bottle of dev. concentrate in a suitable 1-qt. container. Then
add water at 68-77F degrees(20-25C) to make one quart of dev. solution. This
dilution of developer(for 4x5 sheets) is one-half the working strength used
for roll film. Presoak film for 2-1/2 min in water of 68 degrees. Dev. for
8min. BE SURE the dev. is at 68 degrees. Rinse in Kodak stop bath SB-1a, SB-5
for 15 to 30 sec. or running water for 30 sec. Fix for 2 to 4 min. and wash
for 5 to 15min save water by using kodak hypo clearing agent.
PICTORIAL PHOTOGRAPHY: Because the sensitivity of this film extends further
into the red region than conventional panchromatic films, the recording of red
objects will be slighty lighter than normal in print. In some cases this
characteristic may be desirable. For example, it helps reduce the effect of
some types of skin blemishes and in many cases produces a luminous quality to
skin tones which many observers consider quite pleasing.
FILTRATION is usuall not required in either portrait or scenic pictorial
photography. However, in some cases filtration may be required. In particular,
Caucasian flesh tones in full sun may look too light and possibly pasty. This
effect is less evident in shade portraits outdoors because there is less red
light present. In some cases, a Kodak Wratten filter #38 or Kodak CC filter
CC40C used without a filter factor, may be sufficient to lessen the excess red
sensitivity. Because of variations in circumstances and tastes, experimentation
is in order. Kodak Technidol LC Developer is available in a 3-pack each pouch
holds enough powder to make 1 US pint. This is sufficent to process 2 35mm 36exp
rolls.
EXPOSURE INDEX: 25 for trial exposures. This is based upon the formula EI=.81E
where E is the 1/25 second exposure in lux seconds required for a density of
.1 above Base plus Fog.
PS: You can contact Kodak at 800-242-2424 and ask for publication P-255 or
write them at Customer Technical Services, Eastman Kodak 343 State Street,
Rochester, New York 14650.
file:///C|/faq.html (102 of 555) [7/19/2002 3:46:25 AM]
From: [email protected] (Nick Myers)
Subject: Re: Using Techinal Pan
Organization: University of Tennessee
================================================================================
Note 20.08
-< Sound Synchronizers - Cheap and Simple >-------------------------------------------------------------------------------For high speed photography the problem generally centers around triggering the
camera or flash at the right time and how to do it. For this photographers
rely on various synchronizers. Below are two schemes designed to trip an
electronic flash by detecting sound waves. The very simplest sound sensitive
synchronizer one could make might be the one described below:
You obviously have to figure out how to connect the
flash sync cord to this device which looks like this:
To Flash
.....................................
_______:
-_-----------------------_- |: <- thin strip of aluminum foil
|:
taped to tightly stretched
|:
rubber membrane with 2-sided
|:
tape.
|:
TIN COFFEE CAN
|:--. <- tip of wire _almost_
both ends removed
|: |
touching aluminum foil
|
|
rubber membrane from balloon or such -> |
|
covering one end of coffee can
|
|
_-_______________________-_ |
|
-----| <- wire insulated to here
=========================================
To Flash
point open and of can towards source of loud sound ... if you set everything up
VERY carefully flash will go off when aluminum foil comes in contact with tip
of wire located VERY near, but NOT touching, it.
Here is another simple sound sync which is much more sensitive but is also a
bit more expensive. It consists of one electronic part plus a common, hopefully
already available, casette tape recorder. The idea is to simply couple a SCR to
the EARPHONE jack of the casette tape recorder and hook up the flash sync
contacts to the SCR.
First, get a SCR that can handle 250 or 400 volts between Anode and Cathode such as
C106D. Radio Shack has them or similar, I believe.
Use a plug that fits into the earphone jack and connect the CATHODE and GATE
leads to the two, normally open, connections on the plug. Then, connect the
CATHODE and ANODE leads on the SCR to the flash sync contacts. Make sure plug
is now UNPLUGGED from the EARPHONE jack.
Now, put a tape in Tape Recorder and activate the Tape Recorder so it is now in
file:///C|/faq.html (103 of 555) [7/19/2002 3:46:25 AM]
RECORD mode. Make sure it is very quiet in the room. Now plug the jack into the
EARPHONE jack. The flash should fire. It should also fire each time you make a
tiny sound assuming the flash has recycled.
If it does NOT do fire the flash it is possible the connections between the
flash and the SCR are hooked up "backwards". Try moving sync cord connections
to opposite SCR leads. Now the synchronizer may or may not work.!!!!
The IDEA here is that the VOLTS generated by the recorder when recording and
which would drive the earphone can be used to turn on a SCR which in turn
triggers the flash upon sensing a sound. CHEAP, quick, dirty and unfortunately
somewhat unreliable. But so what did you want for nothing?
================================================================================
Note 20.09
-< Convenient Pulfrich Effect 3D Viewing >-------------------------------------------------------------------------------The Pulfrich 3D effect and Switchable Glasses
The Pulfrich effect allows you to get a 3D effect from normal television
sometimes, by wearing glasses with one dark lens and one clear lens (such as
sunglasses with one of the lenses missing). If the dark lens is the left one,
then anything on the screen that's moving right-to-left in relation to the
background scenery will appear to be in front of it. Likewise, if the dark lens
is the right one, then objects moving left-to-right will appear closer than the
background. Ice skating is a good type of program to watch in order to be
guaranteed of some good side-to-side motion shots, and Mike Watters has pointed
out that the introduction to the "Star Trek: The Next Generation" has a good
shot in which the Enterprise moves left-to-right in front of a background of
stars.
But how do you switch the dark/clear side of your glasses in a hurry, when a
motion-shot comes on the screen that's in the wrong orientation for your
glasses? After months of detailed and painstaking research, I've discovered a
good answer. The company whose address appears below sells something called
"flip-up glasses". They're cheap plastic sunglasses whose lenses flip up
_individually_. They're certainly not intended for use as Pulfrich glasses,
but I have a pair, and they work great for that purpose. You can instantly
flip one dark lens up and the other one down when necessary, without even
taking the glasses off. They cost $1.95 per pair (plus postage).
The rest of their free mail-order catalog is quite wonderful! They sell cheap
novelties and other weird things that apparently didn't sell very well in
stores. For instance, there's an inflatable buffalo, a plastic monkey that
blows smoke rings, and a glow-in-the-dark water gun shaped like a squid. Other
3D-related items include various cheapo holograms of eyeballs (some mounted in
glasses), and a vinyl card (presumably lenticular) which shows a portrait of
Jesus when you look at it one way and a picture of the Shroud of Turin when you
look at it another way. Truly a smorgasbord of essential items. Here's the
address...
Archie McPhee
Box 30852
Seattle, WA 98103
U.S.A.
order desk and info line: (206) 782-2344
file:///C|/faq.html (104 of 555) [7/19/2002 3:46:25 AM]
From: Tim Klein <[email protected]>
================================================================================
Note 20.10
-< What is EV (Exposure Value)? >------------------------------------------------------------------------------->Can someone tell me what the relationship is between LUX and EV and ASA?
>For example can I determine LUX from F number, Speed and ASA and vice versa?
Well, according to ANSI PH 3.49-1971 (R1976) [American National Standard for
General Purpose Photographic Exposure Meters (Photoelectric Type), thing's are
related thusly:
2^EV = BS/K
where
EV = exposure value.
B = Field luminance.
S = ISO/ANSI film speed
K = exposure constant (reflected light); the luminance units
which B must be expressed in must be identified for any
given K value to be meaningful since B and K change
proportionally.
If B is in candelas/meter^2
footlamberts
candelas/ft^2
K=12.5
K= 3.65
K= 1.30
And:
2^EV = A^2/T
where
A = f-number of aperture
T = shutter time in seconds
In other words, EV = log2(A^2/T) = log2(B*S/K).
Note that EV is a measure of *EXPOSURE*, not of illumination. EV0 is *by
definition* an exposure of 1 sec at f/1, or any equivalent *exposure* (2
sec@f/1.4, 4 sec@f/2.0, etc, etc). When people refer to a given brightness
level as EV1, they usually mean "EV1 for a film with an ISO speed of 100".
>So does an EV number stand for an absolute amount of light?.
Again, EV is a measure of *exposure*. It is, by definition, log2(A^2/T), where
A is the aperture (f/ number) and T is the exposure time in seconds. That's why
it's an EXPOSURE Value and not a LUMINANCE Value.
The usage of EV by itself to express a light level seems to have originated
with advertising copywriters who were too damned lazy to write "EV at ISO
100", which is typically what they mean.
>Since you normally measure EV or LUX, and then, using ISO or ASA compute the
>F number and shutter speed, can you do the conversion in the other direction
>using any light meter and find the amount of light falling on a scene?.
Actually, you really normally measure light level, and then, using ISO or ASA
file:///C|/faq.html (105 of 555) [7/19/2002 3:46:25 AM]
compute the EV (which is a neat way of referring to all possible combinations
of aperture and shutter speed which produce the exposure you want).
Contributed by Steve Gombosi, [email protected]
================================================================================
Note 20.11
-< Info on Film and Video Resources on the Internet >-------------------------------------------------------------------------------Guide to Film and Video Resources on the Internet
This guide includes information on many resources such as listservs and
USENET news groups on topics related to film and video, as well as film
review databases, filmographies, etc.
Our intention in compiling this guide was to locate as many resources
as possible in the subject area of film and video which are available
on the Internet. While it is not a definitive source, it is a good
place to start if you are looking for information about film and video.
We intend to maintain this guide as an ongoing project and would
encourage any comments you have.
The guide is now available but since it is 72K we chose not to post it
on the listservs and news groups. While we will be happy to send a copy
(absolutely free) through e-mail to anyone interested, we wanted to
warn everyone that it is a very big file and that people are better off
accessing it in the following ways:
anonymous FTP:
host:
path:
una.hh.lib.umich.edu
/inetdirsstacks
Gopher:
via U. Minnesota list of gophers
menu: North America/USA/Michigan
Gopher .link file:
Name=Clearinghouse of Subject-Oriented Internet Resource Guides (UMich)
Type=1
Port=70
Path=1/inetdirs
Host=una.hh.lib.umich.edu
Uniform Resource Locators (URLs) for WWW/Mosaic:
http://http2.sils.umich.edu/~lou/chhome.html or
gopher://una.hh.lib.umich.edu/11/inetdirs
_Film and Video Resources on the Internet_ was created during the fall
semester, 1993 at the School of Information and Library Studies. It is
the final project for the course ILS 606 Internet: Resource Discovery
and Organization. This guide and numerous other subject -oriented
Internet resource guides are available from the Clearinghouse for
Subject-Oriented Internet Resource Guides using the methods described
above.
file:///C|/faq.html (106 of 555) [7/19/2002 3:46:25 AM]
Once again, thank you to everyone who provided information and
assistance with our guide. If you have any questions about the guide,
please feel free to send us a message.
Note 21.01
-< A DOF program written in C FYI >-------------------------------------------------------------------------------From: [email protected] (Bill J. Thomas)
Subject: depth of field c code
Organization: cisco Systems
the following is a Depth of Field program written in C
*******************************************************************
%dfield
enter
enter
enter
Enter
focal length in mm's 135
Y for 35 mm N for roll or sheet film Y/N? n
focal length in mm's for depth of field f ratio scale 135
plot scale increment e.g., 0.4 now 0.4
Feet
f scale
f3.5
0.130
f4
0.148
f5.6
0.207
Focus in Feet
4.921 Scale is
Focus in Feet
5.150 Scale is
Focus in Feet
5.401 Scale is
Focus in Feet
5.678 Scale is
Focus in Feet
5.985 Scale is
Focus in Feet
6.327 Scale is
Focus in Feet
6.711 Scale is
Focus in Feet
7.144 Scale is
Focus in Feet
7.636 Scale is
Focus in Feet
8.202 Scale is
Focus in Feet
8.858 Scale is
Focus in Feet
9.629 Scale is
Focus in Feet 10.546 Scale is
Focus in Feet 11.656 Scale is
Focus in Feet 13.027 Scale is
Focus in Feet 14.764 Scale is
Focus in Feet 17.035 Scale is
Focus in Feet 20.132 Scale is
Focus in Feet 24.606 Scale is
Focus in Feet 31.637 Scale is
Focus in Feet 44.291 Scale is
Focus in Feet 73.819 Scale is
Focus in Feet 221.457 Scale is
Compute Depth of Field Table Y/N?
End computations ? (Y/N) n
enter focal length in mm's 90
file:///C|/faq.html (107 of 555) [7/19/2002 3:46:25 AM]
f8
0.296
9.000
8.600
8.200
7.800
7.400
7.000
6.600
6.200
5.800
5.400
5.000
4.600
4.200
3.800
3.400
3.000
2.600
2.200
1.800
1.400
1.000
0.600
0.200
n
f11
0.407
f16
0.593
f22
0.815
f32
1.185
enter Y for 35 mm N for roll or sheet film Y/N? n
enter focal length in mm's for depth of field f ratio scale 135
Feet
f scale
f3.5
0.292
f4
0.333
f5.6
0.467
f8
0.667
f11
0.917
f16
1.333
f22
1.833
f32
2.667
=====================plot depth of field slide rule=============
Lay out the "DISTANCE SCALE" using the numbers from the Focus in Feet
display.
Draw a vertical line (DISTANCE SCALE).
At the top print the symbol for infinity.
Next at 0.200 inches (2/10'ths of an inch) print 221.457 feet.
Continue with the rest.
At the bottom at 9.000 inches from the top print 4.921 feet.
Lay out the 135 mm lens "DEPTH of FIELD SCALE" using the numbers
from the 135 mm "f scale" display.
Draw a horizontal line with an arrow at the right end (FOCUS ARROW).
Draw a vertical line through the horizontal "FOCUS ARROW LINE".
On the vertical line print f11 "0.407" inches above and below
the "FOCUS ARROW LINE".
Repeat the above for the rest of the numbers in the "f scale"
display.
USAGE: Align the vertical line of the "DEPTH of FIELD SCALE" with the
"DISTANCE SCALE". Set the "FOCUS ARROW" at the focus distance
on the "DISTANCE SCALE" (say 17 feet). Now for a given lens
opening (say f11) read off the distance both before and after
the focus distance (14.7ft & 20.2ft). Everything between these
distances will be in focus (based on the "circle of confusion"
built into the code based on your answer to "enter Y for 35 mm
N for roll or sheet film Y/N?").
Lay out the 90 mm lens "DEPTH of FIELD SCALE" using the numbers
from the 90 mm's "f scale" display as was done for the 135 mm lens.
By running a series of different lens lengths less than in this case 135 mm,
you can construct a "DEPTH of FIELD SCALE" like the ones found on many
zoom lenses.
*******************************************************************/
#include <stdio.h>
main(){
float F, H, u, c, dn, df, Hu, F_scale, H_scale;
char type_c;
#define MAX_u 1000
float u_range[MAX_u];
float v_delta;
float v_ratio;
#define max_f 8
file:///C|/faq.html (108 of 555) [7/19/2002 3:46:25 AM]
short max_u;
#define TRUE 1
float temp[max_f];
short i, j;
/*float f_range[] = {3.5, 4.0, 5.6, 8.0, 11.0, 16.0, 22.0, 32.0};*/
float f_range[max_f];
f_range[0]
f_range[1]
f_range[2]
f_range[3]
f_range[4]
f_range[5]
f_range[6]
f_range[7]
=
=
=
=
=
=
=
=
3.5;
4.0;
5.6;
8.0;
11.0;
16.0;
22.0;
32.0;
printf("\n Lense Depth of Field Calculations");
printf("\n
Copyright (C) 1992. ");
printf("\n
All rights reserved ");
printf("\n
Bill Thomas ");
printf("\n
43559 Southerland Way ");
printf("\n
Fremont, CA 94539 \n");
while(TRUE){
printf("\n enter focal length in mm's ");
scanf("%f", &F);
if(F < 0.0) exit(0);
printf(" enter Y for 35 mm N for roll or sheet film Y/N? ");
scanf("%s", &type_c);
printf(" enter focal length in mm's for depth of field f ratio scale ");
scanf("%f", &F_scale);
if(F > F_scale) {
printf("\n f ration length can't be less than focal length \n");
continue;
}
F *= 0.03937;
F_scale *= 0.03937;
if(type_c == 'Y' || type_c == 'y')
c = 0.001; /*for 35 mm*/
else {
if(type_c != 'N' && type_c != 'n'){
printf("\n ***ERROR*** enter Y or N!!! ");
continue;
}
c = 0.0019685; /*roll or sheet film*/
}
H_scale = F_scale/F;
/*compute feet depth scale so as to be plotted at v_delta increments */
v_delta = 0.4;
if(F_scale == F){
printf(" Enter plot scale increment e.g., 0.4 now ");
scanf("%f", &v_delta);
}
v_ratio = 9.0;
file:///C|/faq.html (109 of 555) [7/19/2002 3:46:25 AM]
i = -1;
while(i++ < MAX_u && v_ratio > 0.00001){
u_range[i] = F_scale/(v_ratio*12)*100;
v_ratio -= v_delta;
}
max_u = i;
printf("\n\n
Feet
f3.5
f4
f5.6
f8
f11
f16
f22
f32");
printf("\nf scale ");
for(j = 0; j < max_f; j++){
H = F*F/(f_range[j]*c);
/*see v_ratio computation below*/
v_ratio = F/H*100*H_scale;
printf(" %8.3f",v_ratio);
}
if(F_scale == F){
printf("\n\n");
for(i = 0; i < max_u; i++){
u = u_range[i];
/*m = F/(u*12); */
/*v = F*(1 + m);*/ /*lens formula*/
/*v_ratio = (v/F - 1 )*10; */
v_ratio = F/(u*12)*100;
printf("\n Focus in Feet %7.3f Scale is %8.3f ", u, v_ratio);
}
}
printf("\n Compute Depth of Field Table Y/N? ");
scanf("%s", &type_c);
if(type_c == 'N' || type_c == 'n')goto EndTableComp;
printf("\f \n
f3.5
f4
f5.6
f22
f32");
printf("\n
FOCUS");
printf("\nInfinity");
for(j = 0; j < max_f; j++){
H = F*F/(f_range[j]*c);
printf(" %8.1f", H/12);
}
printf("\n
");
for(j = 0; j < max_f; j++)
printf(" infinity");
for(i = 0; i < max_u; i++){
u = u_range[i];
printf("\n %7.1f", u);
u *= 12;
for(j = 0; j < max_f; j++){
H = F*F/(f_range[j]*c);
Hu = H*u;
dn = Hu/(H+u);
temp[j] = df = Hu/(H-u);
if(dn < 0.0)
printf(" infinity");
else
printf(" %8.1f", dn/12.0);
file:///C|/faq.html (110 of 555) [7/19/2002 3:46:25 AM]
f8
f11
f16
}/*end of for(j */
printf("\n
");
for(j = 0; j < max_f; j++){
if(temp[j] < 0.0)
printf(" infinity");
else
printf(" %8.1f", temp[j]/12.0);
}/*end of for(j */
}/*end of for(i */
EndTableComp:
printf("\n\n End computations ? (Y/N) ");
scanf("%s", &type_c);
if(type_c == 'Y' || type_c == 'y')
exit(0);
}/*end while(1) */
}
================================================================================
Note 21.02
-< Polaroid batteries and accessories >-------------------------------------------------------------------------------Are you looking for batteries to power up your old Polaroid camera? Do you need
accessories? Then the FREE catalog of the following outfit may interest you.
Graphic Center
P.O. Box 818
Ventura, CA 93002
1-800-336-6096
They carry batteries and various accessories. They also convert Polaroid 110A/B
to use standard pack film. They also carry refurbished plastic and metal pack
film cameras, electronic flashes designed to fit 100-450 seies cameras, EE-100,
Reporter, and others. Interesting accessories include PC-flash adapter cords,
cold clips, filters, cable releases, closeup kits, portrait kits, and filters.
As for batteries, the No. 532, are $7 each., the 4v No.531 batteries are $7.75.
================================================================================
Note 21.03
-< Infrared Ektachrome Processing in E-6 chemicals >-------------------------------------------------------------------------------Ektachrome Infrared processing in E-6
The simplest information on E-6 processing of film intended for E-4 was in
Darkroom & Creative Camera Techniques magazine, Nov/Dec 1989, page 2. They
had previously tried processing E-4 film in E-6 chemistry, but at 70F. This
took a lot of time and the results were questionable. They then recommended
using a prehardener and neutralizer before the first developer (such as is
used in E-4), and then doing the E-6 process as usual at 85F. There hasn't
been any follow-up comment about this since last year in the magazine. The
formulas below should work adequately.
E-4 Prehardener
Water
Sodium Sulfate
Formaldehyde 38%
file:///C|/faq.html (111 of 555) [7/19/2002 3:46:25 AM]
800 mL
140 g
30 mL
Potassium Bromide
Water to make
E-4 Neutralizer
Water
Hydroxylamine Sulfate
Potassium Bromide
Sodium Acetate
Glacial Acetic Acid
Sodium Sulfate
Water to make
16 g
1 L
800 mL
18 g
20 g
7 g
7 mL
50 g
1 L
These two solutions may be reused.
Most of the chemicals should be available from: Lauder Photographic, 2650B
Mercantile Dr. Rancho Cordova, CA 95670, 916-638-1225,Zone V, Stage Rd, S.
Strafford VT 05070, 802-765-4508, Tri-Ess Sciences, 1020 W. Chestnut St.,
Burbank, CA 91506, 213-245-7685. Rapid Fixer should be available from your
photo dealer. Formaldehyde is available at most any drug store.
Schedule at 85F:
Prehardener
3 min
Neutralizer
1 min
First Developer and remaining steps per standard E-6
directions for a processing temperature of 85F.
The E-6 kit recommended in the article was the Kodak E-6 Hobby Pak Kit.
Obviously, these aren't official E-4 formulas, but they should work OK. The
biggest problem with E-4 film is that the emulsion isn't prehardened, and it
gets too soft at normal E-6 temperature (100F). There possibly could be some
color shift, but I would guess if you are wanting to do Ektachrome Infrared
how would you know a color shift if you saw it??? :)
I hope that this information works for you.
Ron Speirs, Evans & Sutherland Computer Corp., Salt Lake City, UT
================================================================================
Note 21.04
-< New f# when using bellows extension >-------------------------------------------------------------------------------How to adjust for bellows extension factor/stops
It's actually pretty easy to do the arithmetic for this computation in your
head. The effective f-stop is simply the marked f-stop times the ratio of
lens-to-film distance (bellows extension) to focal length.
For example, say I have my handy Schneider 210 mounted up, and I'm taking a
picture of something at a magnification of 1:1, and I need to set the lens to
f/22 to get everything adequately sharp. The lens-film distance according to
the tape will be 420mm, focal length is 210mm, f-stop is 22. My effective
f-stop will be 22 x 420 / 210 = 44. Call it f/45 and dial that into the meter.
That's all there is to it.
This formula provides an additional benefit - you can calculate a magnification
file:///C|/faq.html (112 of 555) [7/19/2002 3:46:25 AM]
or distance for which you needn't bother getting out the tape measure.
If 1/6 stop is the largest error you find tolerable, that means that the
lens-film distance/focal length ratio must be 7/6 or less. Plugging that into
the formula for focal length (fl), lens-film distance (d_lf) and lens-object
distance (d_lo),
1/fl = 1/d_lf + 1/d_lo
1/fl = 1/(7/6*fl) + 1/d_lo
d_lo = 7*fl
which means if you are more than 7 focal lengths away from your subject, your
underexposure due to ignoring bellows extension will be less than 1/6 stop. If
you're willing to go to 1/3 stop error, 4 focal lengths is the threshold. In
general, if you are willing to set your error threshold at "err" f-stops, the
nearest you can get to your subject without compensating for bellows extension
is (1+err)/err focal lengths. In the case of my 210mm (aka 8 1/4") lens, if
I'm making life difficult for myself by using color transparency film, and I
think I can meter things accurately enough that 1/3 stop accuracy is crucial
(don't I wish!) I can see that if I'm closer than about 3 feet I need to get
out that tape measure.
Fortunately, since I mostly shoot b&w, and more often than not I'm doing
landscapes, I can see from the formula that I don't have to worry much about
the fact that I lost my tape measure a few months ago :-)
Bill
From: [email protected] (Bill Palmer)
Organization: Stanford University CSLI
================================================================================
Note 21.05
-< Data on Wratten Filters by the Numbers >-------------------------------------------------------------------------------This is a listing of Wratten Filters by number, their color and
applications. It was compiled from the CRC Handbook where more
filters and additional charactristics are also listed.
Wratten
filter
number color
use
colorless
UV(0)
none
absorbs UV
0
clear
thickness compensation
1
absorbs UV < 360nm
1A
pale pnk skylight filter
1B
lt. pink (skylight) cuts blue cast in shade and distance, absorbs UV
yellows
2A
pale yel
2B
pl yel
2E
pl yel
UV 405 nm
absorbs UV 390 nm
absorbs UV
file:///C|/faq.html (113 of 555) [7/19/2002 3:46:25 AM]
3
lt yel
4 lt yel CCC - corrects outdoor scenes for panchromatic film
6
lt yel (aka K1) partial correction for outdoors
8
yel
(aka K2) full correction outdoors for Type B panchromatic film
9 dp yel
11
yl-grn (aka X1) corrects tungsten light for Type B film
12
dp yel minus blue - haze cutting for aerial photography
13
yel-grn (aka X2) corrects tungsten light for Type C panchromatic film
15
dp yel (aka G) contrast control in aerial IR photography
16
yel-org blue absorbtion
18A
transmits UV and IR only
oranges and reds
21
org
blue and blue-green absorbtion
22
dp org yellow-orange (mercury yellow) increase contrast in blue
preparations for microscopy
23A lt red contrast effects
24
red
for two-color photography
25
red
(aka A) for tri-color separation, high contrast effect,
aerial IR haze
two-color general viewing
26
red
stereo red
29
dp red high contrast, tungsten projection of tri-color, red sep. in
fluor. process
magentas and violets
30
green absorbtion
31
green absorbtion
32
magen
minus green
33
strong green absorbtion
34A
violet blue separation in fluorescence process
35
contrast in microscopy
36
dk violet
blues and blue-greens
38
red absorbtion
38A
Blue
red absorbtion, increasing contrast in visual microscopy
39
contrast control in printing motion pictures
40 green
two-color photography
44 lt blu-grn minus red, two-color general viewing
44A
lt blu-grn minus red
45
contrast in microscopy
46
blue projection
47
blue
direct color separation, tungsten tri-color projection
47A
lt blue
47B
dp blu tri-color separation form transparencies
48
green and red absorbtion
48A
green and red absorbtion
49
dark blue
50
very dark blue - mercury violet
greens
52 lt grn
53
54
middle green
very dark green
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55
56
57
57A
58
59
59A
60
61
64
65
66
67A
stereo green
very light green
green for two-color photography
lt grn
grn
tri-color green for separations, contrast in photog & microscopy
green for tri-color projection
very light green
green for tungsten two-color photography
dp grn grn tri-color sep, tungsten projection
red absorbtion
red absorbtion
contrast effects in microscopy & medical photography
red absorbtion
Two-color projection
narrow band
70
dk red IR photography
72B
dk or-yel
605 nm
73
dk yel-grn
575
74
dk grn mercury green
539
75
dk blu-grn
488
76
dk vio (compound filter)
676 nm
nm
nm
nm
449 nm
Hg line filters
77
transmits 546 nm mercury line. glass plus gelatin
580 nm
77A
transmits 546 nm mercury line. glass plus gelatin
582 nm
photometrics
78
bluish photometric filter (visual)
78AA bluish photometric filter (visual)
78A bluish photometric filter (visual)
78B bluish photometric filter (visual)
78C bluish photometric filter (visual)
86
amber
photometric filter (visual)
86A amber
photometric filter (visual)
86B amber
photometric filter (visual)
86C amber
photometric filter (visual)
light balancing
80A blue color correction for daylight film (5500) under 3200K (studio) lamps
80B blue color correction for daylight film (5500) under 3400K (photo) lamps
80C blue color cor. for daylight film (5500) under 3800K (clear flash) lamps
81 amber warming -100K
81A amber color correction for Type B tungsten film under 3400K (photo) lamps
warming -200K
81B amber to remove blue cast in shaded daylight
warming -300K
81C amber to remove blue cast in cloudy/rainy weather; Kodachrome Type A with
flash; warming -400K
81D amber Kodachrome Type A with flash; warming -500K
81EF amber Ektachrome Type B with flash; warming -650K
82
blue cooling +100K
82A blue color correction for Type A tungsten film under 3200K (studio) lamps
cooling +200K
82B blue color correction for Type B tungsten film under 2900K (100w incand.)
cooling +300K
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82C
blue to remove reddish cast in early morning or late afternoon
cooling +400K
83 amber 16mm commercial Kodachrome in daylight
85 orange color correction for Type A tungsten film in daylight (5500K->3400K)
85B orange color correction for Type B tungsten film in daylight (5500K->3200K)
85C amber converts 5500K (daylight) to 3800K lighting
miscellaneous
79
photographic sensitometry
87
for infrared photography; IR
770nm ->
87C
absorbs visual, transmits IR
830nm ->
88A
for infrared photography; IR
740nm ->
89B
for infrared photography; IR
700nm ->
90
monochrome viewing (narrow-band for viewing scene brightness);
about 570->590 nm; 10% luminous transmittance
96 neutral filter for controlling luminance; 9% luminous transmittance
97
dichroic absorption
102 correction filter for Barrier-layer cell
106
correction filter for S-4 type photocell
FL-day purple converts daylight fluorescent light for daylight film
FL-W
purple
converts white fluorescent light for daylight film
K2
yellow
improves contrast in B&W; absorbs UV and part of violet
G
orange greatly improves contrast in B&W; absorbs UV and part
of blue-green
25A
red
strongest B&W contrast; absorbs UV and part of yellow;
"night filter"
also used as a color separation filter with #47 blue and
#58 green
X0
yel-grn natural rendition of skin and lips of female models
B&W?
X1
green
Absorbs more red than X0, good for green trees
B&W?
Data on a very few narrower band filters:
Filter no.
low l
high l
domin. l
Color separation filters:
47 blu
400
475
58 grn
490
600
25A red
590
700
Narrow band filters:
76
400
470
75 460
530
488
74
510
570
539
73
560
600
575
72B 590
640
605
70
660
700
676
464
540
615
lum. transm.
2.8
23.7
14
449
.046
1.3
4.0
1.3
.74
0.31
This file was found in the photo-3D FTP-able archives at csg.lbl.gov.
================================================================================
Note 21.06
-< CHEAP IR Filters - experimental quality >--------------------------------------------------------------------------------
file:///C|/faq.html (116 of 555) [7/19/2002 3:46:25 AM]
In case you did not know and might benefit from this information I had
some filters often used for Infrared photography, along with some unexposed
but developed Ektachrome sheet film, characterized with a spectrophotometer.
The films were obviously visually quite opaque. Especially if you stacked two
of these. It turns out that the dyes that make up the color layers in this
film (and I suspect all color films) are visually opaque but IR TRANSPARENT!
This means they can be used as cheap makeshift IR filters, especially to cover
a flash source to make unobtrusive flash photos by IR illumination. This info
is not totally new as I had already seen such curves at RMIT in Melbourne,
Australia, where I spent my summer vacation a couple of years ago. I also used
one and two layers of Ektachrome film as a filter in front of my camera's lens
and the images were not totally fuzzy and unusable. They had, in fact, a visual
quality all their own which you may (or may not) like if and when you
experiment in a similar fashion.
andy - andpph@ritvax
3.0|.........
..........
....... ------|
\__/
:\__/
\
; |
: Wratten #25 (red)
|
:
\
;
|
|
:
\ ;
|
; Wratten #87 (IR)
D
|
:
\ ;
|
E 2.0|
approximate
:
\ ;
|
\ 1 layer Ektachrome
N
| Density vs Wavelength :
\;
|
S
|
for
:
\
|
| 2 layers Ektachrome
I
| 2 Wratten Filters and :
;\
|
Y
| Ektachrome Sheet Film :
; \
|
1.0| unexposed & developed :
; \ |
|
:
; \ |
|
:
; \ |
|
:
; \ '- ________
|
'.............>
;-...........
-------------|------------|-------------|------------|------------|-----400
500
600
700
800
900
wavelength (nanometers)
...............................................................................
NOTE: ADDENDUM ABOUT PLACING FILTERS IN FRONT OF FLASH HEADS ->The RIT faq said that I could make an infrared flash from my Sb-24 flash
>by taping 2 strips of unexposed/developed E-6 film. supposedly, the two
>strips only allow IR to pass, blocking all visible light, so you can shoot
>in the dark. however, they didnt warn me that the flash could burn out because
>of the heat from the flash head. anyone know how i can overcome this problem.
>i am thinking of making a box and placing the strips further away, but the
>flash head gets really hot.
Anything that prevents energy from the flash to exit as freely as possible will
have a tendency to raise the temperature of the lighing fixture. Thus placing
filters, whether dense E6 material (cheap) or Kodak Wratten IR filter gels
(expensive), will cause the temperature within the head to rise. This is
especially true of the filter material itself and many photographers who tape
IR filters over their flashes for surreptitious IR photography find that their
filters become crinckled and are no longer suitable for use in front of a lens
after even a single close-up blast from a flash head.
The problem has to do with keeping energy IN. That is bound to raise the
temperature. A prudent move would be not to flash the tube too often and thus
file:///C|/faq.html (117 of 555) [7/19/2002 3:46:25 AM]
allowing the heat buildup associated with a single flash to dissipate before
firing the flash again. An alternative is to buy a dedicated IR flash which is
designed specifically for IR photography. Money seems to solve a lot of
problems.
;-)
andy, [email protected]
...............................................................................
Well, this may not be of help in your situation, but years ago when I was
experimenting with slippin' about in the dark taking flash pictures, I was
using the workhorse Vivitar 283. The 283, as you may recall, has a clip-on
plastic filter holder for Vivitar's line of accessory tele fresnels, WA
diffusers and colored filters. I bought a second one of those, and
light-tightly black-taped in the precisely correct Wratten gel (which I'd
special-ordered, anal technogeek that I was and I fear often still am). Worked
just fine.
So, if all you have is that silly Nikon flash :-), you might see if the Vivitar
piece will slip on it, or just make something similar from cardboard. A neck
to slip over the front of the flash-head, a part which widens like a
rectangular lens-shade, and a place for filters about 1-1.5 inches away from
the front of the flash. No smoke.
-Jeff Moore, [email protected]
...............................................................................
>I've heard of a couple of SB-24 flash front covers being melted/warped when
>a filter was inserted _behind_ the front panel. That flash must run really
>hot. ... don't tape it on, because the flash will overheat. when i did this,
>i heard a popping sound, and a burning rubber smell. i don't know which sb-24
>you have, but there is no space to insert something "behind the front panel"
>I tried the same thing on a vivitar 2600D (put the strip further away) and it
>still heated up. So this is not only the sb-24's problem.
When I used a wratten 87 gel on my Honeywell 810 [about GN160@EI100] I put the
accessory polycarbonate lens on first, and then the gel. This unit may have
better air circulation than an SB24 or similar unit, as it did not fry.
*However* after one roll, the gel was "embossed" with the waffled pattern of
the flash lens due to heat. Perhaps you should just ask your local pro lab to
proc a blank sheet of 4x5 E6 for you and then mount it at a distance from the
flash lens.
Regards,
David Rosen, dr8192@albNYvms
..............................................................................
The way I did is to buy a Vivitar 283 filter adapter. I found out that the hood
can be fit into the head of an SB24 if you just open (but cut a small line) the
adapter four corners a bit in its back. Now I get a filter adapter for sb24 and
I also can use the Vivitar's wide angle, zoom, and color filter for the sb24. I
use those filter a lot and never have any problem like melting the flash head.
The Vivitar 283 filter adapter leave a lot of space between the sb24 flash head
and the filter. Hope this help.
Larry, [email protected] (MA k.l.)
================================================================================
Note 21.07
-< UV and IR Technique Basics >file:///C|/faq.html (118 of 555) [7/19/2002 3:46:25 AM]
-------------------------------------------------------------------------------ULTRAVIOLET and INFRARED PHOTOGRAPHY SUMMARIZED
by Andrew Davidhazy
Imaging and Photographic Technology
Rochester Institute of Technology
A large part of the spectrum and its relationship to the world around us is
invisible because we are limited to seeing electromagnetic wavelengths which
extend only from those characteristic of violet-blues to those of the deep
reds. Photographic materials can extend our vision, especially when aided by
special light sources and various filters. The proper use of film, lights,
filters, exposure techniques and specific applications of the four basic
methods of photographing the invisible spectrum are discussed below.
The premise for photographing by REFLECTED ULTRAVIOLET or REFLECTED INFRARED
radiation is that we desire to "see" the interaction, by way of reflected
energy from our particular subject, of UV or IR rays as compared to the effect
on the same subject of visible light rays. The hope is that the subject may
appear differently by these rays than it does by "white" light or than it would
appear if seen through colored filters.
An analogy for the reason to apply these techniques is the lengths to which we
go to render a blue sky dark on a B&W print to contrast it against the white
clouds. This, of course, is accomplished by placing a yellow or red
(complementary colors to blue and cyan, the color of the sky) filter over the
camera lens. The filter does not allow the sky color wavelengths to pass on to
the film and thus the sky is rendered clear on the negative and dark on the
print. The point is that we can distinguish between two subjects of similar
tone, the sky and the clouds in this instance, but different color by filtering
out one of the colors with a filter of complementary color placed over the
camera lens. This principle applies also to the invisible areas of the spectrum
but we need films which can "see" in these areas in order for our own eyes to
see the differences if they exist.
Since UV and IR wavelengths are invisible to our eyes and thus can not be
assigned a "color" as such, B&W film is the most appropriate to use for both of
the above applications. Almost any B&W film can be used for reflected UV
photography although the slower emulsions seem to deliver somewhat better
negatives. To record the IR wavelengths Kodak High Speed Infrared film should
be used. It is also about the only IR emulsion readily available! Since the
film has no antihalation backing allowing light and IR to pipe into the
cassette it should be loaded into the camera in total darkness or under subdued
fluorescent illumination. Fluorescent tubes usually are very weak in IR output
diminishing the chance for fogging the film by IR rays passing into the
cassette.
When attempting either UV or IR photography the subject must be lit with lights
which emit the wavelengths by which we wish to photograph.Electronic flash is a
good source of both UV and IR wavelengths. Some flashes have a UV absorbing
filter incorporated in the flash head and this may need to be removed (if
possible) for best results. However, even if not removed, there is usually
enough UV that "leaks" through so that at close range they still serve as
useful UV sources. Then, placing a UV transmitting filter (Wratten 18A) or IR
transmitting filter (Wratten 87 or 87C)over the camera lens will effectively
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expose the film only to the wavelenghths of interest.
Under certain conditions it is possible to previsualize the approximate
appearance of a UV scene by installing into the camera a groundglass covered
with a fluorescing substance. The UV energy passing through the lens causes
this substance to fluoresce and the UV scene becomes visible in the finder!
In order to continue to use a 35mm SLR camera for reflected IR photography even
when you use the visually opaque 87 filter for photography it is possible to
install the filter behind the camera's mirror mechanism and composition of the
IR picture becomes almost as easy as if you were using "light" for your
pictures. In some cameras with behind the mirror metering systems the filter
may need to be positioned just in front of the film between the film plane
guide rails. Metering off the film may be impossible.
While exposure is most appropriately determined in either case by making a set
of test exposures or by bracketing it may be possible to establish a UV or IR
"personalized speed index" by using one of the new ultrasensitive light meters
but metering through the UV or the IR filter and correlating the exposures that
seem to deliver negatives which you judge acceptable by your own standards with
those suggested by the meter. You should generally only attempt to establish
this personalized speed index metering in the reflected mode. Finally this does
not preclude bracketing but you may more consistently arrive at the proper
exposure with less waste.
The focal length of a given lens "changes" with wavelength and for this reason
its focus should be adjusted slightly when attempting to use it for other than
light wavelengths. The lens must be moved somewhat further from the film than
visual focus demands when photographing by IR and generally also when
photographing by UV. The reason for this is that most camera lenses are
achromatic in color correction (unless otherwise stated to be simple, very
unlikely, or apochromatic in correction) and thus curve the chromatic focal
plane about two visible (except in some cases with lenses intended specifically
for UV photography) wavelengths thus bringing both IR and UV to a focus further
from the film plane than visible wavelengths. Under normal conditions the use
of small apertures will in most cases diminish or eliminate the need to make
this focus adjustment. When using a fluorescing screen in UV photography the UV
rays are properly focused when the image on the screen is sharp.
I've already mentioned the term "fluorescence", and most of us are aware of the
term but may not be quite sure of what process is at work. When some subjects
are illuminated by certain wavelengths they reflect back not only the same
wavelenghts that they are illuminated by but they may transform some of these
incident wavelengths into usually longer ones. In a sense they change the color
of the light falling on them. When a subject behaves like this it is said to
FLUORESCE. Some subjects change short, ultraviolet energy into longer, visible,
wavelengths or colors. Others may change visible rays into yet longer, infrared
wavelengths. The former effect is, of course, visible while the latter is not.
This is the realm of FLUORESCENCE photography and to apply it you need to start
with a source that contains the wavelengths which the subject will transform
into longer wavelenghts. Usually over this source is placed an EXCITER filter
the function of which is to allow only those wavelenghts through which will
cause fluorescence. In UV work this is most commonly the Wratten 18A filter and
in the visible region of the spectrum the Corning filter #9788 can be used. To
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photograph fluorescence excited by UV, which usually results in a visible
effect, color film can be used to good advantage with Kodachrome 64 being
paricularly suitable. Since not only the "new", visible, wavelenghts are
reflected from the subject but also some of the UV transmitted by the exciter
filter, a UV blocking filter, called a UV barrier filter, is placed over the
camera lens to allow the film to record only the fluorescence. For UV work this
barrier filter is the 2E or similar, pale yellow, filter. Exposure may possibly
be metered in the camera especially with the newer more sensitive in-camera
meters. No focus compensation is necessary.
To photograph IR fluorescence (or as H.Lou Gibson calls it: IR luminescence)
the B&W infrared film should be used. The exciter filter placed over the light
source must not allow any infrared rays through to the subject. The Corning
9788 is just such a filter and it can be obtained from the Corning Corporation.
It is a glass filter and since it will be used over the light source it can be
of low optical quality. Even so, it is almost as expensive as the 18A filter
(which should be of optical quality) although for a much larger size. Six
inches square vs. three inches square for the 18A, at a price of about $100 for
the 9788 and $150 for the 18A. The barrier filter should be a deep red or
infrared filter such as the 87 or 87C. Camera focus should be adjusted as per
previous discussion. Metering is not possible because the effect ocurrs in the
IR and most meters are designed to meter light, not infrared. Even meters with
IR metering capability would probably fail to detect the presence of IR
fluorescence because of the very low amounts of IR produced in this fashion.
The four techniques briefly summarized above have widespread application in
document investigations and forensic photography, in surveilance and in
environmental studies. Also in medicine, mineralogy, philately, art
history,etc. Generally one sets out on a voyage of discovery when faced with a
new subject. One tries each method in turn, hoping that one of them will yield
better information about the subject than that which the unaided eye can
perceive. Each new subject becomes a most exciting photographic adventure.
TO PHOTOGRAPH BY REFLECTED ULTRAVIOLET
The sample is illuminated by "white" light and an 18A filter is placed over the
camera lens, tightly fitted. If the subject does not fluoresce then you can
place the filter over the light but you need to work in a dark room.
This technique is useful for the photographic enhancement of rashes and other
skin disorders and also for detecting alterations in documents, etc.
Suggested light source: Electronic Flash (best if flash does not have UV
absorbing coating)
Filter on camera
: 18A
Appropriate Film
: Most any B&W film, especially slower emulsions
Lens
: Should be able to transmit UV. Most camera
lenses are suitable for long wave UV associated
with use of 18A filter over lens.
Under special conditions, such as when a short wave UV source is available,
photography is done in the dark and the 18A filter is not used. Subjects that
fluoresce will be recorded as a mixture between reflected UV and visible
fluorescence. When photographing with short wave UV (around 254nm or less)
energy, typically provided by special sources, many standard camera lenses are
file:///C|/faq.html (121 of 555) [7/19/2002 3:46:25 AM]
unsuitable because the glasses they are made of absorb such wavelengths. Quartz
or mirror lenses may need to be used although pinholes and some plastic lenses
are an alternative. Under very short wave UV conditions the gelatin of the
emulsion itself may absorb the incident rediation. In this case special
emulsions with silver halides deposited on the surface are used.
Exposure
Focus
: Generally determined by trial.
: Camera focus must be adjusted for critical use.
TO PHOTOGRAPH FLUORESCENCE EXCITED BY UV RADIATION
In its most common practice the sample must be irradiated with UV rays and due
to fluorescence it will "GLOW" in the visible region of the spectrum. The
sample will appear in various colors as a result of the effect the sample has
on the incident energy. Because samples also reflect some UV as well as
fluorescing, the unwanted UV is removed with a "barrier" filter opaque to UV.
The filter which limits the incident energy to a desired spectral region is
known as the "exciter" filter. This technique is particularly useful for the
identification of minerals and for "fingerprinting" documents such as stamps
and currency. It is also used in forensic work with fluorescing powders in
fingerprint visualization.
Light source suggested
: Electronic Flash or UV emitting lamps
operating in a darkened environment.
Exciter filter suggested: with lamps it's built in so none needed
with electronic flash use 18A over flash.
Barrier filter suggested: Wratten 2A or 2E
Appropriate film
: Color reversal daylight film seems best.
Effect is in color so B&W film less useful.
Exposure : Can often be determined with built in meter but light level
is much lower than it might appear visually.
Focus
: Visual focusing on groundglass possible.
TO PHOTOGRAPH BY REFLECTED INFRARED
The sample can be illuminated by "white" light and an 87 or 87C 9or similar)
filter is placed over the camera lens, tightly fitted. In a darkened room the
filter may be placed over the light source. Sometimes a filter is not required.
For example, a flatiron may be used as a source of IR radiation and if
operating in a dark room no filters are needed.
Some photographers use a #25 filter over the lens of SLR cameras in particular
so that they can focus on the image in the groundglass. Alternatively, the
visually opaque IR filter may be inserted behind the camera's mirror.
This technique is useful for the recording of subcutaneous (below skin) veins,
for the detection of alterations or forgeries of documents, for
surveilance,etc.
Light source suggested : Electronic Flash, floodlights or daylight.
Filters suggested
: 87 or 87C over camera lens.
Film
: Kodak High Speed Infrared
Exposure : Determined by trial, use manufacturer suggested data,
or using CdS Luna Pro and metering through 87C filter
set ASA guide to a speed of 2400.
file:///C|/faq.html (122 of 555) [7/19/2002 3:46:25 AM]
Focus
: For critical results it must be adjusted.
TO PHOTOGRAPH FLUORESCENCE EXCITED BY LIGHT IN THE INFRARED (LUMINESCENCE)
As in fluorescence excited by UV certain samples transform shorter wavelengths
into longer ones which in this case are in the invisible IR region. This
effect is sometimes called "luminescence" and the sample is usually irradiated
with BLUE-GREEN light without any IR present in the beam. A barrier filter
which allows only the newly created IR wavelengths to pass into the camera is
placed over the lens. Best to work in a dark, IR free, environment.
This technique is particularly useful for the study of inks, hardwoods and
forgery detection in forensic photography.
Light source suggested : Tungsten or Electronic Flash.
Exciter filter suggested: Corning 9788 over light source plus Corning
3966 heat absorbing filter placed between
source and the 9788 if using tungsten source.
Certain blue-green lasers also may be used
without any filters.
Barrier filter suggested: Wratten 87, 87C or 88A
Film
: Kodak High Speed Infrared
Exposure : Determined generally by trial. Expect it to
be extremely great.
Focus
: Must be adjusted for critical results.
Note: when IR reflected light photography is done with COLOR INFRARED film,
then "white" light plus IR must fall on the sample, thus a Wratten #12 is used
over the camera lens to remove from the incident radiation the blue light to
which the three layers of the IR COLOR film are all sensitive.
================================================================================
Note 21.08
-< Solarization Tip >-------------------------------------------------------------------------------There was an interesting suggestion posted on the Internet that I thought
might be of help if you are trying your hand at solarization (Sabattier).
<[email protected]> writes:
> My students just finished using dektol and Ilford Multigrade rc with
> a #5 filter and a #5 filter in the white light source. They all seemed
> to get pretty good results.
That would make sense...under those conditions, a Variable Contrast
emulsion becomes essentially a single-layer graded emulsion. (The second,
green-sensitive, low-contrast layer is completely out of action.) I
had tried the #5 filter in the image light, but not on the fogging
light. I'll try that...
Richard Hosker
[email protected]
================================================================================
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Note 21.09
-< Create-a-Print used for B&W printing >-------------------------------------------------------------------------------> Has anyone figured out a way to use black and white negatives other than
> xp2 in the create a print? It doesn't seem to want to accept non-bar coded
> negatives, and i was wondering if there was a way to override this...
It's pretty easy. Right above the negative eject symbol is a number,
most often '1' but it depends on the last type of film inserted in the
Create-A-Print. Using the diamond key with the arrows (triangles) on
it, move the cursor on top of that number and rotate the zoom control
(one on the right) til the number gets to '40' .. turn it either right
or left until it gets to '40'. Then hit the button with the yellow
circle on it and the machine is now set for B&W film. You may need to
turn that up or down while you are using the machine, using 41 or
whatever (I think XP2 is 49) until you get the right color correction
on the screen. It will not be perfect at first, but make your own
color corrections. Good luck,
Robert E. Klimkiewicz, Jr. -- Communication Major
George Mason University Fairfax, Virginia U.S.A.
<[email protected]>
================================================================================
Note 21.10
-< Decoding De DX Code >-------------------------------------------------------------------------------DX codes decoded
>1) Does any one have a clear view of the DX coding? What means what and how it
>is used. Especially interested in the meanings of each of the squares.
This info was transcribed from the June 1983 issue of "Modern Photography",
page 8, by Markus Wandel <[email protected]> and he posted on rec.photo.
========================= <-- Light trap
+---+---+---+---+---+---+
+-| 1 | 2 | 3 | 4 | 5 | 6 |
Bottom --> | +---+---+---+---+---+---+
<-- view of the film cartridge
|_| 7 | 8 | 9 | 10| 11| 12|
+---+---+---+---+---+---+
------------------------The DX coding surface is divided up into 12 squares as shown. Squares 1 and 7
are ground, i.e. they are always bare metal. The remaining squares are encoded
as follows ("*" means bare metal, otherwise square has nonconductive paint):
FILM
SPEED 2 3 4 5 6
---------------25
*
32
*
40
* *
50
*
*
64
*
*
80
*
* *
100
*
*
FILM
LENGTH 8 9 10
-------------12
*
20
*
24
* *
36
*
*
*
* *
72
* * *
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EXPOSURE
LATITUDE
11 12
---------------+/- 1/2
+/- 1
*
+2/-1
*
+3/-1
* *
125
160
200
250
320
400
500
640
800
1000
1250
1600
2000
2500
3200
4000
5000
*
*
* *
* *
* *
*
*
*
*
*
*
* *
* *
* *
*
*
*
*
*
*
*
*
*
*
*
*
*
* *
*
*
* *
*
*
* *
*
*
* *
*
*
* *
*
*
* *
================================================================================
Note 21.11
-< IR Ektachrome Processing in cool E6 chemicals >-------------------------------------------------------------------------------How to process Ektachrome Infrared in E6 chemicals
While it is true that E-4 chemicals should be used to process this
film, it can be processed with E-6. That is, if you can tolerate
somewhat weird colors.
To process with E-6 first all temps must be at 75 degrees fahrenheit
time(min.)
first developer
-wash
reversal bath
color developer
conditioner
bleach
fixer
-wash
stabilizer
10
2
2
8
2
10
10
6
2-3
I have developed the two rolls that i was able to find like this.
The results were fantastic, if only in an artistic sense.
Note 22.01
-< Sunrise/Sunset location finder BASIC program >------------------------------------------------------------------------------->Can someone point me to a source of tables or calculations for determining at
>what compass point the sun is going to rise on a given day at my latitude?
* please note that at the bottom of this contribution there is word of warning
about the "simplicity" of this program esp. when used in exteme situations.
file:///C|/faq.html (125 of 555) [7/19/2002 3:46:25 AM]
This is a little BASIC program that will do this. It's quite simple, and makes
some assumptions that may be slightly erroneous. For example it assumes that
the earth is perfectly spherical and that the sun is an infinite distance away
from the earth, neither of which are true. And it makes no allowance for uneven
terrain. However it should give results accurate to within a degree or so.
Since even the best compasses generally available are calibrated in increments
of 5 degrees, it should be adequate for setting up photos in advance.
Note that the answer is given in TRUE degrees, which must be converted to
magnetic according to your local variation. In North America, magnetic heading
= true - variation (around 20 deg.)
I thought it might also be useful to know the angle at which it rises and sets,
which can be quite steep. For example, if you wanted to get a picture of the
sun rising over a steeple, at that height it may have moved quite a few degrees
North or South of the rise point. So that's another thing to consider. Please
verify the answers this thing gives before making plans for a complicated photo
I take no responsiblity for it's accuracy, useful- ness, or lack of same. It
doesn't predict the time. You can find that in the newspaper or the evening
news.
If you want to know how it works, it's based on the fact that the sun is far
enough away that it appears to rise for everyone from the same direction. In
other words, on one of the equinoxes the sun is directly over the equator. If
you were standing at the equator that day, it would appear to rise due East.
But if you were in Alaska that day it also appears to rise due East, it just
doesn't get anywhere near as high (the rise angle is different). On the other
hand, on June 22 it rises 23.5 degrees North of due East. Again, it doen't
matter whether the observer is at the equator, the arctic circle, or the
Southernmost part of Australia. This makes things fairly simple.
The rise/set angle is easy to find, because it's the same as the maximum angle
that the sun will be at noon. Said another way, the angular height of the sun
at noon is the same as the angle it makes with the horizon near sunrise/set
looking due East or West.
The basic equation used to find the heading is:
sun angle = sin (d) * 23.5
Where 23.5 is the angle (in degrees) of the Ecliptic plane to the
Earth's equator, and d is the degrees of movement of the Earth in
it's yearly revolution around the sun. Conveniently, this is almost
exactly the same as the number of days (360 degrees ~= 365 days).
Day zero is considered Mar. 22. For better accuracy, days are converted to degrees by the factor 360/365.25. Since most computers
use angles in radians, degrees are converted to radians by dividing by 57.3. (if your computer uses degrees, delete the first
part of line 40 and use the second half. The resulting sun angle
I round to the nearest degree.
This is the angle of the sun with respect to the equator, from a viewpoint
external to the Earth. This number is subtracted from the nominal heading of
90 degrees (East) for the rise heading, and added to the heading of 270 degrees (West) for the set heading. The rise/set angle is simply the difference
file:///C|/faq.html (126 of 555) [7/19/2002 3:46:25 AM]
between the sun angle and your latitude. Before giving an answer, some simple checks are done to make sure there actually will be a sun rise/set that
day, in case you're close to one of the poles. That's about it. Corrections
are welcome.
10 print "Sunrise/set Bearing Predictor, D. Richards 2/13/92":print
20 input "Number of days after Mar. 22: ";day : deg=day*360/365.25
30 input "Latitude (N assumed -- South is minus): ";lat
40 sunangle=int(sin(deg/57.3)*23.5+.5) :'40 sunangle=int(sin(deg)*23.5+.5)
50 if lat-sunangle >= 90 then print "The sun will not rise here this day.":end
60 if lat > 90-sunangle then print "The sun will not set here this day.":end
70 print "true sunrise heading = ";90-sunangle
80 print "true sunset heading = ";270+sunangle
90 risangle=lat-sunangle
100 if risangle=0 then print "Sunrise/set angle will be vertical.":end
110 print "Sunrise/set angle will be ";abs(risangle);" degrees from vertical";
120 if risangle>0 then print " toward the South.": end
130 if risangle<0 then print " toward the North.": end
Dave
From: [email protected] (Dave Richards)
Organization: Action Capture Costa Mesa, CA
From:
IN%"[email protected]"
1-SEP-1994 08:51:38.80
I stumbled across the sunrise/sunset contribution in the PhotoForum's
FAQ-file (FAQ-22.01). The programm is indeed nice and simple, but I'm sorry
to have to tell you that it's _too_ simple. The assumptions made (earth
spherical, sun at infinite distance) are fine --- the error they result in
(< 1 minute of arc) are negligible when compared to the (errors that are
_unavoidable_ when calculating the) effects of refraction.
The real bug is, that, while it is true that the sun rises in the same
direction for everybody during the equinoxes, this isn't true on all the
other days (and at the poles, since there you only have the direction "south"
[respectively "north"]) --- if it were, then the earth would look
like a cylinder, between the arctic and antarctic circles, with an
undefinable top [bottom] changing it's shape in the course of a year.
The problem with sunrise/sunset calculations is that they can't be done
without _spherical_ trigonometry. If I use this programm for the 23rd
of March at a latitude of 89 deg. north, I get 90 deg. as the heading
at sunrise with a riseangle of 89 deg. --- a programm resident in our LAN
(which does all the calculations we need to point our telescopes and a
lot of other useless things) gives me 29 deg. as the heading and a riseangle
of 5 deg.(BTW sunrise is at 2:00 local solar time).
It's a pity that I've got plenty of things to do until sunday --- before
I'll vanish in the Auvergne (France, Massif Central) 'til the end of
September --- or I'd take a look in our library. I believe there was a
relative short programm doing simple sunrise/sunset calculations in one of
the three (four ?!?) last copies of Sky & Telescope magazine.
*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_
file:///C|/faq.html (127 of 555) [7/19/2002 3:46:25 AM]
Klaus Bagschik
Radioastronomischs Institut
der Universit"at Bonn
D-53121 Bonn
(Fed. Rep. Germany)
phone: +49-228-73-5658
fax:
+49-228-73-3672
e-mail: [email protected]
"Per aspera ad astra!"
_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*_*
================================================================================
Note 22.02
-< Simple Sound Switch to trigger Flash >-------------------------------------------------------------------------------+9v
This device will trigger a flash upon
o---.
^
+ 10uf
sensing a sound. Input should be a small
|
| .-|(--.
speaker or large ceramic microphone. The
|
| |
|
386 amp is set to 200x gain. The 3011 is
^
|
6| |1
8|
an optocoupled switch.
Could use 3010.
|
.--*--*-----*-.
I
\10Kohm |
|
.----------.6
N
/
3|
|5
10uf +
1|
*-----> to flash
P
\<-------*
LM386
*---*---)|------*
3011
|
(by PC)
U
/
|
|
|
|
*-----> to flash
T
\
|
|
Z 10 ohm
|__*_______|4
/
|__*___*___*__|
|
2|
v
|
2| 4| 7|
=== .1 uf
|
|
|
|
|
|
|
o___|___________|___|___|______|______________|________> -9v
================================================================================
Note 22.03
-< Make Black Borders or Lines around your images >-------------------------------------------------------------------------------> Does anyone have any good tricks for burning in black borders around a B&W
> print? Do you need a special easel or process for doing this?
To make black borders to the edge of the paper make yourself an opaque mask the
size of the desired image area. Actually tranparent red masks work even better.
When you make the enlargement make it a bit bigger than the mask you've cut.
After the paper is exposed to the image place and fix the mask onto the paper
in the correct position and with no negative in the enlarger use the enlarger
as a light source to burn in the edges. When you do this you would be working
without the easel.Or with it if you can afford a thin white border on the final
print. This white border would, of course, be covered by the mat.
If you want a thin, black line to go around your image area the concept is the
same but the mask this time cut so it is a little smaller than the easel's
opening, goes over the image area after your image was exposed. Then you remove
the negative from the enlarger and burn in the line between the mask and the
easel edges. If the mask is a little larger than the print area then you make a
thin white line. Combinations of masks and sizes let you get quite creative
with borders and/or lines.
Andy
From: [email protected]
Organization: Rochester Institute of Technology
file:///C|/faq.html (128 of 555) [7/19/2002 3:46:25 AM]
I use Speed-E-Zels mostly, and I cut red construction paper masks that I slip
in the easel over the paper. I have masks in both 8x10 and 11x14 size. I cut a
rectangle in an 8x10 size sheet of red paper, then I trim off about 3/16 inch
from each dimension of the "hole". (You want to make those borders as thin as
possible.) I compose with the large red mask in the easel, leaving just a
little more room than normal. Then I expose with the paper under the mask. I
then position the rectangular insert so that there is an even distance on all
four sides. I take the negative out of the carrier and expose the "border" for
about 5 seconds. This produces a thin black border around the print with a
large white border. With the combinations of mask and insert, you can have a
large black border, a large white border, or the previously described large
white with thin black border.
I have masks of several different aspect ratios: 5 x 10", 7 x 10, 7 x 9, 7 x 7.
This allows customizing the image to the frame. For some of the aspect ratios,
I have two versions, one for a horizontal image, and the other for a vertical
image.
From: [email protected] (mark.e.fohl)
Organization: AT&T
================================================================================
Note 22.04
-< Sound Synchronizer for ECM application >-------------------------------------------------------------------------------Here is a schematic for a Sound Synchronizer designed for use with an ECM
(electret condenser microphone).
+6v
+6v
^
^
+ 10uf
_ |
| .-|(--.
*----> flash (hot)
| | |
| |
|
| a
|--| |-/
6| |1
8|
_|_
|_|
.--*--*-----*-.
\ / TIC106D
| 20Kohm |
|
__V__
|
3|
|5
100uf +
g /|
+-2V -->*----||--*
LM386
*---*---)|--------/ | c
+ | .01uf |
|
|
*----> flash (GND)
|O ECM
|
|
Z 100 ohm
|
- | mic.
|__*___*___*__|
|
|
|
2| 4|
7
=== .047uf
|
|
|
|
|
|
|___________|___|__________|_______________|________> 0 v
|
--- GND
For the ECM to work, you'll need about +2v at the point shown in the
schematic, this can obtained by trimming the +6v down with the 20k lin. pot.
But this might vary with the type of ECM used. Observe polarity of the ECM.
This circuit is fairly sensitive, but I'm working on some improvements...
From: Jeroen Steenblik
[email protected]
file:///C|/faq.html (129 of 555) [7/19/2002 3:46:25 AM]
================================================================================
Note 22.05
-< Pinout Layout for Carousel Projector Receptacle >------------------------------------------------------------------------------->I was wondering if anyone knows the pinout for the dissolve/lamp control port
>on Kodak carousel slide projectors? I'm referring to the rectangular
>connector with one rounded end; the one you typically connect to an external
>dissolve unit (NOT the remote control connector).
This is described in a couple of pamphlets that were published by Kodak:
Kodak Slide Projector Wiring and Operation, Cords, Plugs and Receptacles for
Kodak AV Equipment, Reducing or Controlling Ligth Output of Kodak Ektagraphic
Projectors. Kodak may still have these available through their Info Service
reachable at 800-242-2424.
In the last pamphlet there is an indication that placement of a switch, switch
plus resistor (fixed or variable), or diode between the two sockets located
directly below the 5 pins devoted to the "remote" control will allow you to
control the light level. Proper consideration of power requirements must be
taken. This is explained in detail in the pamphlets.
I transcribed the illustration for you:
__________
/
\
Small Red (forward
/
\
and chassis ground)----/--> o
o <--\---- Small Black (focus)
|
o <------|--- Yellow (common -- not ground)
Small White (reverse)-|--> o
o <--|--- Brown (focus lock)
|
|
|
|
Large Red -----|--> o
o <--|--- Blue (to lamp)
(to power switch) |
|
| ............. |
| : O
O : |
| :...........: |
|________/________|
/
/__ Not used with projectors having
permanently attached power cords
Andy
================================================================================
Note 22.06
-< Foot-candles - how to measure them? >------------------------------------------------------------------------------->My mother in law grows orchids and for some reason needs to measure the amount
>of light falling on them in foot-candles. All the light meters she has are
>graduated in ASA or somesuch. How can she measure in foot-candles with them?
The illuminance at the surface of the earth due to the sun at zenith on a clear
day is about 10,000 footcandles. These same conditions are associated with the
"sunny sixteen" exposure rule of 1/ASA seconds at f/16. You can use this as the
basis to compute other values of illuminance.
For example:
file:///C|/faq.html (130 of 555) [7/19/2002 3:46:25 AM]
Set a light meter for ASA 10,000 and take an incident reading (or a reflected
reading of an 18 percent gray card) of the garden illumination. The value in
footcandles will be approximately equal to the inverse of the exposure time in
seconds; e.g. 1/60 second is 60 footcandles, and 4 seconds is 1/4 footcandle.
From: [email protected] (Chris Ellinger)
Organization: Kresge Hearing Research Institute
================================================================================
Note 22.07
-< Film Acceleration >-------------------------------------------------------------------------------From: [email protected]
Subject: Color Acceleration
Organization: Utah State University
This is a copy of an article that I read in Photographic/November 1992.
-------------------------------------------------------------------------------by Marc S. Bloom
ASSIGNMENT: Film acceleration is a Color III assignment at Brooks
Institute of Photography. The process drastically increases film speed, but it
also radically changes the characteristics of the film; most notably, color
balance and grain.
CHOOSING THE FILM: Select an E-6 transparency film and expose it at a
higher EI (exposure index). Keep in mind that selecting a medium-speed film
over a high-speed one will result in less grain. In choosing the EI, I
recommend a two-stop increase; for instance, from ISO 100 to EI 400. This
procedure can be done with color negative film, as well, but transparency film
will enhance the grain effect.
PROCESSING THE FILM: Follow these simple steps in order, for both
color-slide and color-negative films.
Step 1:
presoak the film in water (75 degrees farenhite) for two minutes.
This will yield more even development. Agitation will release air
bubbles that may adhere to the film surface upon immersion.
Step 2: Develop in either Acufine, T-Max, or Perfection XR-2 developer. Refer
to the chart for times and tempatures. Agitate normally, as you woul
in developing black-and-white film (per your normal procedure).
Step 3: Rinse in water for one minute, with agitation. This will replace the
acid stop bath.
Step 4: Fix the film in non-hardening fixer for five minutes. Color-film
fixer, Rapid fixer without the hardening agent, or a fixer made from
Sodium Thiosulfate crystals, will work well.
Step 5: Wash the film for ten minutes, with intermittent agitation. From this
point on, you may expose the film to room light.
Step 6: Bleach for ten minutes. I recomend using E-6, C-41, or E-4 bleach
solution. Refer to chart for homemade version.
Step 7: Wash your film for atleast ten minutes. Do not use Photo Flo solution
or other wetting agents
Step 8a: Bring your film to any profesionale lab to have it processed normally
in C-41 chemistry. (Don't have the lab push process your film.) You
can bring the film to the lab in the processing tank, wet, or you can
dry the film for easier transport.
Step 8b: If you choose to dry the film, rinse your film in deionized water,
file:///C|/faq.html (131 of 555) [7/19/2002 3:46:25 AM]
with two or three vigrous tank inversions, then squeegee dry. If your
lab questions your strange looking film, tell them that it will not
harm their chemistry. The film will look badly underexposd, but this
is normal. If you have rinsed your film for atleast ten minutes, and
refrained from using Photo Flo in your final rinse, the C-41 chemistry
will not become contaminated.
SHOOTING: Shooting a faster film will heighten the grain effect.
RESULT: As you can see from the image, you don't get the normal tonal
rendition that you would if normally processed the film. After you havr
processed you film and sent it to the lab for C-41 processing, you will have an
unmasked color negative. It is no longer a transparency.
PRINTING: In the printing make sure that the lab knows to print for
skin tone. That way, everytging else in the photograph will not have any true
color rendition. The results are fascinating!
CHART
----FILM
Ektachrome
Ektachrome
Ektachrome
Ektachrome
Ektachrome
Ektachrome
Ektachrome
Ektachrome
Fujichrome
Fujichrome
Fujichrome
Ektachrome
100
200
200
200
160
400
400
400
400
400
400
400
EI
400
400
800
1600
320
800
1600
3200
800
1600
3200
3200
DEVELOPER
Acufine
Acufine
Acufine
Acufine
Acufine
Acufine
Acufine
Acufine
Acufine
Acufine
T-Max
XR-2
TIME
12min.
9min.
12min.
16min.
9min.
9min.
12min.
16min.
10min.
13min.
14min.
12min.
TEMP
75deg.
75deg.
75deg.
75deg.
75deg.
75deg.
75deg.
75deg.
75deg.
75deg.
75deg.
86deg.
ACCELERATION FILM BLEACH
Start with 750ml of water at 75deg.. With constant stirring, add the
following: Potassium Ferricyanide (30 grams), Potassium Bromide (10 grams), and
water to make 1 liter.
FROM:
CAM
IN%"[email protected]"
================================================================================
Note 22.08
-< IR Film Data Sheet >-------------------------------------------------------------------------------Kodak High Speed Infared Film 2481
(Estar Base)
* A high-speed, infared-sensitive black-and-white film on
dimensionally stable .004-inch (0.10nm) Estar Base.
* Sensitive through the visible region of the spectrum and in the
infared to approximately 90nm, with maximum sensitivity from 750nm
to 840nm.
* Used in scientific, medical, biological, industrial and
questioned-document photography.
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HANDLING: Handle only in total darkness. No safelight should be
used.
EXPOSURE
FILTERS: For most applications, a filter must be used over the lens
(or light source) to absorb the blue light to which the film is
sensitive. For general photography, a KODAK WRATTEN Filter No. 25
is recommended for this purpose. If only infared is to be recorded,
use a KODAK WRATTEN Filter No. 87, 87C, 88A or 89B or its
equivalent. Under very low light conditions and when infared
rendition is not important, the film can be exposed without a
filter.
FILM SPEED: Exact speed recommendations are not possible because
the ratio of infared to visible radiation is variable and because
photoelectric meters are calibrated only for visible radiation. Use
a hand-held meter rather than a through-the-lens type.
It is recommended that trial exposures be made to determine proper
exposure for the conditions under which photographs will be made.
Under average conditions, the following speeds can be used as a
basis for determining exposures when meters marked for ASA speeds
or exposure indexes are used.
SPEEDS FOR RECOMMENDED DEVELOPMENT IN KODAK DEVELOPER D-76:
KODAK WRATTEN FILTERS
DAYLIGHT
TUNGSTEN
No. 25, 29, 70, or 89B
50
125
No. 87 or 88A
25
64
No. 87C
10
25
Without a Filter
80
200
FOCUSING: For best definition, take all infared pictures at the
smallest lens opening that conditions permit. If large apertures
must be used and the lens has no auxiliary focusing mark, establish
a focusing correction by photographic focusing tests. A basis for
trial is the extension of the lens by 1/4 of 1 percent of the focal
length of the lens.
DAYLIGHT EXPOSURES: -for subjects in bright or hazy sunlight
(distinct shadows):
EXPOSED THROUGH KODAK WRATTEN FILTER NO. 25
Distant Scenes
Nearby Scenes
1/125 sec at f/11
1/30 sec at f/11
NO FILTER
Distant Scenes
1/125 sec at f/16
PHOTOLAMP EXPOSURE TABLE: For use with a KODAK WRATTEN Filter No.
25 over the camera lens. Use two 500-watt reflector-type photolamps
or two No. 2 photolamps in 12-inch reflectors giving comparable
light output. Place one lamp on each side of the camera at an angle
of 45 degrees to the camera-subject axis.
Lamp-to-Subject Diatance
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3 feet
4 1/2 ft
6 1/2 ft
Lens Opening at 1/30 Sec.
f/11
f/8
f/5.6
FLASH EXPOSURE: To obtain the lens opening for electronic flash or
flashbulbs, divide the guide number by the distance in feet from
flash to subject.
ELECTRONIC FLASH GUIDE NUMBERS: Use with a KODAK WRATTEN Filter No.
87 over the camera lens:
Output of Unit
(BCPS or ECPS)
350 500 700 1000 1400 2000 2800 4000 5600 8000
Guide Number for
Distances in Feet
24
30
35
40
50
60
70
85
100
6
7
9
11
12
15
18
24
26
30
Guide Number for
Distances in Meters
20
PROCESSING PROCEDURE
1. Develop:
Approximate Developing Time (in minutes)
Kodak Dev
Aprox
Contrast
SMALL TANK-(agit at
30-sec intervals)
65F 68F 70F 72F 75F
18.5C 20C 21C 22C 24C
D-76
LARGE TANK*-(agit at
1-min intervals)
65F 68F 70F 72F 75F
18.5C 20C 21C 22C 24C
0.70
13
11
10
9.5
8
14
HC-110
0.80
(Dilution B)
7
6
6
5.5
5
7
D-19 (maximun contrast)
7
6
5.5
5
4
8.5
1.65
12
6.5
11
9
5.5
5
6
10
7.5 6.5
6
*Development times of less than 5 minutes in a large tank may
produce poor uniformity and should be avoided.
5
2. Rinse:
At 65 to 75 F (18.5 to 24 C) with agitation.
Kodak Indicator Stop Bath - 30 seconds.
OR
Kodak Stop Bath SB-5
- 30 seconds.
A running-water rinse can be used if an acid rinse bath is not
available.
3. Fix:
At 65 to 75 F (18.5 to 24 C). Agitate films frequently during
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fixing.
Kodak Rapid Fixer
OR Kodak Fixer
OR Kodak Fixing Bath F-5
-2 to 4 minutes
-5 to 10 minutes
-5 to 10 minutes
4. Wash:
For 20 to 30 minutes in running water at 65 to 75 F
C). To minimize drying marks, treat in Kodak Photo-Flo
after washing, or wipe surfaces carefully with a Kodak
Chamois or a soft wet viscose sponge. To save time and
water, use Kodak Hypo Clearing Agent.
(18.5 to 24
Solution
Photo
conserve
5. Dry:
in a dust free place.
STORAGE:
Keep unexposed film in a refrigerator or freezer at 55 F (13C) or
lower in the original sealed container. If the film is stored in a
refrigerator, remove it four hours before opening the package. If
stored in a freezer, remove it about eight hours before opening. A
sufficient warm-up time before opeing the package is necessary to
prevent condensation of atmospheric moisture on the film.
Keep exposed film at 40 F (4 C). Process the film as soon as
possible after exposure to avoid undesirable changes of the latent
image. If it is necessary to hold exposed but unprocessed film for
several days, it should be resealed and refrigerated. Before
unsealing and processing exposed film that has been stored in a
refrigerator or freezer, follow the moisture prevention and
handling procedures for raw film as described above.
FOR MORE INFORMATION: see the following Kodak Publications
No. M-28, Applied Infared Photography
No. N-1, Medical Infared Photography
No. N-17, Kodak Infared Films
NOTICE!
This film will be replaced if defective in manufacture, labeling or
packaging. Except for such replacement, the sale or any subsequent
handling of this film is without warranty or liability even though
defect, damage or loss is caused by negligence or other fault.
Eastman Kodak Co, Rochester, NY
14650
Kodak, Estar, Wratten, D-76, HC-110, D-19 and Photo-Flo are
trademarks.
================================================================================
Note 22.09
-< Circular Polarizers - better than square ones? >-------------------------------------------------------------------------------From: [email protected] (Bruce Bowen)
Subject: Circular polarization, what and why.
Organization: Megatest Corporation
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> I understand how a polarizer works, can somebody explain to me how a circular
> polarizer works please? Should I have spent the extra money for this?
What:
CIRCULAR POLARIZATION:
Circular polarization is a form of polarization for light (and other
transverse 2-D waves) where both horizontal and vertical components are
present, but they are coherent with each other and 90 degrees out of
phase. So instead of going "up and down", or "right and left" as in
linear polarization, you get a field vector that rotates in a circle,
either CW or CCW, and never goes through zero.
For example, if you take a clothesline, tied at one end, and wiggle it
up and down, you get a linearly polarized standing wave, if you rotate
it around in a circle like a jump rope you have a circularly polarized
standing wave.
Why:
Modern autofocus cameras employ dielectric beam splitters in their
autofocus mechanisms. These are sensitive to, and don't work properly
with, linearly polarized light (for those of you who are familiar with
optical refraction and reflection, think "Brewster angle").
In order to get the advantages of a linear polarizing filter with a
modern autofocus camera, you use a linear polarizing filter with a
second coating on the back that de-"linear polarizes" the light after
the other linear component has been filtered out. This second layer
turns the linear polarized light reaching it to circular polarized
light, which is compatible with the beam splitters.
Fun things to try:
I've never done this, but it should work. Take two circular polarizing
filters. Have their fronts facing inward toward each other. As you
rotate one with respect to the other you will see the normal linear
polarizing effect of it going light and dark every 90 degrees (so, what
else is new). Now take the far filter and turn it arround so that the
front of the near filter is facing the back of the far filter. Now as
you rotate around, nothing will happen (or it may still go through
the light and dark cycles, but not as intensly.)
Note 23.01
-< Speed Graphic FAQ file >-------------------------------------------------------------------------------From:
IN%"[email protected]" "Tim Takahashi" 4-JUN-1994 19:47:35.33
Subject: The GRAPHIC and GRAFLEX FAQ
Here is the version received on June 4, 1993:
THE GRAPHIC / GRAFLEX FAQ FILE
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Editors: William Caloccia and Timothy Takahashi
<[email protected]> <[email protected]>
with additional material from
Ronald Wisner <72072,[email protected]>
Roger Paulson <[email protected]>
David Rosen
<[email protected]>
Mike Rosenlof <[email protected]>
Thorn Roby
<[email protected]>
David Smigelskis <[email protected]>
Related Newsgroups:
rec.photo
Revision History
---------------Initially Released:
Lenses updated
March 10, 1994
March 17, 1994
wpc, tt
ds, tt
=========================================================================
INTRODUCTION: Photography with GRAPHIC and GRAFLEX cameras
The is a tendency for the name 'Speed Graphic' to be used to denote
any "press" style camera. The Speed Graphic was manufactured by
Graflex, a Rochester, New York based camera producer. It was the
dominant portable professional camera from the 1930's through the
end of the 1950's.
The 'Speed Graphic' and their brethren, the 'Crown Graphic' and
'Century Graphic' are remarkable cameras capable of the highest
quality of work. The 'Speed Graphic' has not been manufactured
since 1973 and most photographers today are unable to make a
direct comparison*. In many ways, the 'Speed Graphic' was America's
first and last great camera.
The 'Speed Graphic' was engineered for general purpose commercial
photography such as wedding, portaiture, product, documentary,
advertising and landscape photography. Otha Spencer writes in
Shutterbug,
"After the war, I bought a Pacemaker Speed Graphic and
started a commercial and portrait studio. With the Speed
Graphic, a 4x5 Super-D Graflex, one reflector flood light,
one background light and a primitive darkroom, I became a
commercial photographer."
The 'Speed Graphic' camera has two shutters - focal plane and in-lens;
three viewfinders - optical, wire frame and ground glass;
interchangeable lenses; a rise and fall front; lateral shifts; a
coupled rangefinder; and a double extension bellows adaptable to lenses
from 90mm to over 300mm.
The Speed Graphic looks complicated, but is a one of the simplest
and most flexible cameras made. Afflicted by a "Rube Goldberg
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variety of features - three viewfinders! - you prove your skill
everytime you use it. Nothing in the Graphic is automated; if
you don't pay attention you can double expose, shoot blanks, fog
previous exposures or shoot out of focus images. However, once you
get used to it, it is amazingly easy to use.
The older Graflex SLR with its patented focal plane shutter and
reflex focusing had been so successful as a press camera that
the Graflex company set out to design a camera specifically for
the emerging "press" photographer. The result was the original
'Speed Graphic' of 1912.
The concept of having two separate shutters was a new idea.
The focal plane shutter was the same as used in the Graflex,
the front in-lens shutter provided extra versatility. Because
both shutters can not be used at the same time, there is possibility
of confusion. Experienced 'Speed Graphic' users find selection
of shutters second nature.
In 1940, Graflex announced the Anniversary Speed Graphic with
Kodak Anastigmat (or the then all-new Ektar) lens. The new
features included the coupled rangefinder and flash solenoid
to use the then popular flashbulb. The bed would drop past
horizontal, allowing the use of the then new wide angle lenses.
The Speed Graphic was the still camera of World War II, and
took many famous images striking today for their technical
and artistic beauty. On the home front, Arthur Fellig, aka.
Weegee, prowled the streets of New York with his Speed Graphic.
He writes in his 1945 monograph "Naked City" :
"The only camera I use is a 4x5 Speed Graphic with a Kodak Ektar
lens in a Supermatic Shutter. All-American made. The film I use
is Kodak Super-Panchro Press B. I always use a flashbulb for
my pictures which are mostly taken at night...
If you are puzzled about the kind of camera to buy, get a
Speed Graphic.... for two reasons.... it is a good camera,
and moreover.... with a camera like that the cops will assume
that you belong on the scene and will let you get behind
police lines."
In 1947, the Pacemaker Speed Graphic was introduced bristling
with new features such as a body mounted shutter release and
simplified focal plane shutter (now with 6 normal speeds rather
than the 24 speeds possible before).
The "Graflok" back, with a metal focusing hood and removable ground
glass was introduced in 1949. This back, the standard for 4x5"
view cameras today accepts sheet film holders, roll film adaptors,
the now obsolete film pack, cut film magazines (the Grafmatic) and
the Polaroid back.
The 'Speed Graphic,' like other 'press' cameras is designed to be
operated either handheld or on a tripod. In this sense, there is
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a kinship between the 'Speed Graphic' and 35mm gear. In the larger
format world "kinship to 35mm" can not be considered equivalence of
features or toys. The 4x5" Speed Graphic could not be farther from
modern 35mm gear in terms of construction or configuration. Yet with
a Grafmatic one can go shoot six successive images handheld using
shutter speeds as high as 1/1000 sec.
The company name changed several times over the years as it was
absorbed and then released by the Kodak empire, finally becoming
a division of the Singer Corporation and then dissolved in 1973.
The award winning Graflex plant in suburban Pittsford, New York
is still standing and is home to the MOSCOM Corporation.
Years
- - - - 188?-1904
1905-1927
1928-1946
1946-1955
1956-1968
1968-1973
1973
Manufacturer
- - - - - - - - - - - - - - - - - - - - - - - - - - Folmer & Schwing Manufacturing Co., NY, NY
Folmer & Schwing Div., Eastman Kodak Co. Rochester, NY
Folmer Graflex Corp., Rochester, NY
Graflex Inc., Rochester, NY
Graflex Inc., Div. General Precision Equipment, Rochester, NY
Graflex Inc., Div. SINGER CORPORATION
Tooling bought by Toyo Co.
Post 1940 Graphic style cameras may be considered usable cameras,
rather than antique or collectible cameras. The Speed Graphic was
manufactured in a number of sizes, 4x5" being the most common, but
also in 2.25x3.25" 3.25x4.25" and 5x7"
Produced
- - - - -
Model name and description
- - - - - - - - - - - - - - - - - - - - - - - - - - -
1958-1973
1961-1970
Super Graphic
Super Speed Graphic (Graflex-1000 1/1000 front shutter)
All metal body, including flash computer, electric shutter
release, front standard had swing capability, & featured
revolving back. [NO focal plane shutter !]
1947-1973
1947-1970
1949-1970
Pacemaker Crown Graphics (4x5,3.25x4.25,2.25x3.25)
Pacemaker Speed Graphics (4x5,3.25x4.25,2.25x3.25)
Century Graphic (2.25x3.25)
Post war brought coated lens and lenses in shutters, body
release, folding infinity stops. The plastic bodied 'Century
Graphic' and mahogany/metal 'Crown Graphic' were w/o focal
plane shutters. Imported 2.25" cameras led to the design of
the roll film holders, and the Graflok back (1949). Flat bar
viewfinder, followed by flexible wire viewfinder. Side mounted
rangefinder replaced by top rangefinder on 4x5" Graphics in 1955.
1940-1946
Anniversary Speed Graphic (3.25x4.25 and 4x5")
No grey metal exposed, satin black with chrome trim.
Wartime model: no chrome. Bed and Body track rails linked,
allowing focusing of wide angle lens w/in body.
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Solid wire frame viewfinder.
1939-1946
Miniature Speed Graphic (1st small 2.25x3.25" model)
1928-1939
``Pre-Anniversary'' Speed Graphic (3.25x4.25, 4x5, 5x7)
4x5 - wire hoop viewfinder has curved top
1912-1927
``Top Handle'' Speed Graphic
3.25x4.25, 4x5, 3.25x5.5, 5x7
=========================================================================
WHERE TO GET A SPEED GRAPHIC?
Since we are talking about 30-50 year old equipment, you can't buy one
at your local K-Mart. The best way to find a Speed Graphic is to
purchase a copy of Shutterbug Magazine and peruse the ads, or visit
your local camera flea market.
Recent prices vary widely from $300 and up for a beat Speed Graphic to
$150 for a Crown Graphic in great shape with Kodak 127mm f4.7 lens,
filters, 11 normal 4x5 film holders; 1 4x5 film pack adaptor, flash,
bulbs, and case.
* Similar cameras by other manufacturers
---------------------------------------The Toyo 45a Field Camera ($1550) and Horseman 45FA Camera ($2700)
are perhaps the closest current production cameras and could be
compared to the Super Graphic. The Toyo weighs in at 6+ pounds,
while the Horseman (at 3.75 pounds) is set up to be handheld.
There are other 4x5 Field Cameras, but they are more of the classic
wood box tradition, and are generally not constructed so as to be
suitable for hand-holding.
=========================================================================
LENS BUYING GUIDE
Lenses for a 4x5" are specialized. You can group view camera lenses
into 4 broad categories:
1. General Purpose lenses - for work 4'-infinity - mostly older lenses
these are usually of the "tessar" type and can be fairly fast (f/4.5)
2. Symmetrical (wide field) lenses - useful for closeup work and
landscape
3. Extreme Wide Angle lenses
4. Special effects lenses
(Telephoto / Soft focus)
The major American view camera lens manufacturers are Kodak, Wollensak
(OEM supplier for Graflex), and Ilex. Bausch and Lomb was a
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manufacturer in the pre-war period. Other common manufacturers are
Carl Zeiss Jena, Schneider-Kreuznach and Meyer-Goerz-Optik.
---------------------------------------------------------------------1. General Purpose lenses - for work 4'-infinity - mostly older lenses
these are usually of the "tessar" type and can be fairly fast (f/4.5)
General Purpose Lenses: mostly Tessar type, 4 elements, 3 groups
Manufacturer Lens Brand Shutter
Typical Focal Lengths
------------ ------------------------------------------Kodak Ektar
Supermatic
127, 152
Schneider
Xenar
Syncho Compur
127, 135, 150, 180
Graflex
Optar
Graphex
135, 162, 210
Graflex
Optar
Synchro Compur 135
Wollensak Raptar
Rapax
127, 135, 162, 190, 210
Ilex Acutar
(various)
165
Rodenstock
Ysarex
Prontor
127
Schneider
Zeiss
Xenotar
Planar
Synchro Compur
Synchro Compur
135
135
Kodak, Schneider, Wollensak made lenses of approximately the same
focal length. Thus there are equivalent choices in a given focal
length between a Ektar, Xenar or Optar.
Most Graflex Optars are made by Wollensak, but later (post 1965) Optars
are manufactured by Rodenstock.
These lenses are 3 group/4 element "Tessar" type lenses with a 55
degree circle. The Ektars were probably the best all around quality,
with Xenars next, and Raptars and Acutars third. They are fairly close
if in good repair and not mistreated.
The Polaroid 110,110A and 110B roll-film cameras can often be found
very inexpensively. They are fitted either with a Rodenstock Ysarex
127/4.5 or Wollensak Rapter 127/4.5.
In discussing the various post WWII coated lenses mention should also be
given to German suppliers. Due to manufacturing, supply, and legal
problems, there were relatively few post-war Zeiss Tessars made.
NON TESSAR TYPE GENERAL PURPOSE LENSES
Non Tessar type - usually 3/5 type - post war lenses of superb quality
include the Voigtlander Heliars and Apo-Lanthars, the Schneider Xenotar
and the Zeiss Planar. However, they are extremely expensive for a lens
with a 50-degree image circle.
------------------------------------------------------------------------2. Symmetrical (wide field) lenses - useful for closeup work and
landscape
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General Purpose Lenses: 4-element/4-group, 6-element/2-group, etc.
Manufacturer Lens Brand
------------ -----------Kodak W.F.Ektar
Kodak
Ektar
Schneider
Symmar
Schneider Angulon
Graflex
Wollensak
Goerz
Goerz
Shutter
------------
Supermatic
80, 100, 135
Supermatic
203
Syncho Compur
100, 135, 150, 180, 210
Synchro Compur
90, 120
Optar W.A
Raptar W.A.
Graphex
Rapax
90
90
Dagor (f6.8)
Super Dagor (f8)
Focal Length (mm)
Focal Length (inches)
Typical Focal Lengths
---------------------
5",6",6.5",7",8.25",to 14"
3 5/8", 4 3/8", 6.5"
90
3.5
100
4
127
5
135 150
5.25 6
180
7
203
8
210
8.25
Notes : Schneider Symmar
Symmars (coated, post-WWII) come in 100, 135, 150, 180 and 210, all
in Syncho Compurs. Even though these are "convertible", they are poor
when used that way. Later 'Symmar S's from the 70s, more expensive,
have even better coating and wider circle of illumination, but are much
more expensive. However the Symmars are still excellent lenses.
Notes : Kodak WF Ektars
The two Kodak WF Ektars need to be stopped down considerably to equal
in sharpness to the General Purpose Tessar lenses mentioned the the first
section when used as wide-angle lenses. They are less even in illumination
across the same field of view in comparision to a Symmar.
Sharper at wide apertures than the 90mm Angulon, etc. The 135mm WF Ektar
was reccomended for General Purpose use on 4x5 monorail view cameras..
Notes : 90mm Wollensak W/A, Graflex
The Graflex W/A Optar, really a Wollensak Raptar W/A is another
older wide-angle lens. Acceptibly sharp when stopped down, f/6.8
is for focusing only. Use at f/11-32. Of similar design to WF Ektar.
Notes : Kodak Ektar 203mm
The Kodak Ektar, 203mm/f7.7, has a 50 degree angle of coverage. It
is a very old 4-element air-spaced design and has remarkable sharpness
from infinity to close up. Being slow, f/7.7, it is fairly small and
light. Sharpest wide-open.
Notes : Dagor/Angulon
The Dagor and the Schneider Angulon are true symmetricals (f6.8) but
can cover over 70 degrees at f22 and 80 degrees at f45. They are of
six-element, two-group construction. With so few air-glass interfaces
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they are resistant to flare - uncoated Dagors will be acceptible.
------------------------------------------------------------------------3. Extreme Wide Angle lenses
Schneider Super Angulon
90mm
90mm
65mm
f/8
f/5.6
f/8
Rodenstock Grandagon
Zeiss Biogon
These lenses are much more expensive than any lens in either the General
Purpose or Symmetrical category sections. This is especially ture for the
Biogons which are magnificent but totally out of sight in terms of $.
------------------------------------------------------------------------4. Special effects lenses
These long focal length lenses are not ususally hand-held.
4a. Telephoto
Graflex Tele-Optar
Graflex Tele-Optar
270mm f6.5 (Graflex-1000, 1/1000 shutter)
380mm (15") f/5.6 (barrel)
250mm (10") f/5.6 (barrel)
The lenses list are only a small selection of what is available.
Telephoto lenses have a small image circle and use proportionally
less bellows draw than their focal length suggests. The only way
to get 380mm of lens onto a Speed Graphic.
Generally this type of lens does not really allow for movements on
a 4x5. But this issue of what lenses for what purposes on a 4x5 is a
much broader issue not really appropriate to go into furhter in this FAQ
4b. Soft Focus
Rodenstock Imagon
---------------------------------------------------------------------A used 'Speed
Purpose lens.
lenses (127mm
allow the use
Graphic' will typically be found fitted with a General
The Kodak Ektar or Graflex Optar are common. These vintage
Ektar, 135mm Optar ) do not have sufficient coverage to
of movements when focused at infinity.
Beware : Sharpness falls off much faster than illumination.
When checking out an older shutter note that there are separate springs
for slow(<1/30), medium and high speeds (over 1/250). Check all speeds
and exercise the shutter. If you desire to use a flash, be sure to
check for flash synchronization. 'X' mode is for electronic flashes,
while 'M' mode is for flash bulbs, there may be other synchronization
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positions on the switch. Many camera repair shops can clean and
check shutters for accuracy.
Lens Storage
-----------It is generally recommended that lenses be stored set to their lowest
speeds, or 'T' (when available), as this leaves the springs in an
uncompressed state.
=========================================================================
FOCAL LENGTH EQUIVALECE
Focal Lengths as given are nearly equivalent, and may represent
available lenses.
Film Size
Image Format
Film Type
-----------Fisheye
Ex. Wide Angle
35mm
24x36mm
roll
----18mm
120
56x68mm
roll
-----37mm
20mm
24mm
28mm
2"x3"
"
sheet
---------
35mm
40mm
50mm
65mm
85mm
110mm
127mm
150mm
65mm
75mm
100mm
---------
100mm
135mm
210mm
250mm
202mm
-----
65mm
---90mm
100mm
127mm
135mm
152mm
203mm
250mm
270mm
----380mm
250mm
500mm
500mm
-----
---------
---------
50mm
65mm
---47mm
53mm
Moderate Wide Angle
Normal
Moderate Telephoto
Medium Telephoto
Long Telephoto
4"x5"
"
sheet
---------
75mm
(3-1/2")
(4")
(5")
(5-1/4")
(6")
(8")
(10")
(15")
=========================================================================
=========================================================================
CAMERA MOVEMENTS HOW MUCH IS ENOUGH? IT DEPENDS
The 'Speed Graphic' not really a view camera, you can't tie it up
into a pretzel. Depending on the sort of Photography one is interested
in, this may or may not be limiting. The rigidity of the Graphics make
them very useful for high-speed, wide-aperture shooting (the sort of
shot where extreme depth of field is not important). If you are
interested in a 4x5" to pursue photography suitable for 35mm or 2-1/4"
equipment, the motions are an extra, not an essential. There are other
large format photographers who disagree, their personal vision requires
the use of considerable amounts of perspective control.
file:///C|/faq.html (144 of 555) [7/19/2002 3:46:26 AM]
To utilize movements, the photographer must use a lens that has
ample reserve covering power. In the vintage lens field, the
135mm WF Ektar, the 120mm Angulon, or the longish 203mm f/7.7 Ektar
are possibilities.
=========================================================================
Features:
Focusing Back
The pop-open focusing back can usually be removed from the holder by
two clips on the side. This exposes the ground glass retaining clips.
The preferable set-up is to have a fresnel lens as with out it the
image when viewed will get darker as you one views from the center out
to the corners.
Always remember to watch the corners !
If you have a fresnel lens (circular grid on the glass), and the
corners are darker than the center, then you may have adjusted the
camera in such a way that the lens is not covering the area of the
film plane. Many of the standard 'Graflex' lens cover the area of
a 4"x5" sheet, but not much more. Wide angle and wide field lenses
should be clearly marked with WA or WF, indicating they have a greater
coverage area than the diameter of the lens.
Also remember to switch from preview to shutter mode, and stop down the
lens as necessary before pulling the dark slide.
Depending on lighting, you may find a magnifier and dark cloth or
light coat handy (to block out light while focusing on the screen).
=========================================================================
Features:
Infinity Stops
The infinity stops are small tabs which fold over and are located
within the rails, held in place by two extremely small screws. By
folding over the tabs, the lens can pass by the Infinity Stop, which
allows one to use multiple infinity stops, one for each different focal
length lens.
With the rails adjusted to the rear of the bed, and the lens focused on
infinity, you may set the infinity stops for each particular lens.
=========================================================================
Features:
Focusing Scales
Are attached to a moving portion of the sliding rails, and to a fixed
portion of the bed, in front of the lens. The scales, depending on the
lens, will generally have alignment marks for intervals from 6 to 25 feet,
as well as 50, 100 and Infinity.
=========================================================================
Features:
Viewfinders
Cheesey Viewfinder:
Parallax adjustable, with various templates
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for different lenses. Subject too small to see
details while viewing.
Hoop Viewfinder:
Parallax adjustable, allows viewing of the
subject while taking pictures.
Kalart Rangefinders:
Side (steel) or Top (plastic) rangefinder which
is connected to the moving rails, see below.
=========================================================================
Speed Graphics: The Focal Plane Shutter
In a real Speed Graphic the focal plane shutter is the only part that
might be trouble, but is reliable and there are shops dedicated to
fixing them.
Because of the Speed Graphic's focal plane shutter, is slightly heavier
than the similar Crown Graphic, also the depth required for a focal
plane shutter may preclude the user of certain very-wide-angle lens
(below 80mm), where a Crown Graphic may be able to use a 65mm WA lens.
The focal plane shutters operate as a curtain with different sized
openings, and can be set to two speeds with three different openings,
producing speeds of 1/30, 1/60, 1/125, 1/250, 1/500, and 1/1000. Most
lenses with internal shutters will have speeds up to 1/400 or 1/500,
while the Graflex-1000 goes to 1/1000 seconds, there are some some
older ones only go as high as 1/200.
Be careful to know when the curtain is open and closed, as mis-use of
the focal plane shutter will keep film from being exposed (if you're
using a lens shutter), or leaving the curtain open (such as for focusing)
will fog film, if exposed to it.
An advantage of having a focal plane shutter is that you can also use
barrel lenses (w/o a shutter). A 15" (380mm) Graflex Optar Telephoto,
in a barrel mount is much less expensive (~$90) than the equivalent in
a shutter, which seem to go for $250-300. Also, many vintage (1920-30's)
soft focus portrait lenses are only available in barrel.
Use of a slow speed focal plane shutter should produce noticeable
"lean" when you pan to follow moving objects.
Are the large focal plane shutters accurate ?
I checked mine out. 1/1000 sec is dead on. Your average modern SLR
it is probably no more accurate.
=========================================================================
Features:
Kalart Side Mounted Range Finder
[Up to 1955]
Side mounted Kalart rangefinders without interchangeable cams, can be
adjusted for a particular lens, if the proper (tedious) procedure is
followed.
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Operation: The two images in the Kalart are the same color. The split
portion shows up as a center spot. This may become more apparent if
you place a colored piece of gel in front of one of the openings to the
Kalart. [If the half silver mirror is abraised or otherwise lost
silvering, this image may be very faint.] In general bring the split
image into alignment, and if the camera is in focus through-out the
scale, then the rangefinder is cammed or adjusted to the lens.
Here are some instructions for adjusting the Kalart.
-------------------------------------------------------------------ADJUSTING THE KALART RANGEFINDER
The following 4 steps are to be followed in adjusting the Kalart
Rangefinder
1.
2.
3.
4.
Check focus of lens at infinity - if necessary re-adjust infinity stops
Set Rangefinder for infinity
Adjust Rangefinder for 15ft
Adjust Rangefinder for 4ft.
1. Checking Focus of Lens at infinity
The 1st step in synchronizing the RF is to establish the correct
infinity position for the lens - if necessary relocating the camera
infinity stops.
Use a tall building, chimney, etc. at least 1/2 mile away as a
target.
Note: on Pacemaker Graphic (incl. Century) cameras - the track must be
racked forwards to bring the image into focus at infinity.
2. Setting RF for infinity
1st remove the cover over the RF, exposing the innards.
In the event the RF is out of adjustment re-set it as follows:
the infinity adjustment is made by turning the eccentric screw attacked
to the rear of the right runner of the camera track. (this is where the
long lever from the RF on the inside of the bed contacts the focusing
track). You can use a dime to turn this screw. (the screw becomes
visible when the track is raked very far forwards).
3. Adjusting 15ft.
Focus the camera on something approximately 15ft away. use a magnifier
to make absolutely certain of the sharpness of the image. to adjust,
adjust the rear scale (loosen screw which protrudes through a slot
immediately above the words "to loosen
<- -". this is a left-hand
thread!! move the indicator on the rear scale. then tighten.
Repeat the infinity check! (this may take several iterations)
file:///C|/faq.html (147 of 555) [7/19/2002 3:46:26 AM]
4. Adjusting 4ft.
Focus the camera to approx. 4ft. to adjust loosen the two screws which
hold the indexed slider on the front of the rangefinder and slide
the indicator to adjust. retighten screws.
Repeat the infinity check! and 15ft.
Approx. points of adjustment
CAMERA
2x3
LENS
Short Scale (Front)
101mm Optar
9.5
105mm Tessar
10.5
4 3/8"
13.0
105mm f/3.7 Ektar 13.5
CAMERA
4x5
Long Scale (Rear)
LENS
Long Scale (Rear)
127mm Ektar
135mm Tessar
15.0
152mm Ektar
17.0
2
2
2
2
Short Scale (Front)
13.0
3
3.5
5
TOP
Rear scale pointer
--------| \
|
| \
|
| o \ |
|
|
: o
|
# to
1
: loosen2
:
#
|
o
|
#
|
o
| \#
| \|
|
---------
<- 1/2 silvered mirror, screw to adjust align
coincidence
<- screw to loosen rear scale
<- front scale numbers
<- front scale slider
<- screw to loosen front slider
<- screw to loosen front slider
<- prism
=========================================================================
Features:
Kalart Top Mounted Range Finder
[1955 and later]
Featuring interchangeable cams and Parallax Correction.
The cams are tricky to locate and are set up for specific lenses (a
caveat if your camera has a mismatched cam).
=========================================================================
Features:
Graflok Back
[1949 and later]
The 'Graflok Back' is a feature which IS desirable, and is a relatively
'late' enhancement to the Graphic line of camera. These have the
removable focus panel and locks to hold various filmbacks.
file:///C|/faq.html (148 of 555) [7/19/2002 3:46:26 AM]
=========================================================================
Accessories:
Graphic ``Riteway'' Film Holders
Back Type:
Standard
Standard 2 sheet film holders.
[Used: ~$10. each]
=========================================================================
Accessories:
Grafmatic Film Holders
(4x5 model: Cat. 1268)
Back Type:
Standard
The Grafmatic holder (not to be confused with the Graphic Pack Film
holders), will hold size sheets of film in one container. The sheets
are held in individual steel widgets referred to as 'septums'. As of
early 1994, the going prices were advertised as high as $80-$120, but
many individuals report sale prices less than that for holders in good
condition.
It is reported they made Grafmatic's for the older Graphics, which
have a slot instead of ridges for a light-trap on the film-plane side,
buyer beware. Also, watch out for bent film holders, and don't force
the septums in or out. Try practicing loading and unloading in the light,
with spent film or developed sheets to get the hang of it.
They aren't difficult to use, but there are some subtleties in the
loading.
Once you put a negative up front, and pull the slide it will be set
to take the photo 'cause when you put the slide back it, it will be
behind the front one, and then it drops to the back. Thus, if you
prepare the Grafmatic for use, and then decide to re-frame or whatever,
the unexposed negative is still up front. Leave the holder in the
camera and cycle through the septums, back to the one you were on except
don't pull the darkslide on it. That way it's back on top, but not exposed.
=========================================================================
Accessories:
Graphic Film Pack Adapter
(Cat. 1234)
Back Type:
Graflok
4"x5" 16 Exposure Pack Film (Tri-X, etc.) is no longer available.
Operation and packaging seem similar to a Polaroid Pack Film back.
=========================================================================
Accessories:
Roll Film Backs
Back Type:
Graflok (usually)
There were 3 negative sizes, RH-8 (2.25" sq), RH-10 (2.25x2.75") and
RH-8 (2.25x3.25") and holders were made for 2.25x3.25,3.25x4.25 and
4x5" cameras with either Graflock or Graflex backs. Early film
holders, with the knob wind do not hold modern film flat, it bowes
approx. 3/32" towards the film - blowing focus at shallow f/stops.
It seems that lever wind units have the rollers and the knob wind
version do not.
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A conversation with WD Service about this revealed that there were no
roller types made for 3x4. The problem may be subtle, hard to deduce
at first because you figure it was just field curvature or some
aberration.
It also seems that there's a slight overall difference in the film
plane between my non-roller and roller versions (at least sometimes) but they measure the same. May be an artifact of the same problem.
Also, Horseman has current production Graflok roll-film holders, while
Calument sells non-Graflok roll film holders.
=========================================================================
Accessories:
Polaroid Back
Back Type:
Standard
Three flavors exist.
405 for 3.25x4.25 pack film
550 for 4x5" pack film
545i for 4x5" sheet film (ABS plastic, lighter, supposedly improved)
(545) for 4x5" sheet film (steel/brass, black enamel)
An advantage of the 545(i) sheet film holders are that they allow you
to choose any film for any shot, and not be stuck with the same film for
a full pack (8 or 10 shots). Useful if you're shooting 100 then 400,
and want to use the same speed test Polaroid. Ditto for color vs. B&W.
=========================================================================
Accessories:
Miscellaneous
Cases, either civilian or military (O.D. Green).
Ex. 10"x14"x20", velvet lined
Flashes, either civilian (chrome) or military (matt black).
Cat.
2747
2749
2712
2773
Graflex 7 in Reflector (large lamp socket for #11 or #22 bulbs)
Graflex 5 in Reflector (small lamp socket -to large lamp socket
right angle converter, for #B5 bulbs)
Graflex Side Lighting Unit (large lamp socket)
Graflex Synchronizer Battery Case (3 D-Cells)
Filter Kits:
Series VI filter kit (filter holder, Y, G, R, sky, lens shade, in
leather case).
=========================================================================
Parts:
As of 1993, Speed Graphic Western Division sold their stock of parts
to Midwest Photo Exchange (614-261-1264, fax 614-261-1637)
Midwest: Graphic Lens boards (for 4x5)
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$12 + $4 shipping
(prices subject change)
=========================================================================
Books:
``The Pacemaker Graphics (Speed Graphic and Crown Graphic "45" "34" "23")
Instruction and Reference Manual''
42 pages, GRAFLEX, Inc., Rochester, NY 10/47
``The All-American Cameras: a review of GRAFLEX(r)'', Paine, Richard P.
78 Pages (used as a source of the historical information up top, as
well as notes on the development of the Graphics)
``Grafmatic Film Holder Instruction Manual''
6 pages, GRAFLEX, Rochester, NY
``Graphic Graflex Photography'' Morgan and Morgan (1940's through 60's)
(200+ pages). An excellent guide to commercial photography with the
Graphic and Graflex Cameras used as the tools of the trade.
Graflex Factory Repair manual, ~60 pages, details body repair (not
lenses).
=========================================================================
Useful accessories:
Multiple Sheet film holders
Light Meter & Notebook
Lens Shade/Lens Filter Holder
Cable Release for long exposures
Dark cloth / light jacket / etc. to keep out light while focusing
Lupe/Magnifier for checking focus
A Polaroid Back (545/545i sheet holder)
Recommendations:
- Do your own processing & darkroom work.
- Use Polaroids to while learning, and then check framing, exposure,
corners, etc.
- Some say to shoot chromes instead of negs and let them be
their own proofs. You can make prints from the ones you like.
================================================================================
Note 23.02
-< Physical Development Process >-------------------------------------------------------------------------------PHYSICAL DEVELOPMENT PROCESS
Physical development is of interest for two reasons, at least, as it gives an
additional tool for the study of the latent image and as it produces images of
unusually fine grain under the best conditions.
file:///C|/faq.html (151 of 555) [7/19/2002 3:46:26 AM]
Physical development may be carried out after fixation, thus proving that the
latent image is of quite different nature than the silver halide itself. The
following steps may yield successful results if performed before fixation:
1. Treat with potassium iodide bath
2. Rinse
3. Development in Silver-Salt bearing physical developer
4. Fixation
5.Washing and Drying.
For step 1.
POTASSIUM IODIDE BATH
Potassium Iodide
Sodium Sulphite(anhydrous)
Water to make
10g
25g
1 litre
Treat a negative in this bath for 20-30 minutes, rinse and immadiately proceed
to develop in a developer made up as described below:
For Step 3. STOCK SILVER SOLUTION #24
Sodium Thiosulfate (crystals)
Sodium Sulphite (anhydrous)
Silver Nitrate (crystals)
Water to make
160g
60g
16g
1 litre
For use add 1 part stock silver solution to 4 parts of water and add reducing
agent as described below.
To make up this stock silver solution dissolve the sodium sulphite in 300cc of
water, then dissolve the silver nitrate in 100cc of water and then add it to
the sulphite solution stirring until the white curdy precipitate dissolves.
Dilute the whole to 950cc with water and then add the thiosulfate and stir
until a completely clear solution is obtained. Add water to bring volume to 1
litre. Filter through cotton and store in a brown bottle. Solution is fairly
stable and keeps well.
At the time of use of the developer, for each litre of diluted solution add
17 grams of Amidol (Metol), or for each 15 oz. of diluted solution add 12 gr of
Amidol, and stir until dissolved. The Amidol should not be added to the
solution more than 10 minutes before development is to commence.
With tray development 35 min. to 1 hour development time has been recommended
at 68 degrees. Metal containers for the developer should not be used. Glass or
plastic is much preferred.
This special silver bearing developer can be used for physical devlopment
after fixation if that is what is being attempted. Greatly increased exposures
are required over those needed with ordinary chemical development. Fixation
should be carried out in the dark, with rather neutral or alkaline hypo. Use of
acid fixers destroys the latent image by bleaching the weak silver image and use
of physical development may not be successful to "rescue" a negative fixed by
mistake before development.
file:///C|/faq.html (152 of 555) [7/19/2002 3:46:26 AM]
From: Handbook of Photography, by Henney and Dudley, 1939, McGraw-Hill Co.
================================================================================
Note 23.03
-< Electronic Flash Circuit - fundamental >-------------------------------------------------------------------------------... so you want to build your own flash equipment...
It is probably cheaper to buy ready made than trying to build from scratch.
Also safer. If you want to get a general idea how basic electronic flashes
are put together (as well as some fundamental info on operating parameters)
I suggest you try to get a copy of Harold "Doc" Edgerton's book: Electronic
Flash, Strobe. Softcover copy is available from the MIT Press in Cambridge,
MA. for about $15
If you insist on building a basic unit and can handle the safety aspects of
such circuits ... here's a VERY basic circuit:
10-20 ohm
.---^V^V----+------------+----------------------.
|
|
|
|
+ 450 v
| 300uf
> 2 MegOhm
.-.
__|__
| 450V
< .047 uf
.------|-|
___
=====
.-----+--||--------. #
| |
/ | \
|
|
>
| #
| |
|
|
|
< 2 MegOhm
# #
|_|
|
|
|
|
| |
|
\-----------+------|---+-+------------+-+-------'
|
|
Step-Up (Trigger)
|
|
Transformer
V
V
camera sync contacts
Xenon
Flashtube
The potential "power" in a circuit like this is given in Joules (watt.sec) by:
C x V^2
J = ---------2
(Capacitance in f times voltage squared)
DISCLAIMER: THIS CIRCUIT IS INPUTTED TO THE BEST OF MY KNOWLEDGE AS CORRECT.
NO RESPONSIBILITY WILL BE ASSUMED BY ME FOR ERRORS OR INJURY RESULTING FROM
MESSING ABOUT WITH HIGH VOLATGE CAPACITORS, OR ANY INFORMATION GIVEN ABOVE.
*
* * * * *
\/\/\/\/\/\/
Andrew Davidhazy, RIT, High Speed Photography Lab.
|
|
IN%"[email protected]"
fax 716-475-5804
_________/
\_____________________________________________________
================================================================================
Note 23.04
-< DX demystified and controlled >-------------------------------------------------------------------------------> Is there another way to fool my automatic camera's DX code sensing system?
There is a way to override a camera with automatic DX coding: Recode the
cassette yourself. I posted this quite some time ago, but I guess there are a
file:///C|/faq.html (153 of 555) [7/19/2002 3:46:26 AM]
lot of new people on the net.
Here is the key to the DX code:
________________________
|
|
|
|_
|________________________| |
|12 |11 |10 | 9 | 8 | 7 | |
|___|___|___|___|___|____|_|
| 6 | 5 | 4 | 3 | 2 | 1 |
|___|___|___|___|___|____|
|________________________|
ISO
SPEED
SENSING AREA
2
3
4
5
6
25
32
40
50
64
80
100
125
160
200
250
320
400
500
640
800
1000
1250
1600
2000
2500
3200
4000
5000
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
NUMBER OF
EXPOSURES
SENSING AREA
8
9
10
(non-std)
12
20
24
36
48
60
72
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
file:///C|/faq.html (154 of 555) [7/19/2002 3:46:26 AM]
EXPOSURE
RANGE
SENSING AREA
11
12
+- 1/2
+- 1
+2, -1
+3, -1
X
X
X
X
NOTE: An "X" under the sensing area indicates an electrically
conductive area. A "-" under the sensing area indicates an
electrically insulated area. Areas 1 and 7 are always conductive.
Use electrical tape to insulate; use copper or aluminum tape to
make conductive areas. Remember that cameras might depend on
conductivity between conductive areas because the cassette is made
of metal.
________________________________________________________________
There is another way to approach the task: I recently rolled some bulk
Vericolor 400 and Ilford XP-1 for a friend with a Point & Shoot camera.
There were 27 short rolls of each film and I didn't feel like putting
foil tape on each cassette. Since each of these films is ISO 400 and
my friend wasn't going to shoot anything else in the near future, I
decided to recode the CAMERA. Examining the cavity where the cassette
goes, I found contacts for areas 1, 2, 3 and 4 only. Of course, area
1 is always conductive, leaving only three areas for ISO setting.
Looking at the ISO table, we see that this camera is not able to
differentiate between the ISO's between multiples of 25; (ISO 80, 64
and 50 will all set to 50, ISO 160, 125 and 100 will all set to 100,
etc). This is probably just fine for negative film, but may not be
accurate enough for slide film (ISO 64 would be set to 50).
Anyway, I put conductive copper tape (sticky side up) between areas
1 and 4, insulating areas 2 and 3, and then covering over that with
insulating tape. I told my friend that as long as he was shooting my
bulk loaded cassettes, everything would be OK. If he wanted to shoot
something else, then remove the tapes. The first couple of rolls look
OK, so I guess this approach works. Those of you with non-override
cameras might consider this approach.
A couple of years ago, one of the photo magazines had an article on
ways to fool your P&S camera. Does anyone remember the magazine and the
month?
PS:
I'm glad my camera is pre-DX.
Ron Speirs, Evans & Sutherland Computer Corp., Salt Lake City, UT
================================================================================
Note 23.05
-< Photo Discussion Groups on the Internet >-------------------------------------------------------------------------------this note, 23.05, updated 08-15-95
file:///C|/faq.html (155 of 555) [7/19/2002 3:46:26 AM]
several photo related lists w/subscription instructions
If you would like to engage in discussions about photography and imaging
you might consider subscribing to an e-mail discussion group. Several of
these lists are mentioned below.
Just follow instructions and you will
receive further information when each list accepts your "subscription".
Andy Davidhazy, [email protected], School of Photographic Arts and Sciences, RIT
=============================================================================
To subscribe to PhotoForum (Internet) send the one line message below to:
[email protected]
Leave the SUBJ: line blank
in body of message write only the following material and no more:
SUBSCRIBE PHOTOFORUM "your real name here"
where is says: "your real name here" substitute in your real name.
general photo, emphasis on photo/imaging education + professional practice
www: http://www.rit.edu/~andpph/photoforum.html
=============================================================================
To subscribe to Photo-3d send the one line message shown below to
[email protected]
Leave the SUBJ: line blank
in body of message write only the following material and no more:
SUBSCRIBE PHOTO-3d "your real name here"
where is says: "your real name here" substitute in your real name.
discussion about stereo and 3D photos - not computer generated images
www:
=============================================================================
To subscribe to Photo-L send the one line message shown below to
[email protected]
Leave the SUBJ: line blank
in body of message write only the following material and no more:
SUBSCRIBE PHOTO-L "your real name here"
where is says: "your real name here" substitute in your real name.
general photography from basic to advanced, equipment, travel, aesthetics
=============================================================================
To subscribe to a Spanish language Photography mailing list:
Interesados inscribirse con el propietario de la lista Rosalio Vera a:
[email protected] (ROSALIO VERA)
Este es un grupo de interes (Mailing List) de topicos relacionados con
la fotografia en todos sus niveles, exclusivamente en habla hispana.
www:
================================================================================
To subscribe to the Panoramic Imaging Email Discussion List send e-mail to:
[email protected]
In the message body write the following only:
SUBSCRIBE PANORAMA
Dedicated to all aspects of Panoramic Imaging from traditional film based
cameras to digital imaging and the use of Apple's QuickTime VR.
===============================================================================
To subscribe to the PhotoArt Discussion List send e-mail to:
[email protected]
In the message body write the following only:
SUBSCRIBE PHOTOART (insert your full e-mail address)
A list for discussion of photography as an art form and a vehicle for
file:///C|/faq.html (156 of 555) [7/19/2002 3:46:26 AM]
theoretical discourse.
www: http://redgum.bendigo.latrobe.edu.au/~mclennan/PhotoArt/PhotoArt.html
===============================================================================
To subscribe to the Leica users list send the one line message shown below to:
[email protected]
in body of message write only the following material and no more:
SUBSCRIBE leica-users
leica cameras and leica photographic practice
=============================================================================
To subscribe to the Minolta-list send the one line message shown below to
[email protected]
Leave the SUBJ: line blank
in body of message write only the following material and no more:
SUBSCRIBE Minolta-L "your real name here"
where is says: "your real name here" substitute your real name.
minolta cameras and minolta cameras practice
www:
=============================================================================
To subscribe to Canon EOS list send the one line message shown below to:
[email protected]
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file:///C|/faq.html (157 of 555) [7/19/2002 3:46:26 AM]
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a list dealing with anything that relates to the stock photography industry.
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then send the message and that is all there is to it.
underwater photography mailing list - all aspects of this photo specialty
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emphasis on photo history, related items also welcome esp. w/historic twist
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file:///C|/faq.html (158 of 555) [7/19/2002 3:46:26 AM]
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list for discussion of all aspects of large format photography meaning 4x5
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file:///C|/faq.html (159 of 555) [7/19/2002 3:46:26 AM]
===============================================================================
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Devoted to high speed photography in its myriad of forms and applications
===============================================================================
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A list for people who have old photographs and don't know what to do with
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===============================================================================
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This list would be particularly interesting image orinted librarians
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The Kodak Photo CD on the Web list deals with the use of Photo CD images
the Web, based on announcements at the 4th International Web Conference
===============================================================================
================================================================================
Note 23.06
-< Sprayable/Brushable Emulsion Source >-------------------------------------------------------------------------------> I want to put a picture on ceramic-ware. Is there an emulsion that can
be sprayed or brushed onto this material?
The Rockland Colloid Corporation
PO Box 376
Pierpoint Avenue
Piermont, NY 10968
ph 914-359-5559
fax 914-365-0712
The URL for Rockland Colloid is:
e-mail: [email protected]
http://infoweb.net/rockaloid/
makes a sprayable/brushable emulsion
Andy
> ... MORE on Liquid Light and related materials.
A little while back we had some discussion about liquid light and I
mentioned a new book in the UK and promised to find details.
Tonight I went to an opening at the Photographers' Gallery in London - one
gallery of work by Martin Parr and the other by Jerome Liebling. One great
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photographer and one great hype artist. I say this sincerely, not to
belittle the achievement! Possibly more on this another time (and probably
in another place.) Anyway there I was introduced to (ALMOST GETTING TO THE
POINT) Melanie Manchot who is working with these emulsions (and has a show
coming up next week at Watershed Gallery) and who has some illustrations
in the book. Which jogged my memory - hence this post. She also told me
that the publication - orginally down for last Feb now seemed likely to be
in November 1995.
Book details: Silver Gelatin, Martin Reed & Sarah Jones, pub Working Books
(Working Books Ltd, Freepost TK 1827, Richmond Surrey, TW9 1BR Tel 0181 332
0746, Fax 0181 332 9300 - you'll need to add the UK code from abroad of
course.)
More information: Materials available in the UK, said to be superior to
Liquid Light, are made by Kentmere and marketed under various names.
Probably most widely available is Tetenal Work B&W Photo Emulsion.
Silverprint (12b Valentine Place, London, SE1 8QH - 0171 620 0844) have a
range of three emulsions, SE1 (same as the Tetenal), SE2 and SE3. SE1 is a
normal contrast bromide neutral tone high silver emulsion. It is about 5
times as fast as Liquid Light. SE2 is a high contrast version. SE3 is a
chlorobromide emulsion giving warm tones in suitable developers; it is
trickier to use and beginners are advised to start with SE1.
This info is from an article by Martin Reed of Silverprint in p22-37 of Ag
Photographic Vol 6, 1994 ISSN1352-3023 (Also from Woarking Books Ltd).
This seems to cover most things and is well illustrated (including 2
pictures by Melanie) and seems to show quite a range of print colours and
also work on supports including glass and a tea towel.
Peter Marshall [email protected]
================================================================================
Note 23.07
-< Guide Numbers - what are they? >-------------------------------------------------------------------------------> What does the guide number on a flash mean? If it says 50/ISO 100 or
> something, what does that tell me?
The flash guide number is a "device" that allows you to compute an appropriate
f# for a particular subject distance given a particular film speed. It works
like this:
guide number
required f# = ------------------distance from flash
to subject
The guide number of a particular flash is generally given for a full-power
discharge and is associated with a particular film speed. It is sometimes
given both in feet and in meters.
The guide number is given also assuming certain subject characteristics. This
usually means an "average" subject with photography taking place in a small
room with light colored walls. It generally also assumes you will be lighting
your subject from the "front", ie: not side lighting or backlighting.
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Assuming you have a flash with a guide number of 80 with ISO 100 film you will
note that the guide number is 110 with 200 speed film and 160 with 400 speed.
In practice, assuming standard subject located at 10 feet, it works like this:
80
f#? = -------10 feet
f# = 8
If you had film that was twice as fast you would expect a one stop decrease in
aperture. (See below how GNs for other than the film speed given by the flash
maker are determined) So, with same flash as above but using 200 speed film:
110
f#? = -------10 feet
f# = 11
If you move twice as close with your flash again using 100 speed film:
80
f#? = ------5 feet
f# = 16
This is an illustration of the "inverse square" law (colloquialism) that would
indicate that if you decrease the distance between a point source and a screen
to one half the original distance the light level increases fourfold.
In the
above example it means you can close the aperture two stops from the original.
> If I were to set up two Nikon SB-25 flash units to work in synch (on camera),
> what effect would that have on effective guide number ? It seems to me
> (intuition only) that you would have double the effective output power....
This is quite right. As long as the two flash units are near each other you
have effectively doubled the amount of light falling on your subject
consequently you gain a full stop by simply using two units side-by-side.
So, as far as guide number is concerned you would take the initial guide number
with one unit and multiply it by 1.414 (the square root of 2) and you end up
with the new guide number.
To gain two stops you would need four units. For three eight units, etc.
The new guide number will be the guide number of a single flash mutiplied by
the square root of the number of available identical flashes.
> Is there a formula to determine what the guide number would be with any film
> assuming that I know what it is with some other film speed?
Yes. The relationship is determined as follows:
\
\
Unknown GN is equal to Known GN muliplied by
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\
/---------------/ New Film Speed
/
---------------
\/
Base Film Speed
where Known GN is asociated with Base (or Given) Film Speed and Unknown GN is
GN with film speed for which it is desired to find the GN.
for example: assume you are given a flash with a GN of 80 with 200 speed film.
what is the GN with 400 speed film? and with 50 speed film?
Unknown GN = 80 times the sq. root of
400/200
or
Unknown GN = 80 times the sq. root of
50/200
or
1.414 x 80 = 110
.5
x 80 =
40
>I know the meaning of the "Guide Number" (translated from French ;-)) of a
>flash which is the distance of efficiency of a flash with a 100ISO film at
>f-1 (correct me if I'm wrong). But I if I use a 200 ISO film and if I'm at
>f-5.6 how far can my flash be efficient ???
Actually any flash has a particular guide number at full power or at a given
power level setting if it has such capability. This guide number is also a
function of, and varies with, the speed of the film that you will be using.
What the guide number allows you to do is to determine what f stop you should
be using to expose the film and this will depend on subject distance. Dividing
the distance from the flash to the subject will indicate the f number you
should be setting on your lens.
In your mail you are incorrect in assuming that something about f:1. Guide
number is a function of the power of the flash and the film. For example, if
your flash has a guide number of 24 (in meters) with 100 speed film, and your
subject is at 3 meters from the camera then you would set your f number to f:8
and if the subject distance is 10 meters than at f:2.4 (f:2 would be safer) and
if at 1 meter then the f number would be about f:22.
If you used 200 speed film with the same flash then the guide number would be
33 and all the above f numbers would be one f number away from the above ones
.... effectively requiring only 1/2 the light that was needed before because you
have film that is twice as fast.
If you wanted to find out the farthest distance that your subject can be with
any given flash then simply divide the guide number by your largest available
aperture (f:2 or f:1.4 or such) and the number you get is the distance the
subject can theoretically be at. With 200 speed film the distance will be 1.4
times farther than with 100 speed film because light falls off inverseley with
the distance squared. So, if you increase distance 1.4 times then 1.4 x 1.4
equals 2 and this means that at that new distance the light is 1/2 as strong as
it was at the previous location.
Note 24.01
-< Harris Shutter - making and using it! >-------------------------------------------------------------------------------HARRIS SHUTTER FOR COLOR MOTION EFFECTS
A Harris Shutter introduces color in areas of a subject that move during the
exposure while those that remain stationary are reproduced with proper color.
Unusual images can be produced especially of waterfalls, ocean surf, and
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similar subjects where a white object is in motion. This special effect
technique is named after Robert S. Harris who was with Kodak's Photo
Infortmation Department. He is an RIT grad!
In the "Here's how book of Photography" vol 2, the process is described in
detail. The filters used are the Wratten 25, 61 and 38A. His suggestion for
exposure is to give one stop more exposure than would be required without a
filter for each filter used if you use them manually and expose sequentially.
The Harris Shutter is more commonly associated with the "drop" version of the
shutter described below. Hopefully with Kodak's indulgence, I will exerpt some
notes from the aforementioned book.
There are two ways to accomplish the desired effect through RGB filters.
Number One is with the camera on a tripod and by sequential axposure through
each of the three filters, Wratten 25, 61 and 38A. These should be available
from photo dealers and they are commonly available in 75mm squares for about
$10 each. Glass equivalents are made by companies like Tiffen, Hoya, etc but
these tend to cost more. Possibly cellophane filters by Roscoe may also be
suitable.
Basically you place the camera which must have the capability of multiple
exposing the film (without the film moving beteen exposure) on a very firm
tripod. Then meter the scene and expose sequentially through each filter giving
one stop more exposure through each than that which was recommended by the
meter.
The reason that more exposure is required is that these filters remove some
of the RGB light that each layer would normally be exposed to if the exposure
were without filter. Bracketing is recommended.
Recommended film is COLOR NEGATIVE because some color correction is possible at
enlargement stage. Color slide films, however, can also be used.
Number Two is to make a guillotine type affair that falls in front of the lens
possibly in a slot of some kind that is attached to the lens. The affair looks
sort of like this:
----------|
|
|
|
| opaque
|
|
|
|
|
||---------||
||
||
|| red
||
||
||
||---------||
||
||
|| green ||
||
||
||_________||
||
||
file:///C|/faq.html (164 of 555) [7/19/2002 3:46:26 AM]
To make action pictures:
This mask falls in front of lens while
the shutter of the camera is held open
typically the "shutter" is built into a long
|| blue
||
||
||
||_________||
|
|
|
|
|
|
/----\
|
| \_ ____/
||
| opaque
|
|
|
|
|
|
|
|
| _|____
|
|
| /
|_____|
|
|
------------
hollow box fitted to front of lens and
held onto a lens shade or filter holder
for exposure Harris suggested that you use the aperture that would be required
for an exposure time of 1/30 second. Also, bracket!
My personal feeling is that the exposure recommendations given in the book
re: Harris shutter or exposures "sound" optimistic and that a bit of
experimentation is probably in order. One way to "balance" exposures is to
locate the "darkest" filter (and this will vary depending on the light source)
and then use ND filters on the other ones to bring them in line with the film
sensitivity characteristics for each of the other two layers.
You could attemt to determine the proper ND filter to use behind each color
filter by metering through each filter, identifying the one that needs the
least compensation and then add ND value as you meter through the other two
until the readings for these are the same as the reading through your
"benchmark" filter.
If you do this I don't foresee a problem other than an esoteric one having to
do with realizing that the spectral sensitivity pattern of the meter's cell vs.
the spectral characteristics of the color film will influence the process.
Actually a bit of fiddling with exposure will produce variations that may be
more interesting than "dead-on" exposure.
Another interesting suggestion is to use this filter in front of a projector
projecting the slide made with this filter. The image will appear to move as
the various colored areas of the filter are placed in front of the projector
lens.
Another suggestion is to only use complemetary filters. A yellow with a blue
would basically be an ND filter yet parts of the scene that move would be
colored. Interesting also.
I think that at one time someone manufactured a Harris shutter but if it was
available commercially it was so long ago that I have forgotten who sold it.
On the other hand, this might be a nice sideline for some enterprising person
to undertake. Some light plywood, a lens adapter system and the filters ...
I can see it now... retiring to exotic places, palm trees on island beaches,
hmmmm... :-)
file:///C|/faq.html (165 of 555) [7/19/2002 3:46:26 AM]
Andy
@rit
================================================================================
Note 24.02
-< Electronic Visualization of Color Negatives >-------------------------------------------------------------------------------VIDEO PREVISUALIZATION OF COLOR NEGATIVES
I have been previewing and visualizing negatives by the simple
expedient of using a videocamera having a POS/NEG mode. The macro mode
ought to let you get close (and if not then use diopter lenses) to not
only fill frame but even crop. Switching on the NEG mode reverses
subject tone and color. Just what is needed!
Use of a bluish filter helps to allow the white balance of the camera
to reach proper color balance condition. These images can, of course,
be videotaped. Color printing is another, more time consuming but
possibly more rewarding, matter.
Andy
@RIT
================================================================================
Note 24.03
-< Film Codes Demystified >-------------------------------------------------------------------------------> ..... often people refer to film by the code name. Does somebody have a
> list of those codes with the normal names next to it? I know TMX is Tmax 100
> by Kodak but what is Fuji RVP VRP PDP or whatever cryptic code they have?
A quick list of the most popular ones starting with Kodak products:
B&WTMXTMYTMZPXTXVPTP-
Tmax 100
Tmax 400
Tmax 3200
Plus-X 125
Tri-X 400(
Verichrome
Technicial
(PXP-120 propack version)
(TXP-120 propack version)
Pan (120 only)
Pan
Color
VPSVPHVPLEPNEPPEPXLPPLPZEPREPYEPDEPL-
Vericolor III 160
Vericolor 400
Vericolor II type L(tungsten)
Ektachrome 100
Ektachrome 100 Plus
Ektachrome 100X (warm bal.)
Lumiere 100
Lumiere 100X (warm bal.)
Ektachrome 64 daylight
Ektachrome 64 tungsten
Ektachrome 200
Ektachrome 400x (warm bal.)
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EPJ- Ekatchrome 320 tungsten
Comon Fuji ones are:
CSNHGNSPNLPRVPRFPRDPRHPRSPRTP-
Fuji Reala 100
Fujicolor 400
Fujicolor 160 (short exp.)
Fujicolor 160 (long exp.)
Velvia 50 slide film
Fujichrome 50 (RF- amateur version)
Fujichrome 100 (RD- amateur version)
Fujichrome 400 (RH- amateur version)
Fujichrome 1600 (only 35mm)
Fujichrome ? tungsten
From: Brian G Segal - [email protected]
and
From: [email protected]
================================================================================
Note 24.04
-< Obsolete Film Processing >-------------------------------------------------------------------------------> I recently purchased an old Kodak #2 folding Autographic Brownie containing
> a partly-exposed roll of Kodacolor-X. I'd like to get the roll developed and
> printed. Unfortunately, it is Process C-22, a process obsolete for many
> years. Is there a lab that will still process this film?
One lab that touts itself as the _ULTIMATE_ special process lab and one which
is equipped to process C-22 films, as well as E-4 (for Ektachrome Infrared!),
E-3, E-2, K-11, K-12, EFKE, ORWO,as well as various others is Rocky Mountain
Film Lab. They are at 560 Geneva Street, Aurora, CO, 80010 phone: 303 364-6444.
They even seem to handle Nimslo/Nishika films.
The price to process, print and return ship Kodacolor-X is (was) $25 a roll
and the in-house time is from 3-4 months they say. They suggest you send your
film, cheque and name/address in a padded mailer.
On envelope also write Dept: __________
<----- place the film type here.
They have a website at: http://www.rockymountainfilm.com/
I have no connection with this lab. They have processed my films. Good job.
hope this helps,
Andy
================================================================================
Note 24.05
-< Canon A1 control contacts described >-------------------------------------------------------------------------------> Does anyone have precise details on the contacts on the base of the Canon
> A1, in particular, how do you trigger the shutter with them.
Let me label the contacts 1-4 like this, with 1 being the indented one:
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_________________________________________
/ O 1
___ \
| o 2 Contacts
/
\|
| o 3
screw |===||
| o 4
\___/|
\_________________________________________/
|
|
|__________|
If you short 1 and 4, this is the same as pressing the shutter release
half way, i.e. activates meter etc. Shorting 1 and 3 and 4, fires shutter.
Probably Relay contacts, not solid state devices, should be used as switches.
From: Tristram Scott, [email protected]
University of Canterbury, Christchurch, New Zealand
================================================================================
Note 24.06
-< Copyright - basic information >-------------------------------------------------------------------------------COPYRIGHT - a simply informal primer
by Erica Wissolik, Library of Congress
I'll try to answer a few of the questions re: copyrights. There are several
books out there that explain the basics of the law but the axiom is - Once its
created, its copyrighted. So, Yes, you can declare your work copyrighted just
by saying so. Registering a copyright is for litigation purposes only.
1. What can be copyrighted?
The act divides works into 7 broad
graphic and sculptural works.
categories, # 5 being pictorial,
2. Rights and protection mandated by the law?
A copyright is a property right. There are 5 general rights a) right to reproduce the work
b) right to prepare derivative works based on the work
c) right to distribute to the public copies of the work
d) the right to perfom publicly a copyrighted literary, dramatic, musical
or other audio-visual work
e) right to display publicly a copyrighted literary, ..., pictorial,
graphic or sculptural work, incl. the individual images in a motion
picture or other audio-visual work.
****Each of these 5 parts can be further subdivided. eg. an owner can license
someone to reproduce a work for him/her but limit the license time, quantity or
manner of reproduction.
3) Does one have to file formal paperwork for something that one wishes to
declare copyrighted? Or register in some way with a federal bureau?
No, you do not have to file formal paperwork in order to register your
copyright. As stated above, once you have created your work, it is
automatically yours and you can legally place the copyright symbols (there are
several ways to do this) next to your name on the work. However, formally
registering your work is an extra measure of protection in a court of law. It
file:///C|/faq.html (168 of 555) [7/19/2002 3:46:26 AM]
provides tangible evidence that the work is yours and has been since the date
of creation and you'll save yourself a bundle in legal fees. The forms are
fairly tedious but the cost is minimal. However, there is something called "a
poor man's copyright". If you have lots to copyright, that minimal fee can add
up. If cost is a concern to you, this will provide almost the same amount of
legal protection without the cost. Simply, seal a copy of the work in an
envelope and send it to yourself. File it away and do not open it. The
postmarked, unsealed letter is evidence that you created the work by a given
date.
OK - moving on... while you do not have to formally register your copyright,
you do have to DEPOSIT the work in the Library of Congress. The Copyright Act
imposes the requirement on the owner to deposit 2 copies of all works in its
collection (easy way to get stuff without paying for it - oops, I didn't say
that). This deposit requirement is NOT a precondition to copyright protection.
They are 2 separate conditions. Within 3 months of declaring copyright notice,
you must make the deposit. This mandatory deposit provision applies only when
the work is published - that is placed on sale or distributed. If the deposit
is not made - things get expensive. The Registrar of Copyrights comes after you
and demands the deposit. The first demand doesn't cost you anything. If you
ignore it and he comes after you a 2nd time, there is a $250 fine plus the
retail cost of copies. Ignore that, the 3rd time and any repeated negligence
carries a $2500 fine!
***Note - If you do formally register your copyright with the LC, the deposits
filed with the registration will fulfill all deposit requirements.
The only "federal bureau" concerned with copyrights is the Library of Congress.
At this point, I could go into a long explanation of the Berne Convention, the
agreement between several countries that allows your works to be protected
outside of the US, but I'll spare you all that unless someone asks.
BTW If you want more, everything that anyone could possibly want to know about
copyrights and the law is available on LC MARVEL (LC's Machine Assisted
Realization of the Virtual Electronic Library). I'm not sure how much the
outside world knows about MARVEL yet but if you want to contact the design
team, they're at - [email protected]
Its the greatest resource. You will find all of the Copyright info conveniently
located on the menu under "Copyright". Follow the menu and you eventually come
to the sections that are "photograph" specific. Also on the menu is the option
to search current copyright files. You can find out who holds what copyrights
on everything - Beatles songs, photos, artwork, the scripts for Beverly Hills
90210, etc. However, the online searches are limited to the last 20 years (I
can't remember the exact date). The rest of the files exist only on 3x5 index
cards in file cabinets 2 floors above me.
You will also be able to find a copy of The Berne Convention, mentioned above.
It will be listed in MARVEL under government info resources/international govt
info/treaties & internatl covenants, between the UN Charter and a treaty on
hazardous waste. Hopefully this will all be clear once you are able, if you
choose to do so, access MARVEL. I'm not a computer wiz. Working here I can
access this stuff with a mouse and icons but the MARVEL is currently available
to you on Internet and uses the Gopher software from the Univ. of Minnesota.
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So go ahead and put that little "c" next to your name and rest assured that
your work belongs to you. Hope some of this helps. Let me know if I can do
anything else.
That's all,
Erica Wissolik
Congressional Research Service
Library of Congress
[email protected]
================================================================================
Note 24.07
-< Bellows Sources >-------------------------------------------------------------------------------Need replacement bellows? Here is a suggestion:
Replacement bellows, with an original frame, are done by Universal Bellows,
25 Hanse Ave., Freeport, N.Y. USA 11520 (516) 378-1264 or fax 767-7387.
They should be able to do anything you want, but you must supply FIRST both
ends of the frame. If that doensn't work, why not call Ron Wisner, and ask
who builds his bellows? Wisner Mfg is at 800-848-0448 (Massachusetts).
best of luck. -mike
From: [email protected] (Michael Biedul)
Organization: MIND LINK! - British Columbia, Canada
------------------------------------------------------------------------I recall that right here in Rochester there also is a manufacturer of
custom bellows. I looked them up in phone book and here is the scoop:
Turner Bellows
526 Child Street
Rochester, NY 14606
ph 235-4456
fx 235-4593
andy, [email protected]
================================================================================
Note 24.08
-< Cross Processing Benchmark >-------------------------------------------------------------------------------> I have been experimenting with cross processed C-41 & E6 films and chemistry.
> I have found the results of my 1st three attempts a bit dissapointing.
I see a lot of cross-processed film, and we have established a "standard"
to which all others are compared. The standard is Vericolor HC exposed at
an EI of 32 and pushed three stops in E-6. This gives a good skin tone
and reasonable contrast and shadow detail. Most of the Ektars (now Royal
Gold) produce high contrast, monochrome-like results. The Fuji's don't
seem to cross process as well as the Kodak films, but it really depends
on the look you are after.
file:///C|/faq.html (170 of 555) [7/19/2002 3:46:26 AM]
Rand Molnar
Brooks Institute
<[email protected]>
================================================================================
Note 24.09
-< Postcard Printer Pointer >-------------------------------------------------------------------------------Making Photographs into Postcards
One of the major U.S. postcard printers is Lawson Mardon Post Card,
and they deal with professional photographers. In fact they will use
photographers as "reps," where you get a commission from any postcard
orders you sell to clients.
I've used them twice and the quality (of color from transparencies)
was excellent both times. The cost is good, too: 500 4 x 6 cards
at a cost to you of $225, or at a cost to your client of $320.
The "Mirror-Krome" division of Lawson Mardon can be reached at
1-800-347-2723.
jay
[email protected]
================================================================================
Note 24.10
-< Hyperfocal Distances for short 35mm lenses >-------------------------------------------------------------------------------> If anyone has a chart showing the hyperfocal distances for the commonly
> used 35mm prime lenses (e.g. below). Perhaps it could be posted to the
> net as I am sure it would be of general interest.
> Lenses include 20mm, 24mm, 28mm, 35mm, 50mm, 85mm, 100mm, 135mm, 200mm etc
I reprint a chart from Outdoor Photographer, Mar. 1993 found in the Tech
Tips column of George Lepp (he reprinted it from the Gallery 412
newsletter). The chart is set for a 0.001 'inch circle of confusion' - in
other words it is for sharp foregrounds. There are many possible charts of
hyperfocal distances so I only take responsibility for typos, not the
information given. These values are in feet.
Lens
f/8
20mm
7
24mm
f/11
f/16
f/22
f/32
5
3.5
2.5
1.7
10
7
5
3.5
2.5
28mm
13
10
7
5
4
35mm
20
15
10
8
5
50mm
42
30
21
15
10
For those who are unsure what the hyperfocal distance is, it is the point
at which to set your lens to ensure 'optimal' focus from the closest
possible point to infinity. The hyperfocal distance is twice the closest
optimal focal point ie. in the chart under the 28mm lens the closest point
file:///C|/faq.html (171 of 555) [7/19/2002 3:46:26 AM]
of optimal focus at f/32 will be 2 feet.
From: [email protected] (Jon Bertsch)
================================================================================
Note 24.11
-< Photo Manufacturers and Distributors list >-------------------------------------------------------------------------------Photographic Company Listings as compiled by:
Adrian Chew :) [email protected]
-------------------------------------------------Acme-Lite/Promark
1731 Carmen Dr.
Elk Grove Village, IL 60007
(708) 593-7400
Aetna Optix, Inc.
44 Alabama Ave.
Island Park, NY 11558
(516) 889-8570
Agfa Corporation
100 Challenger Rd.
Ridgefield Park, NJ
(201) 440-2500
07660
Aluminum Case Co.
3333 W. 48th Pl.
Chicago, IL 60632
(312) 247-4611
Ambico, Inc.
2950 Lake Emma Rd.
Lake Mary, FL 32746
(407) 333-8900
Argraph Corp.
111 Asia Place
Carlstadt, NJ 07072
(201) 939-7722
Arkay (Division of Omega/Arkay)
P.O.B. 2078
191 Shaeffer Ave.
Westminster, MD 21158
(410) 857-6353
B & H Photo-Video
119 W. 17th Street
New York, NY 10011
(800) 221-5743
Beattie Systems, Inc.
P.O.B. 3142
Cleveland, TN 37311
(800) 251-6333
Beseler (Charles) Co.
1600 Lower Rd.
Linden, NJ 07036
(908) 862-7999
Birns & Sawyer, Inc.
1026 N. Highland Ave.
Hollywood, CA 90038
(213) 466-8211
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Bogen Photo Corp.
P.O.B. 506
Ramsey, NJ 07446-0506
(201) 818-9500
Brightscreen
1905 Beech Cove Dr.
Cleveland, TN 37312
(800) 235-2451
Bronica: See GMI Photographic Inc.
Buhl Optical Co.
1009 Beech Ave.
Pittsburgh, PA 15233
(800) 245-4574
Calumet Photographic, Inc.
890 Supreme Dr.
Bensenville, IL 60106
(800) CALUMET
Canon U.S.A. Inc.
1 Canon Plaza
Lake Success, NY 11042
(516)
Chimera
1812 Valtec Lane
Boulder, CO 80301
(800) 424-4075
Chinon America Inc.
1065 Bristol Rd.
Mountainside, NJ 07092-1248
(908) 654-0404
Cima America, Inc.
5 Marine St.
Huntington, NY 11743
(516) 385-1757
Coast Manufacturing Co.
200 Corporate Blvd. South
Yonkers, NY 10701
(914) 376-1500,
Colenta America Corp.
347 Evelyn St.
Paramus, NJ 07652
(201) 265-5670
Cullman/Titan: See GMI Photographic Inc.
Da-Lite Screen Co., Inc.
P.O.B. 137
Warsaw, IN 46580
(219) 267-8101
Deardorff & Sons, Inc.
312 S. Peoria St.
Chicago, IL 60607
(312) 829-5655
Dimco-Gray Co.
8200 S. Suburban Rd.
Centerville, OH 45459
(513) 433-7600
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Domke Photo Resources
21 Jet View Dr.
Rochester, NY 14624
(716) 328-7800
Dyna-Lite Inc.
311-319 Long Ave.
Hillside, NJ 07205
(908) 687-8880
Eastman Kodak Co.
343 State St.
Rochester, NY 14650-0811
(716) 724-6000
Edmund Scientific Co.
101 E. Gloucester Pike
Barrington, NJ 08007
(609) 573-6234
Elmo Mfg. Corp.
70 New Hyde Park Rd.
New Hyde Park, NY 11040
(516) 775-3200
Exakta Camera Co.
979 North Ocean Ave.
Patchogue, NY 11772
(516) 331-5500
Falcon Safety Products, Inc.
25 Chubb Way
P.O.B. 1299
Somerville, NJ 08876-1299
(908) 707-4900
Fiberbilt Cases
601 W. 26th St.
New York, NY 10001
(212) 675-5820
Fuji Photo Film
U.S.A. Inc.
555 Taxter Rd.
Elmsford, NY 10523
(914) 789-8100
Globuscope Cameras
44 W. 24th St.
New York, NY 10010
(212) 243-1008
GMI Photographic Inc.
P.O. Drawer U
125 Schmitt Blvd.
Farmingdale, NY 11735
(516) 752-0006
H.P. Marketing Corp.
16 Chapin Rd.
Pine Brook, NJ 07058
(201) 808-9010
Hasselblad (Victor) Inc.
10 Madison Rd.
Fairfield, NJ 07004
(201) 227-7320
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Heitz (Karl), Inc.
P.O.B. 427
Woodside, NY 11377
(718) 565-0004
Helix
310 S. Racine
Chicago, IL 60607
(312) 421-6000
Hervic Corporation
16516 Arminta
P.O.B. 7800
Van Nuys, CA 91409
(818) 781-1692
Horseman: See GMI Photographic Inc.
Ilford Photo
70 W. Century Rd.
Paramus, NJ 07653
(201) 265-6000
Jobo Fototechnic, Inc.
251 Jackson Plaza
Ann Arbor, MI 48103
(313) 995-4192
JVC Company of America
41 Slater Dr.
Elmwood Park, NJ 07407
(201) 794-3900
Kaiser Corp.
3555 N. Prospect St.
Colorado Springs, CO
(719) 636-3864
Kalt Corp.
P.O.B. 511
Santa Monica, CA
80907
90406
(213) 305-1166
Konica U.S.A., Inc.
440 Sylvan Ave.
Englewood Cliffs, NJ 07632
(201) 568-3100
Leica Camera Inc.
156 Ludlow Ave.
Northvale, NJ 07647
(201) 767-7500
Light Impressions
439 Monroe Ave.
Rochester, NY 14603
(716) 271-8960
Lumedyne, Inc.
6010 Wall St.
Port Richey, FL 34668
(813) 847-5394
Mamiya America Corp.
8 Westchester Plaza
Elmsford, NY 10523
(914) 347-3300
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Minolta Corp.
101 Williams Dr.
Ramsey, NJ 07446
(201) 825-4000
Nikon Inc.
1300 Walt Whitman Rd.
Melville, NY 11747
(516) 547-4355
Norman Enterprises, Inc.
2601 Empire Ave.
Burbank, CA 91504
(818) 843-6811
Novatron of Dallas, Inc.
8230 Moberly Lane
Dallas, TX 75227
(800) 527-1595
Olympus America Inc.
145 Crossways Park West
Woodbury, NY 11797-2087
(516) 364-3000
Omega
P.O.B. 2078
191 Shaeffer Ave.
Westminster, MD 21158
(410) 857-6353
Oriental Photo Distributing Co.
3701 W. Moore Ave.
Santa Ana, CA 92704
(714) 432-7070
Pentax Corp.
35 Inverness Dr. East
Englewood, CO 80112
(800) 877-0155
Polaroid Corp.
575 Technology Square
Cambridge, MA 02139
(617) 577-2000
Quantum Instruments, Inc.
1075 Stewart Ave.
Garden City, NY 11530
(516) 222-0611
QuickSet International, Inc.
3650 Woodhead Dr.
Northbrook, IL 60062-1895
(708) 498-0700
Ricoh Corp.
180 Passaic Ave.
Fairfield, NJ 07004
(201) 808-3563
Sailwind Photo Systems
1809 Commonwealth Ave.
P.O.B. 9426
Charlotte, NC 28299-9426
(704) 376-1470
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Satter Inc.
4100 Dahlia St.
Denver, CO 80216
(303) 399-7493
Saunders Group
21 Jet View Dr.
Rochester, NY 14624
(716) 328-7800
Schneider Corp. of America
400 Crossways Park Dr.
Woodbury, NY 11797
(516) 496-8500
Seal Products Inc.
550 Spring St.
Naugatuck, CT 06770-9985
(203) 729-5201
Sharp Electronics Corp.
LCD Products Group
Sharp Plaza, Mahwah, NJ 07430-2135
(201) 529-8728
Sigma Corporation of America
15 Fleetwood Court
Ronkonkoma, NY 11779
(516) 585-1144
Sima Products Corp.
8707 N. Skokie Blvd.
Skokie, IL 60677
(708) 679-7462
Sinar Bron
17 Progress St.
Edison, NJ 08820
(908) 754-5800
Slik (Tripods): See Tocad America Inc.
Smith-Victor Sales Corp.
301 N. Colfax St.
Griffith, IN 46319
(219) 924-6136
Sunpak (Flash): See Tocad America Inc.
Tamrac
9240 Jordan Ave.
Chatsworth, CA 91311
(818) 407-9500
Tamron Industries, Inc.
99 Seaview Blvd.
P.O.B. 388
Port Washington, NY 11050
(516) 484-8880
Tenba, Inc.
503 Broadway
New York, NY 10012
(212) 966-1013
Testrite Instrument Co., Inc.
135 Monroe St.
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Newark, NJ
07105
(201) 589-6767
Tiffen Manufacturing Corp.
90 Oser Ave.
Hauppauge, NY 11788
(516) 273-2500
Tocad America Inc.
300 Webro Rd.
Parsippany, NJ 07054
(201) 428-9800
Tokina-Hoya-Kenko
1512 Kona Dr.
Compton, CA 90220
(310) 537-9380
Varta Batteries, Inc.
300 Executive Blvd.
Elmsford, NY 10523
(800) 431-2504
Vivitar Corp.
1280 Rancho Conejo Blvd.
Newbury Park, CA 91320
(805) 498-7008
Vue-All, Inc.
P.O. Drawer 1690
Ocala, FL 34478-1690
(904) 732-3188
Yankee Photo Products
Division of Saranda Corp.
4025 E. Broadway
Phoenix, AZ 85040
(602) 437-8200
Yashica Inc.
100 Randolph Rd.
Somerset, NJ 08875
(908) 560-0060
Note 25.01
-< Daguerreotype Info from 1858 available on-line >-------------------------------------------------------------------------------as seen on PHOTOHST mailing list:
"American Hand Book of Daguerreotype" available online
I have prepared a digital edition of the "American Hand Book of the
Daguerreotype," by S. D. Humphrey, 5th edition, 1858. I have
contributed the ASCII text version (with GIF images of the
illustrations to Project Gutenberg. You can fetch the files via
anonymous FTP from:
mrcnext.cso.uiuc.edu
in directory
/pub/etext/etext94
The files are:
amdag10.zip (or .txt) -- ASCII text
amdgf10.zip
-- GIF files of the illustrations
file:///C|/faq.html (178 of 555) [7/19/2002 3:46:26 AM]
Any comments or suggestions are welcome.
A second text that I have prepared will be one of the October releases.
-Greg Walker
[email protected]
Digital Daguerreian Archive Project -Electronic texts from the dawn of photography.
================================================================================
Note 25.02
-< List of Photo/Imaging Books, Magazines, etc. >-------------------------------------------------------------------------------This is a partial list of magazines, newsletters, and books relating to
photo/imaging being compiled by Jerry Courvoisier of Southern Illinois
University's Photographic Production Technology Department. He is also
trying to keep the list current and asks that if you know of additional
publications you please email the info to him at [email protected]
Books
Larish, John, Digital Photography Pictures of Tomorrow
Micro Publishing Press, Torrance CA 1992
Larish, John, Photo CD - Quality Photos at your Fingertips
Micro Publishing Press, Torrance CA 1993
Adobe Photoshop Classroom in a Book
Adobe Press /Hayden Books
Rich, Jim and Bozek, Sand
Photoshop in Black and White
Peachpit Press Inc. Berkeley CA 1994
Linnea Dayton & Jack Davis
The Photoshop WOW Book
Peachpit Press Inc. Berkeley CA 1993
Weinmann, Elaine and Lourekas, Peter
Photoshop for the Macintosh
Peachpit Press Inc. Berkeley CA 1993
Sally Wiener Grotta/ DanielGrotta
Digital Imaging for Visual Artists
Windcrest/McGraw-Hill 1994
Mark Beach
Graphically Speaking
North Light Books 1992
Biedny, David, Monroy, Bert
The Official Adobe
Photoshop Handbook Bantam Books 1991
Breslow, Norman
Basic Digital Photography
Focal Press 1991
file:///C|/faq.html (179 of 555) [7/19/2002 3:46:26 AM]
McClelland, Deke
Macworld Photoshop 2.5 Bible
IDG Books Worldwide, Inc. 1993
Arlington TX 76012
Adele Droblas Greenberg & Seth Greenberg
Fundamental Photoshop
Osborne McGraw-Hill 1994
Newsletters
Electronic Photography News
EPN Publishing Div.
Photofinishing News Inc.
10915 Bonita Beach Rd.
Bonita Springs, FL 33923
Fractal Design Gallery
P.O. Box 2380
Aptos, CA 95001-9973
Photo/Imaging Education Assocation (PMA)
3000 Picture Place
Jackson, MI 49201
Association of Texas Photography Instructors
P.O. Box 121092
Arlington, TX 76012
Magazines
Photo Imaging In The Year
2000- The Future of the Photo/Imaging Industry,1991
Photo Marketing Association International
3000 Picture Place
Jackson, MI 49201
Omura, Dr. Glenn,
Imaging Technology Trends Transition to a New Industry,1991
Photo Marketing Association International
3000 Picture Place
Jackson, MI 49201
Studio Photography
Div. Of PTN Publishing
445 Broad Hollow Rd
Suite 21
Melville, NY 11747
Photo Lab Management
P.O. Box 1700
Santa Monica, CA 90406-1700
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T.H.E. Journal
(Technological Horizons in Education)
150 EL Camino Real Suite 112
Tustin, CA 92680-9833
PC Graphics and Video
P.O. Box 7708
Riverton, NJ 08077-8708
Publish
Integrated Media Inc.
501 Second St.
San Francisco, CA 94107
PC Magazine
Ziff-Davis Publishing Company
Computer Artist
P.O. Box 2649
Tulsa, OK 74101-9632
Photographic Processing
900 Haddon Ave. Suite 326
Collingswood, NJ 08108-2101
Advanced Imaging
445 Broad Hollow Road
Melville, NY 11747-4722
Photo Electronic Imaging
1090 Executive Way
Des Plains, IL 60018
Photo Marketing
Photo Marketing Association International
3000 Picture Place
Jackson, MI 49201
Minilab Developments
2627 Grimsley Street
Greensboro, NC 27403
Wired
P.O. Box 191826
San Francisco, CA 94119
Photo District News
49 East 21st Street
New York, NY 10010
New Media
Hypermedia Comm. Inc.
901 Mariners Island Blvd.
Suite 365
San Mateo, CA
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Mac User
P.O. Box 52461
Boulder, CO 80321-2461
Mac World
P.O. Box 51666
Boulder, CO 80312-1666
Mac Week
525 Brannan St.
Suite 309
San Francisco, CA 94107
Communication Arts
410 Sherman Ave.
Palo Alto, CA 94306
News Photographer
1446 Conneaut Ave.
Bowling Green, OH 43402
419-372-8308
Step By Step Electronic Design
6000 N. Forest Park Drive
Box 901
Peoria, IL 61656
ART AND DESIGN NEWS
5783 Park Court
P.O. Box 501100
Indianapolis, IN 46250
(317) 849-6110
Industrial Photography
PTN Publishing Co.
Div. Of PTN Publishing
445 Broad Hollow Rd
Melville, NY 11747
Presentations Magazine
Lakewood Publications Inc.
50 S. Ninth St.
Minneapolis, MN 55402
TV Technology
P.O. Box 1214
Falls Church, VA 22041-9808
Inform
Association for Information and Image Management
1100 Wayne Ave. Suite 1100
Silver Spring, MD 20910
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Imaging World
P.O. box 1358
Camden, ME 04843
Silicon Graphics World
P.O. Box 399
Cedar Park, TX 78630-1285
================================================================================
Note 25.03
-< Basic Photo Lesson w/pinhole camera >-------------------------------------------------------------------------------HOW TO MAKE/USE A PINHOLE CAMERA
What follows is offered for public school teachers who may wish to
introduce photography on a basic level in their classrooms. What is
presented is written on a -very basic- level, not to insult anyone's
intelligence, but to be as complete as possible. Further, this is not
intended to be "the last word" on the subject - It's only one approach
among many. For instance, those familiar with graphic arts will
immediately see that Ortho film could be easily substituted as the negative
material.
Yours in teaching,
Carroll Hale
(Chair/Professor - Art) Eastern Kentucky University
[email protected]
-----------------------------CUT HERE-------------------------------------BASIC PHOTOGRAPHY FOR THE
PUBLIC SCHOOL CLASSROOM
(USING THE PINHOLE CAMERA)
The prime goal of this project is to teach the basics of classic
Positive/Negative photographic technique. Secondary goals are to
make the project interesting to students from many grade levels,
keep the need for special materials-equipment-facilities to a
minimum, hold down costs as much as possible, and avoid
technically complicated processes.
To achieve these ends, the photographic process chosen is of
extreme simplicity. However, because the depth of the student's
involvement may be varied from the level of simply making the
exposure, to that of starting with the construction of the camera
and continuing through printing, students of markedly different
photographic sophistication should find the project stimulating.
The process chosen is about 150 years old. It was developed by
the photographic pioneer Henry Fox Talbot. The name he chose for
it, Calotype, means "beautiful picture". The reason Calotype was
chosen for this project is that it is a very simple and
"forgiving" process which requires a minimum of materials and yet
contains all the basic steps of standard photography. In this
process the negative is made on translucent paper rather than a
transparent substrate. The negative is then "contact-printed" on
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a second piece of the same sort of paper. The resulting positive
image is soft by current standards (that is, it's slightly blurred
by the pinhole "lens" and the light scattering properties of the
paper negative). Further, these images cannot readily be enlarged
or reduced. This last shouldn't be a drawback in most public school
classrooms since enlarging equipment would needlessly complicate
the project. The camera used in the project is one of absolute
simplicity, a pinhole type, that may be made for less than a
dollar. The negative-print size is 4"X 5". This is large enough
for the print to be a desirable acquisition on the part of the
student while remaining small enough to keep costs down. Paper
size is modular in the sense that it divides evenly into the 8" X
10" sheet of photo printing paper which is standard and readily
available (you can also buy 4"X 5").
A BRIEF DESCRIPTION OF THE CAMERA:
The camera is a cardboard box of approximately 4"X 5"X 6" outside
dimensions. It is most readily made of black matboard with the
black surface in the interior. If black matboard is not
available, another heavy opaque cardboard (approximately 1/8"
thick) may be used providing the interior is completely
blackened. One 4" X 5" end is covered with a removable cap while
the other has the pinhole centered in it. The removable cap
serves as the negative holder. The pinhole is made in a piece of
aluminum foil and is taped to the inner surface of the box
centered in a cut-out about 1/4" square. (The smaller the
pinhole, the sharper the picture, but the longer the exposure.)
When making the pinhole, press through the foil into a piece of
cardboard then pull the pin straight back to make a clean, round
hole. Check to make sure the edges of the hole are clean and flat
for the sharpest possible image. An opaque flap on the outer
side of the front cap serves as the pinhole's shutter. Cover all
possible light leaks (especially seams and scored edges) with
opaque tape. The cap and the shutter are easily secured by
rubber bands.
I hope the construction is clear from the diagrams below (it's
not too easy doing them in ASCII!)
Cut matboard to the dimensions shown and score on the side
AWAY from the direction of fold.
BASIC BOX (make one)
^
|
6"
|
v
<-19"
-->
-------------------------------I
|
|
|
| I
I
|
|
|
| I
I
|
|
|
| I
I
|
|
|
| I
I
|
|
|
| I
-------------------------------<-4"-> <-5"--> <-4"-> <-5"--><1">
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END CAPS (make two)
Bend the 1"W flaps
back
<6"
->
________
I-I------I-I ^
I |
| I |
I |
5"| I
I |
| I 7"
I |
| I
I_|__4"__|_I |
I------I
v
ASSEMBLE TO LOOK LIKE THIS (below)
_________
/--------/I
_______________
6" /
/II
4" / /----------/ /I
/________/ II
/ /
/ / I
I--------II II
I-I-----------I-I I
FRONT CAP
I
II II
I I
I I I
GLUED-ON
I flap II II
I I
I I I
5"I I--I II II
5"I I
I I I
REAR CAP
I I__I II II
I I
I I I LEFT REMOVABLE
I
II /
I I
I I I
I
II/
I I
I I /
I--------I/
I-I-----------I-I/
4"
6"
FRONT 3/4 VIEW
SIDE 3/4 VIEW
ADDITIONAL CONSTRUCTION DETAILS: Make sure the pinhole is EXACTLY
in the center of the front cap. The flap that covers the pinhole
may be hinged with a piece of tape - a second piece of tape may
be use to make a tab so that the flap can be easily opened. it's
a good idea to blacken the outer surface of the camera, under the
flap and rear cap, to cut-down on light leaks. Also making the
rear cap deeper than 1" helps cut down on light leaks (don't make
the cap too deep or it will act like a piston when it is put on
and will blow-out the foil).
PROCEDURE
THE ELEMENTS OF THE PROCEDURE ARE PROVIDED IN SIMPLE OUTLINE AND
OBVIOUS REQUIREMENTS OF ANY LESSON (E.G. HAVE MATERIALS ON HAND
AND ORGANIZED) ARE LEFT OUT.
I.
CAMERA CONSTRUCTION
The decision as to whether the student is to construct the camera
or him/herself or use one already made can only be made by the
classroom instructor. If one is to be made, a complete
demonstration and close guidance are practical necessities. Four
cameras may be made from a single sheet of matboard. Some matboard
is left over, but little is wasted. Making a camera should take
about one class period if the parts are precut and -IF- all goes well.
II. LOADING THE CAMERA
The camera is loaded under safelight conditions. The safelights
used for this paper must be amber. Three or four sheets of RC II
paper may be cut at a time. The 8" X 10" sheets are easily cut
on a guillotine type paper-cutter into four 4" X 5" pieces per
original sheet. Since the safelights put out little light it is
best to mark the paper cutter ahead of time at the 4" and 5"
marks with tape that strongly contrasts with the cutter board.
Cut all sheets for the project at one time. Remember, each photo
takes at least two sheets, one for the negative and one for the
print. This is probably not a job for young or careless
students. Even under safelight illumination, photo paper will
fog if it is left out for a few minutes. Only a few sheets
should be out to be worked on at any one time. When the paper is
file:///C|/faq.html (185 of 555) [7/19/2002 3:46:26 AM]
not in use it should be stored in a light-tight box.
The cut
sheets are loaded singly into the camera with the shiny surface
facing the pinhole. Place the sheet in the back cap and put the
cap on the camera. Secure it with two rubber bands and make sure
the shutter is closed (taped or held by a rubber band). Check
the area to be sure all light sensitive materials are put away
and turn on the room lights.
III. MAKING THE EXPOSURE
Exposures are made in full/hazy sunlight. The camera is placed on
a solid object that isn't subject to motion. It's a good idea to
hold the camera down with something that weighs a pound or two
if there is any chance it might be moved by wind or whatever
during the exposure. A book works well for this. The shutter is
opened and secured by a rubber band. Thirty seconds are allowed
to elapse and the shutter is closed and secured. THAT'S ALL
THERE IS TO IT! If the camera is joggled accidentally when the
shutter is opened or closed it doesn't matter since the exposure
is so long a second or two of upset is unimportant.
IV. DEVELOPING THE NEGATIVE
Prepare the chemicals as per instructions on the packets for
stock solutions. Stock solutions should be kept in plastic
bottles so that the obvious problems brought on by broken glass
in a dark room can be avoided. The developer (Dektol) is used at
a ratio of one part stock solution to two parts water. The stop
bath and fixer are used in stock solution. Prepare one tray each
of developer, stop bath, fixer and a running water bath. The
trays should be large enough to hold a 4" X 5" sheet easily.
4"X 5" trays will do but are cramped. 5" X 7" trays are better.
The "chemical" trays should be filled to a depth of an inch or
so. Tongs must be used to avoid possible dermatitis. The wash
tray should be at least 8"X 10" since there will usually be
several negatives/prints washing at any one time. A siphon
circulator is a great aid to washing. If one isn't available,
use a tray that has a drain hole or two set about 1/2" below its
edge or the prints will keep washing over the edge of the tray.
What follows is done under SAFELIGHT.
1.
The camera is unloaded
2.
The negative is placed (shiny side up) in the developer for
1 to 2 minutes. It is a good idea to slightly dog ear a
corner the so the tongs will slide under. Agitate the
solution gently at approximately 10 second intervals.
3.
Remove the negative from the developer by one corner and
allow the developer to drain off the diagonally opposite
corner. Place the negative in the stop bath for 5 to 10
seconds. Agitate continuously.
4.
Remove the negative from the stop bath by one corner etc...
Place in the fixer for 2 minutes. If no other light
sensitive materials are out, the remainder of the negative
processing may be done in ordinary room light. Use a 10
second agitation cycle as above.
5.
Remove etc... place in the wash for 5 minutes.
6.
Remove etc.. squeegee both front and back and dry with the
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hair dryer. Dry the front (emulsion) side first. (If the
wet emulsion is allowed to dry in contact with another
surface it will be permanently glued to it.)
YOU NOW HAVE A NEGATIVE.
V.
MAKING THE PRINT
What follows is done under SAFELIGHT.
1.
Place an unexposed sheet of the Rapid RC II paper shiny side
up on a black background. (A piece of matboard is
excellent.) Place the negative face down on the fresh
paper. Make sure the two pieces are evenly aligned. Put a
sheet of clear glass over the paper to hold them in firm
contact with each other.
2.
Expose this "sandwich" to the light from a 15 watt household
bulb in a reflector (clamp-lamp) at a distance of 3 feet for
about 5 seconds. If other wattages are used the time will
vary. Make sure that no other light-sensitive material is
inadvertently fogged during the exposure. If the print is
too light, more exposure is needed. If it is too dark, use
less exposure. This negative may be used to make many prints.
3.
Process the print just as the negative was above (IV. steps
1. through 6.).
VI. CLEAN-UP
Used chemicals should be dumped in an environmentally approved
fashion. Do not return them to the stock solution bottles as
they will weaken the fresh chemicals. If the used chemicals must
be saved, put them in bottles reserved for the purpose and
clearly marked as such. The trays should be rinsed and drained
and left to dry. Any spills should be sponged up and the area
washed with clear water. Store chemicals and paper in a cool,
dry, dark place.
MATERIALS AND EQUIPMENT LIST
DARKROOM:
Photo Printing Paper - Kodak Rapid RC III, "F" surface
Developer, Paper - Kodak Dektol
Stop Bath - Kodak, With Indicator (optional but recommended)
Fixer (Hypo) - Kodak, General Purpose
Running water of potable quality
Jugs, Plastic, 3 ea., (to hold chemicals)
Trays, 3 ea., Plastic, Min. 4" X 5" X 1 1/2"Deep (may be larger)
Tray, 1 ea., Plastic, Min. 8" X 10" X 1 1/2"Deep (may be larger)
Tongs, Photo Print, 2 ea.
Contact printing frame or a Min. 5" X 7" sheet of glass and black
surface to print on
Timing device (watch with seconds display)
Light, 15 watt, in reflector (Clamp-lamp)
Safelights, Amber, Min. 2 ea.
Hairdryer
Squeegee, Photo Print (optional)
Extension Cords, as needed
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CAMERA:
Posterboard, Black, strip 6" X 33"
Glue, White
Tape, Black-Opaque (electrician's tape will do)
Foil, Aluminum, 1/2" square
Straight-edge/Ruler
X-Acto knife
Pin, Ball-Headed Straight, (J. & P. Coats size 20)
Bands, Rubber, 3" or 31/2" X 1/8", 3 ea.
----------------------------END-----------------------------------Date: Fri, 23 Sep 1994 16:00:11 -0400
From: "E. C. HALE" <[email protected]>
Subject: HOW TO MAKE/USE A PINHOLE CAMERA
================================================================================
Note 25.04
-< Tips for use of PhotoFlo >-------------------------------------------------------------------------------> I would like any tips on removing and/or preventing water spots on
> dried negs. Even though I always use photoflow, I have a problem with
> spots from time to time.
The problem could be many things...
1. Check your water source, excess minerals in the water will cause
spots. Try mixing your Photo-Flo with DI, or distilled water and see if
the problem persists.
or...
2. Mix the Photo-Flo a bit weaker than recommended and keep it changed
often. The spots you're seeing may actually be Photo-Flo sludge marks a common ailment when the solution is too strong or too old.
or...
3. Lightly squeegie the film before drying. Sometimes the Photo-Flo
dries before the suds slide off the film and leave marks accordingly.
Also, check your film dryer temperature, rapid drying of the film also
prevents the suds from sliding off the film before drying.
or...
4. Even though this is highly unlikely the problem, and I don't mean to
insult anyone's intelligence, but I have known of students who, until
corrected, thought that they should rinse the film off in water !after!
the Photo-Flo, thus spots.
Hope this helps.
Barry Snidow,
North Lake College
Irving, Texas
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[email protected]
================================================================================
Note 25.05
-< Remote Camera Triggering Discussion >-------------------------------------------------------------------------------Subj:
RE: remote nighttime photography
There are several commercial IR (beam interrupt) and sound detectors available
on the market. A fairly popular one is the Dale Beam. It costs around $500 as
do most of the others.
These devices allow you to set up an invisible beam of IR and when something
interrupts the beam it causes a switch to close thereby tripping a camera
capable of being tripped by the closure of a switch.
To set up the system so that the camera will ONLY fire when the subject is in a
specific location in space an "X" beam set-up must be set up. This can be
arranged by splitting a laser beam (if you don't mind a light spot to possibly
show up on your subject you could use a red, visible, AV laser pointer) with a
beam splitter and using a few mirrors directing each 1/2 beam so that they
recombine on the tripper's sensor but traveling through space in such a manner
that they cross at the desired location.
The sensitivity of the device is adjusted so that when either half of the beam
is broken the sensor's response is still high enough that the switch does not
close. But when both halves are interrupted, bingo, the device trips the
shutter.
This type of synchronizer would be called a "dark" activated synchronizer.
BTW... you could also use a device
"trap" shooting mode. Meaning that
trips. I don't know which specific
colleagues on the list will let us
built into several modern cameras called a
when the subject is in focus the camera
cameras have this feature but I am sure our
know.
If your camera does not have the capability of being fired by the simple
closure of a switch your problems are magnified manyfold. It is also useful to
have a winder or motor drive on the camera. I think some of the simples cameras
to trip with simple switches are Canon and Olympus cameras since they use a
2 mm (or maybe it is 1.5mm0 or subminiature plug available at most electronic
stores (such as Radio Shack). Nikons use "special" connectors but you can
circumvent this with a bit of ingenuity. I have simply slipped short lengths of
household extension wire, after appropriately expanding the plastic, over the
bottom two of the pins if a three connector Nikon plug or over both is a two
pin type and then a simple connection of the stripped ends should cause the
motor to fire the camera. (I can not accept responsibility for damage to pins
or camera due to installation of "improvised" cables).
Anyway, we routinely build such synchronizers in my photoinstrumentation class
with students learning the basic function of the circuit's "building blocks",
making the printed circuit board, buying the components, and assembling the
final product. The cost if they scrounge for surplus parts is around $25. For
this they get a Light, Dark and Sound activated synchronizer with delay
capability and operable also as an intervalometer.
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The electronic basis for the device is a 556 integrated circuit double timer
chip. The output is either independent SCR's, independent relays or a single
relay switchable from timer one to timer two.
We also use this device to make milk splash photographs ala Doc Edgerton. (sort
of as illustrated in my signature file appended below) There are I am sure more
refined designs and designs built on digital rather than analog circuitry but
for us the 556 works well.
If anyone would like to have a copy of the circuit, as well as other circuits
that friends have sent me,I would be happy to mail you a copy if you send me
private mail and include your snail mail.
Andy
o o 0 0 o
o
\/\/\/\/\/\/
Andrew Davidhazy, at RIT's Imaging and Photo Tech Dept
|
|
[email protected]
High Speed Photography Lab
_______/
\_________________________________________________________
The Dale Beam can be obtained from the manufacturer,
Protech, Inc.
703-941-9100
You can also obtain a similar device called the Shutter Beam from:
Woods Electronics
c/o Steve Yankey
619-486-0806
================================================================================
Note 25.06
-< More on Polarizing Filters! >------------------------------------------------------------------------------->I would like to know how a circular polarizing filter works.
This is a subject which could really use a chalkboard to
explain.......Or, if you remain confused, try an optics text in a college
bookstore. The description in the first paragraph below might be tough
to visualize, so you might want to skip to the second paragraph.
The first element in a circular polarizer (CP) is a regular polarizer.
So, light entering the CP is first filtered by a polarizer--reducing
reflective glare and all the things a polarizer normally does. The next
element (actually binded to the polarizer) is a "quarter wave plate".
This is made of a material that is birefringent--light polarized one way
has a different index of refraction (and, hence, speed) than light
polarized in the perpendiclar direction. What this does (and what a
blackboard is needed to explain) is take the light which now is
polarized, say, up-down, and convert it to light where the polarization
vector rotates around in a circle with time. I.e. the light comming out
of the CP will be polarized up-down one instant, then polarized 45! off
an instant later, then polarized 90!!off another intstant later and so
on.
file:///C|/faq.html (190 of 555) [7/19/2002 3:46:26 AM]
What does this do? It takes light and filters it into polarized light by
the first element. Then it converts this polarized light into light
which is a combination of two polarizations. Some cameras pick off one
polarization for the light meter and/or autofocus. So, if you had used a
linear polarizer, you could filter out all the light that your meter
would see, so your meter would think it was very dark outside and would
overexpose your image. Or, you might not be able to use your camer's AF
capability.
By using a circular polarizer, you take the linearly
polarized light from the first element and convert it into light which
has both componenets of polarization--just as "natural" light does. This
allows light to pass the filters in front of the meters/AF.
Do you need a circular polarizer? Only if your camera body requires it
for some purpose. I have a Nikon N2020, which a camera store owner was
convinced needed a CP (he was wrong) and an N90 which does need it. Will
it change the look of your pictures? No, unless it is made poorly (the
bonding of the quarter wave plate and gettin all surfaces optically flat
is what makes these things cost more. There is more possibility for
something to be done wrong with them).
From: Matt Carey <[email protected]>
Subject: Re: how does a circular polarizer work?
Organization: UCSD
================================================================================
Note 25.07
-< Kodak 2481 HS Infrared Film Data Sheet >-------------------------------------------------------------------------------Kodak High Speed Infared Film 2481
(Estar Base)
* A high-speed, infared-sensitive black-and-white film on
dimensionally stable .004-inch (0.10nm) Estar Base.
* Sensitive through the visible region of the spectrum and in the
infared to approximately 90nm, with maximum sensitivity from 750nm
to 840nm.
* Used in scientific, medical, biological, industrial and
questioned-document photography.
HANDLING: Handle only in total darkness. No safelight should be
used.
EXPOSURE
FILTERS: For most applications, a filter must be used over the lens
(or light source) to absorb the blue light to which the film is
sensitive. For general photography, a KODAK WRATTEN Filter No. 25
is recommended for this purpose. If only infared is to be recorded,
use a KODAK WRATTEN Filter No. 87, 87C, 88A or 89B or its
equivalent. Under very low light conditions and when infared
rendition is not important, the film can be exposed without a
filter.
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FILM SPEED: Exact speed recommendations are not possible because
the ratio of infared to visible radiation is variable and because
photoelectric meters are calibrated only for visible radiation. Use
a hand-held meter rather than a through-the-lens type.
It is recommended that trial exposures be made to determine proper
exposure for the conditions under which photographs will be made.
Under average conditions, the following speeds can be used as a
basis for determining exposures when meters marked for ASA speeds
or exposure indexes are used.
SPEEDS FOR RECOMMENDED DEVELOPMENT IN KODAK DEVELOPER D-76:
KODAK WRATTEN FILTERS
DAYLIGHT
TUNGSTEN
No. 25, 29, 70, or 89B
50
125
No. 87 or 88A
25
64
No. 87C
10
25
Without a Filter
80
200
FOCUSING: For best definition, take all infared pictures at the
smallest lens opening that conditions permit. If large apertures
must be used and the lens has no auxiliary focusing mark, establish
a focusing correction by photographic focusing tests. A basis for
trial is the extension of the lens by 1/4 of 1 percent of the focal
length of the lens.
DAYLIGHT EXPOSURES: -for subjects in bright or hazy sunlight
(distinct shadows):
EXPOSED THROUGH KODAK WRATTEN FILTER NO. 25
Distant Scenes
Nearby Scenes
1/125 sec at f/11
1/30 sec at f/11
NO FILTER
Distant Scenes
1/125 sec at f/16
PHOTOLAMP EXPOSURE TABLE: For use with a KODAK WRATTEN Filter No.
25 over the camera lens. Use two 500-watt reflector-type photolamps
or two No. 2 photolamps in 12-inch reflectors giving comparable
light output. Place one lamp on each side of the camera at an angle
of 45 degrees to the camera-subject axis.
Lamp-to-Subject Diatance
Lens Opening at 1/30 Sec.
3 feet
f/11
4 1/2 ft
f/8
6 1/2 ft
f/5.6
FLASH EXPOSURE: To obtain the lens opening for electronic flash or
flashbulbs, divide the guide number by the distance in feet from
flash to subject.
ELECTRONIC FLASH GUIDE NUMBERS: Use with a KODAK WRATTEN Filter No.
87 over the camera lens:
Output of Unit
(BCPS or ECPS)
Guide Number for
Distances in Feet
350 500 700 1000 1400 2000 2800 4000 5600 8000
20
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24
30
35
40
50
60
70
85
100
Guide Number for
Distances in Meters
6
7
9
11
12
15
18
24
26
30
PROCESSING PROCEDURE
1. Develop:
Approximate Developing Time (in minutes)
Kodak Dev
Aprox
Contrast
SMALL TANK-(agit at
30-sec intervals)
65F 68F 70F 72F 75F
18.5C 20C 21C 22C 24C
D-76
LARGE TANK*-(agit at
1-min intervals)
65F 68F 70F 72F 75F
18.5C 20C 21C 22C 24C
0.70
13
11
10
9.5
8
14
HC-110
0.80
(Dilution B)
7
6
6
5.5
5
7
D-19 (maximun contrast)
7
6
5.5
5
4
8.5
1.65
12
6.5
11
9
5.5
5
6
10
7.5 6.5
6
5
*Development times of less than 5 minutes in a large tank may
produce poor uniformity and should be avoided.
2. Rinse:
At 65 to 75 F (18.5 to 24 C) with agitation.
Kodak Indicator Stop Bath - 30 seconds.
OR
Kodak Stop Bath SB-5
- 30 seconds.
A running-water rinse can be used if an acid rinse bath is not
available.
3. Fix:
At 65 to 75 F (18.5 to 24 C). Agitate films frequently during
fixing.
Kodak Rapid Fixer
-2 to 4 minutes
OR Kodak Fixer
-5 to 10 minutes
OR Kodak Fixing Bath F-5 -5 to 10 minutes
4. Wash:
For 20 to 30 minutes in running water at 65 to 75 F
C). To minimize drying marks, treat in Kodak Photo-Flo
after washing, or wipe surfaces carefully with a Kodak
Chamois or a soft wet viscose sponge. To save time and
water, use Kodak Hypo Clearing Agent.
5. Dry:
in a dust free place.
STORAGE:
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(18.5 to 24
Solution
Photo
conserve
Keep unexposed film in a refrigerator or freezer at 55 F (13C) or
lower in the original sealed container. If the film is stored in a
refrigerator, remove it four hours before opening the package. If
stored in a freezer, remove it about eight hours before opening. A
sufficient warm-up time before opeing the package is necessary to
prevent condensation of atmospheric moisture on the film.
Keep exposed film at 40 F (4 C). Process the film as soon as
possible after exposure to avoid undesirable changes of the latent
image. If it is necessary to hold exposed but unprocessed film for
several days, it should be resealed and refrigerated. Before
unsealing and processing exposed film that has been stored in a
refrigerator or freezer, follow the moisture prevention and
handling procedures for raw film as described above.
FOR MORE INFORMATION: see the following Kodak Publications
No. M-28, Applied Infared Photography
No. N-1, Medical Infared Photography
No. N-17, Kodak Infared Films
NOTICE!
This film will be replaced if defective in manufacture, labeling or
packaging. Except for such replacement, the sale or any subsequent
handling of this film is without warranty or liability even though
defect, damage or loss is caused by negligence or other fault.
Eastman Kodak Co, Rochester, NY
14650
Kodak, Estar, Wratten, D-76, HC-110, D-19 and Photo-Flo are
trademarks.
Note 26.01
-< Aluminum Frames - where to buy them? >------------------------------------------------------------------------------->some years ago I bought a batch of aluminum frames for a show, now
>I've lost my source file. anyone know of a good cheap, fast source
>for 11 x 14 and 16 x 20 frame pieces?
I use Contemporary Frame Co., Dept O, 346 Scott Swamp Rd, Box 514, Farmington,
CT 06032. For information, call 1-203-677-7787, or to order, call
1-800-243-0386. Their minimum credit card order was $25 the last time I
ordered, which was about a year ago. I don't recall how fast they delivered,
but if they have what you want in stock, I'm sure they will expedite it for a
price. (But then they may cease to be considered 'cheap'.)
The frames I usually get, their style 905 silver ones, cost about $6.61 for a
16x20, and that includes the necessary hardware. Locally, I'd pay $15 or more
for the same thing.
John Snell <[email protected]>
..........................................................................
Try for framing:
Westfall Framing 1-800-874-3164 (FL 800-334-1652)
file:///C|/faq.html (194 of 555) [7/19/2002 3:46:27 AM]
or
United Mfrs
1-800-645-7260 (Lots of supplies for a framer)
They have a nice simple frame for 5.80 (16x20) Hdwre included.
Both take credit cards.
K. Mosley ([email protected])
.............................................................................
Frames can be purchased from American Frame Company - (800)537-0944
Marshall Kragen
[email protected]
..............................................................................
yet another source is:
Light Impressions
439 Monroe Ave.
Rochester NY 14603-0940
1-800-828-6216
FAX 1-800-828-6216
================================================================================
Note 26.02
-< Polarizing and UV filters - Q and A >-------------------------------------------------------------------------------This file contains the answers to frequently asked questions about polarizing
and UV/skylight filters. I saw so many questions about these filters on news,
I thought it wouldn't hurt to make it a FAQ.
If anyone has comments on this faq or useful supplements, please E-mail them to
or
[email protected]
[email protected]
All the information useful to other news-readers will be added to this FAQ,
mentioning the name of the one who sent it to me. You can also E-mail to the
above address if you still have unanswered questions about filters. Should
there still be questions that are frequently asked, I'll add them to this FAQ.
This file may be copied and distributed freely, as long as you keep in intact.
So let me get the credit for the time I spent on it and do not just copy parts
of it, for chances are that I will get questions that are already answered in
this FAQ.
I will try to keep this FAQ in rec.photo.*, posting the new version when this
one is removed from the list.
------------------------------------------------------------------------------* THINGS THAT HAVE CHANGED SINCE THE ORIGINAL FAQ *
file:///C|/faq.html (195 of 555) [7/19/2002 3:46:27 AM]
update september 28, 1994
- The answer to Q2 of the polarizing filters has been replaced by the FAQ on
circular polarizers written by TOM DAVIS ([email protected])
- DAVID JACOBSON ([email protected]) suggested I should go for the
wave theory on light instead of the particles. I tried. He also had some
useful comments I have added to this FAQ, and he pointed out an error in A5
on the polarizers. I was wrong on the amount of light you loose, but it has
been corrected now.
- RICHARD KARASH ([email protected]) also had some comments on the circular
polarizer, but they were already in the circular polarizer FAQ by Tom Davis.
- Via news JEFF SPIRER ([email protected]) and Dr. GROVER LARKINS
([email protected]) also commented on the polarizers, mostly about the
circular vs. linear question, and dr. Larkins commented on my advice of
overexposing film when in doubt of the light. This is corrected. The other
comments on the circular polarizer were already corrected in the circular
polarizer faq by Tom Davis.
update september 29, 1994
- LUCA DE ALFARO ([email protected]) sent in a test about determining if you
really need a circular polarizer. Jeff Spirer sent a comment on this, so I
decided to unite both of them in Q6 and A6 on polarizers.
update october 3, 1994
- JOE CALI ([email protected]) sent in an explanation of the so called
"Brewsters Angle". This is added to the FAQ in Q7 and A7.
update october 4, 1994
- Rev. Dr. PHIL HERRING ([email protected]) pointed out that even if you
use a manual camera, a linear polarizer might disturb your light meter. This
is added to A2 on polarizers
* I want to thank all of them for their contribution to this FAQ. *
------------------------------------------------------------------------------- Polarizing Filters -
Q1: What does a polarizing filter do?
A1: In order to answer this question, you'll first have to know something about
light. Light can be regarded as a flow of particles (called photons), or as
an electromagnetic wave. I'll try to stick to the wave theory. So, light
can be regarded as a waveform, oscillating in an arbitrary direction
perpendicular to its direction of motion. There will be waves oscillating
up/down, oscillating left/right and all that's in between those two.
A polaroid filter only allows to pass the component of the oscillation that
is directed in the polarizing direction of the filter.
file:///C|/faq.html (196 of 555) [7/19/2002 3:46:27 AM]
So only the waves that are oscillating in the polarizing direction can pass
the filter unattenuated. All other waves will attenuate according to the
formula:
Amplitude after polarizing = Amplitude before polarizing * cos (theta),
where theta is the angle between the oscillating direction of the wave and
the polarizing direction of the filter.
The overall effect is blocking out half of the available light, and
'directing' the other half.
Q2: What is the difference between a linear and a circular polarizer?
A2: The main points are:
(1) If you use a standard linear polarizer with cameras that use auto-focus
and/or auto-exposure, you may have problems.
This filter may also cause trouble with manual cameras, if you're using
TTL light measurement. A little dependent on the camera, your meter
might go crazy.
(It is not said you _will_ get problems, only that you might get them.)
(2) A circular polarizer can be used on all cameras, and will work the same
as a linear polarizer with respect to darkening the sky, eliminating
glare, et cetera -- circular polarizers are just more expensive.
A circular polarizer is just a linear polarizer followed by a quarter-wave
plate set at 45 degrees to the axis of polarization.
A quarter-wave plate is made of a material in which light polarized in one
particular direction travels more slowly than light polarized in the
perpendicular direction. A quarter-wave plate is just thick enough that
after passing through it, light polarized in one direction is delayed 90
degrees (or one-quarter wavelength) relative to light polarized in the
other direction.
Since the quarter-wave plate is set at 45 degrees to the polarization, you
can think of the incoming light as having two equal components in the
principal directions of the quarter-wave plate. After passing through the
plate, one component is delayed 90 degrees, and the resulting light is
circularly polarized.
The idea is to use a linear polarizer up front to get rid of some linearly
polarized light you don't want (glare off shiny surfaces, for example, will
have a large linearly polarized component), and then it "stirs up" the
result so you don't have linearly polarized light bouncing around in the
camera.
A problem with linearly polarized light in your camera, for example, is
that when you bounce it off a mirror at (near) Brewster's angle, it may be
(nearly) completely eliminated. If the light meter measures the light
after it bounces off a mirror, the amount of light arriving at the meter
may be drastically different than the amount of light that will arrive at
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the film with no bounce, since the mirror has flipped out of the way.
Of course, a quarter-wave plate is only exactly a quarter wave for one
frequency of light. That frequency is usually chosen to be a yellow in
about the middle of the visible spectrum so that on the average, the light
will be circularly polarized with various degrees of elliptical
polarization mixed in. I suppose if you were photographing something that
was primarily red, or primarily violet, your metering might be slightly
off, even using a circular polarizer.
And of course, since there's another chunk of material in the way (the
quarter-wave plate), there will be slighly more degradation of the image
with a circular than with a linear polarizer.
Another nice way to think of circular polarization is to imagine a wave
travelling down a rope where you hold one end and the other end is tied to
a wall. If you shake your end back and forth along a line, the waves will
all lie in a plane. You can shake your end in any direction perpendicular
to the rope, and the only change will be in the direction of the
polarization. Now start moving your end around in a circle, and circular
waves will move down the rope. This corresponds to circular polarization.
If you move your hand in an ellipse with various eccentricities, you'll get
the equivalent of elliptical polarization (with various eccentricities).
If you're wondering whether your polarizer is circular or not, look through
your polarizer at a mirror and look at how dark the polarizer is that the
guy in the mirror is holding. Reverse the polarizer in your hand so the
other side of the glass is pointing toward the mirror. With a circular
polarizer, one direction will be significantly darker than the other. With
a linear polarizer, both sould be the same. The reason is that linearly
polarized light will still be linearly polarized in the same direction
after bouncing off the mirror. Clockwise circularly polarized will be
counter-clockwise after bouncing off a mirror, and will be cancelled when
it comes back.
So if you hold a circular polarizer as if your eye is the camera (with the
side that's normally screwed into the camera nearest your eye), it'll
appear light in the mirror. If you flip it over it should appear almost
black.
Some manufacturers (B+W and Heliopan, for example) sell a so-called
Kaesemann polarizer which is even more expensive. A Kaesmann type has the
foil stretched and held under constant tension in all directions. To do
this it is necessary to totally edge seal the filter in glass rather than
just bind the glasses and foil with an adhesive. This type of polarizer is
available in linear, circular and in warmtone types.
Its advantages are that the polarizing effect is slightly greater, the
filter is "tropicalized" so it is immune to moisture, fungus, etc and
it is very, very flat. So it will not adversely effect the sharpness of
longer lenses. For this reason Heliopan only supplies Kaesmann type
polarizers in sizes from 82mm up.
Q3: What can I use a polarizing filter for?
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A3: The manufacturers will have us believe that you can block out any unwanted
reflection in glass, water etc. You can *not* block out the reflections in
metallic surfaces, since they do not polarize the light.
But, although the manufacturers are right for the greater part, you will
have to use the polarizer in the right way to get the above effect. This
means, you will have to take your picture in a direction perpendicular to
the sun (i.e. the line sun-reflecting surface has to be perpendicular to
the line camera-surface), as is illustrated below:
O
sun
\
\
\
o
\
you
/
\
/
\/
---------
reflecting surface
You will be able to block out the unwanted reflections this way, dependent
on the direction of the filter. When you're standing perpendicular to the
sun, the effect will be maximum, slowly decreasing as you move in line
with the reflecting surface and the sun. Then the effect will become zero.
You can also use a polarizer to control the colour of the sky, ranging from
light blue to dark blue/grey. Since the sky is reflected light and hence
polarized, you can deepen the blue by removing light reflected of dust in
the atmosphere(haze). In this way, you are able to let the clouds almost
disappear or make them better visible. This also works best when you are
standing on a line perpendicular to the line sun-earth.
Q4: What is the best way to work with a polarizer?
A4: It depends on what you are planning to do. When taking pictures of
reflecting surfaces, it will give you the possibility to remove the
reflections, thus creating a 'better' picture than without the filter. You
can also use the polarizer to create more contrast in your pictures. The
best way to find out what you can do with a polarizer is just try it. Use a
roll of slide film (can't be corrected or ruined during printing) and take
pictures of the things you normally take pictures of, but now use the
following system: Take four or five picctures in a row of the same object,
preferably with just a short period of time between them. The first picture
should be taken without filter, just for reference. Then start with the
filter in an arbitrary position, take a picture, rotate the filter a little
(about 15 to 20 degrees ) and take the next picture, rotate the filter
again etc. until you have four or five pictures. Then move on to another
situation and repeat the above sequence. After developing the film, you
will see quite remarkable differences between the various positions of the
filter. Do try to start with the filter in the same starting position each
time you start on a new series of four or five pictures.
David Jacobson suggested you just look through the viewfinder of your
camera, but that won't give you information on what influence the polarizer
has on the autoexposure or autofocus of your camera (All cameras are equal,
but some are more equal than others - after George Orwell). Also, there are
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compact cameras and TLR's with a possibility to append filters to them, and
it is not much use looking through the viewfinder in those situations,
since you're not looking through the filter. I admit, this is a situation
that will not occur very often, but I wouldn't say it's impossible.
Q5: What effect does a polarizer have on taking pictures?
A5: As said before, a polarizer can influence the colours in your picture by
darkening them, it can block out unwanted reflections and it can disturb
your AF measuring beam or autoexposure (only linear polarizers). Also,
because it will block about at least half the available light, it will slow
your film down 1.5 to 2 stops, so if you are using a separate light meter,
set your ISO dial 1.5 to 2 stops lower to correct for the loss of light.
(You can also try measuring the amount of light through the filter with
your light meter, but this is not a very accurate way of calibrating it).
In this case, just try a few pictures, you'll soon find out what correction
to use in your particular case.
In case of doubt: A little overexposure is not as bad as underexposure, so
if you want to be on the safe side, use the 2 stops correction. Warning:
this is, if you're using normal film. Slides like to be underexposed a
little if you're not sure on the amount of light.
One other comment: the 1.5 to 2 stops is *not* valid for every polarizer.
Most of them will indeed take 1.5 or 2 stops, but it may happen that your
polarizer only takes 1 stop, or takes as much as 3 to 3.5 stops. It is
totally dependent on the brand and kind of equipment you use.
Q6: How can I find out if I really have to buy a circular polarizer?
A6: It depends on the camera you're using if you need a circular polarizer or
not. Most autofocus cameras have a semi-silvered mirror, and this can
cause a significant difference in the amount of light reaching the
photocell when using a linear or circular polarizer. Most of the manualonly cameras have their photocell in the prism, and they will not see the
difference between linear and circular polarizers. So, in case of doubt,
try a linear filter and -looking through the viewfinder- see if the reading
of the light meter changes when rotating the polarizer. If it changes more
than 1/2 stop, use a circular polarizer. This test has the most validity
if you do it in daylight, looking at a grey wall.
Q7: Why do I keep getting reflections, even if I use a polarizer?
A7: Light which reflects off any surface is polarised to some extent. The
degree of polarisation is related to the angle of incidence of light and
the refractive indices of the two materials. At a certain angle known as
"Brewsters angle", light is 100% polarised. At other angles of incidence
the light is partly polarised.
Brewsters angle is given by
Brewsters angle = arctan( n'/n)
where
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n' is the refractive index of the material giving off the
reflection (eg glass, water).
n
is the refractive index of the material through which the
light is incident (eg air).
Refractive indices of common materials
Material
refractive index
Brewsters angle
air
n=1
45
water
n=1.333
53
glass
n approx 1.5
(depends on the glass)
56
So enough theory,
All the surfaces a photographer wants to control lie in the 50 degree
range. Say you want to take a picture through a glass window. If you have
no filter on you will see a reflection. If you put on a polarizer and take
your picture looking straight through the window the reflection will still
show up. But if you move around so you are looking through the window at
an angle of 50 degrees, the reflected light will be 100% polarized. You
then rotate the polarizing filter on your camera lens until the reflected
image disappears. This is because the direction of polarization can vary
with respect to the camera depending on the angle of incidence of the
light.
- UV/Skylight Filters -
Q1: What does an UV or skylight filter do?
A1: Both of the filters filter out the UV light that can cause a blueish haze
on your pictures, since normal film is not only sensitive to visible light,
but also to UV.
A skylight filter is also slightly coloured (pink or yellow), to give your
pictures a 'warm' appearance (not so much blue).
Q2: What is the difference between a normal UV and a skylight filter?
A2: As mentioned above, the skylight filter is slightly coloured to give your
pictures a 'warm' appearance.
Q3: In what situation do I use an UV filter?
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A3: UV and skylight filters are useful when you are taking pictures in the
mountains or at sea or any other place where there is a lot of UV light.
It will filter out the blue haze that normally blurres the background of
your picture. It is also very useful when taking pictures in the snow,
since snow is a very good UV reflector.
Q4: Can I always leave the UV filter on the lens?
A4: About half of all the photographers keep an UV filter on their lens permanently, for it prevents your lens against dust, scratches and perhaps
damage due to accidentally dropping the lens. A filter is much cheaper than
a lens, so ruining your filter will not be as bad as ruining the front part
of your lens.
On the other hand, some photograpers (the other half) think it unneccesary
to keep the filter on the lens, since everything between the original
picture and your film, including filters, can cause blurrs or errors in the
image, and that's one of the things we don't want to happen.
It is just a matter of personal preference. I must admit I always have a
filter on my lens, and I take it off only for cleaning.
Q5: What effect does an UV or skylight filter have on taking pictures?
A5: First of all, it will filter out most of the UV light. A skylight filter
will also colour your pictures a little. Because the UV is filtered out,
you may notice the sky in your pictures is not as deep blue as it used to
be. This is because the UV component is now missing, resulting in another
kind of blue on your pictures. Just try a few pictures with and without
filter and see what you like best.
An UV or Skylight filter doesn't have any effect on the amount of visible
light falling through the lens, so you won't have to correct for it.
Permission to include the FAQ, as long as you don't change it without
noticing me. I'll send you the FAQ again every time I've changed it, so
you'll be up to date.
Feel free to add your own e-mail address to the header, but don't change
anything other than that without noticing me. If you get questions about
the filters that are not answered in the FAQ, please let me know, I'll
see if I can add them to the FAQ, with an answer, to make this FAQ an
authority on filters. ("All the answers to every question about
polarizers and uv filters" is the goal...)
Richard.
+--------------------------------------------------------------------+
| Lt. Frank Drebin: Nice party, Hapsburg... I see a lot of familiar |
|
facelifts.
|
|
|
|
from: 'Naked Gun 2 1/2: The Smell of Fear'.
|
+------------------------+-------------------------------------------+
| Richard Gutteling
| E-mail: [email protected] |
| Lavendelhof 9
|
or : [email protected]
|
file:///C|/faq.html (202 of 555) [7/19/2002 3:46:27 AM]
| 2991 HH BARENDRECHT
+-------------------------------------------+
| THE NETHERLANDS
| Delft University of Technology
|
| tel. (+)31-1806-14035 | Dept. of Electrical Engineering
|
+------------------------+-------------------------------------------+
================================================================================
Note 26.03
-< Diffraction, Depth of Field and Common Sense >-------------------------------------------------------------------------------Musings on Diffraction, Depth of field, and Color Saturation
by John Peele
Reference Librarian, Pepperdine Univ., School of Law Library
Internet: [email protected]
"Some would rather be fishin', but I'd rather be FOTOIN'"
Although I located math which YOU can use to correlate diffraction with f/stop
and focal length, I question the value of such data since most cameras using
35mm film do not permit the aperture to be closed to such a small diameter
that diffraction becomes a 'real' concern. Also, except that the problem may
become 'real' for large film cameras, such as view cameras, extremely rarely
do I close my lenses to where diffraction may occur. Incidentally, a neutral
density filter can be used to cut down light, while maintaining a 'reasonable'
aperture and/or shutter speed.
Recently, I read in a magazine (paraphrasing) > Good color is worthless
without good subject matter and good composition.< For the majority of my
problem photographs, diffraction and other optical conditions are not as great
a problem as 'subject failure'.
Today, I doubt if you can buy a new camera or lens for that camera in which
diffraction becomes a factor. Likewise, the other optical aberrations,
spherical aberration, coma, astigmatism, curvature of field, distortion and
chromatic aberration, have been significantly minimized or eliminated from
most lenses of contemporary design. That is, the majority of lenses today are
designed with the aid of a computer, enabling optical engineers to reduce
aberrations much more effectively than in pre-computer days. Also new glass
compositions permit these engineers to bend light in ways not dreamed of 'in
the old' days.
Continuing this semi-technical, but I hope informative, discussion. ...
Diffraction affects how light rays are bent as they pass through the lens and
the aperture controlling stop or iris. Diffraction or bending of light rays
around the edge (interior) of the lens diaphragm, tends beyond a certain point
to limit the improvement in image sharpness that can be produced by making the
aperture smaller. This occurs because normally the quantity of light through
an aperture opening overwhelms the neglible amount of light which is
diffracted. Usually, loss of some image sharpness through the effect of
diffraction is compensated for by greater image detail.
Depth of Field is the distance from the nearest point of sharp focus to the
farthest point of sharp focus, and depends on (1) the focal length of the
lens, (2) the lens stop, (3) the distance from the lens to the point focused
on; or camera to subject distance, and (4) the size of the 'circle of
confusion' [See below]. 'Hyperfocal distance' is the nearest distance in
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focus when the lens is precisely focused for an infinitely distant object.
The 'circle of confusion' describes this whole discussion. [Oops, wrong
definition!] The 'c of c' is the destruction of a dot such as a period when
light rays image that dot as a tiny circle when focus begins to degrade from
sharp focus. Such dots make up the total image of the remote subject; and
light rays should register on the film as a faithful representation of those
dots, and thus a small version of the remote image. When light rays through
different parts of a lens are focused on the film plane, the dot is formed.
But when focused in front of or behind that film plane, tiny circles are
formed as the rays no longer come to a point. Visualize the light ray pattern
as an 'X'. Note how the legs/rays spread out before and after crossing the
film plane.
Image size depends on the film format. Design criteria for 'c of c' vary
according to film format and, of course, the crispness of the lens. Although
an acceptable limit of the 'c of c' is stated in one source as "1/1000 of the
focal length" of the lens, other sources report up to 1/2000 of the focal
length. These numbers seem to convert to approximately 1/200 to 1/500 of an
inch. The eye is understood to see an image with each dot as a point; and the
image is seen as sharp when the 'c of c' is smaller than 1/100th of an inch.
Because the 'c of c' becomes larger than design criteria and will overlap
adjacent circles for image portions out of focus, critical focus should be a
primary concern when seeking well saturated imagery. Consider that diluted
black becomes grey, as does contaminated white. Thus, an out-of-focus image
of a black line on a white background, for example, will be recorded with less
edge separation than a comparable sharply focused image.
I believe color saturation to be determined primarily by the film you select,
exposure of that film, and the subject matter being exposed. Images with
primarily bright pastel colors, and few saturated colors and shadows appear
less saturated than images with a full range of light and shadow.
If your 'slides' are continuously over-exposed, expose the film at 1/3 to 1/2
stop less than metered. I expose my ASA 64 film at ASA 80, but have learned
to expose certain ASA 25 film at ASA 25. Because of the compensations made in
prints from machine printed negative films, such compensations do not always
provide me 'better' prints.
Use of a sun-shade and a polarizing filter may increase the apparent
saturation in your slides. [These are subjects for another time.] But be
aware of atmospheric haze, heat distortion as over a desert or the hot
concrete of a highway, light bouncing off of dust or finger prints on external
lens surfaces or bouncing between internal lens element surfaces, and other
diffusion causing factors, which may degrade an image and effectively reduce
color saturation.
In addition to ideas and experience from several years of enjoying
photography, the sources include: 'Focal Encyclopedia of Photography'; and
'Photography - Navy Training Courses/U.S. Government', both from the '60s.
These or similar sources are possibly available at your local library, your
favorite bookstore, or your 'full-service' photography store.
Specifically, in answer to your question, YOU can find a quite thorough
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discussion of the math for diffraction in 'Encyclopedia of Physics' edited by
Rita G. Lerner et al. ISBN 3-527-26954-1; Library of Congress Classification
No. 530.03, and the Dewey No. QC5.E545 1990.
...and this is a follow up by Jim Michael, [email protected]
...on Diffraction
Well I really didn't want to reinvent the wheel if someone else had already
cranked the numbers through, but...
Just for fun lets look at the resolution of a 1/4" branch of an oak tree at
100 meters. I like pictures of naked trees in winter, especially when you can
see superfine detail. Let's use Rayleigh's criteria to determine the limiting
resolution of a circular aperture and determine the minimum aperture required
to resolve the branch. According to Rayleigh's criteria the limiting angle of
resolution of a circular aperture is
theta=1.22*lambda/D
For the discussion,let lambda=555 nanometers which is about the peak spectral
response of the human eye, and theta is 6.35*10**-5 radians. Solving for D
gives a required diameter of 11 mm! Let's assume we are shooting with a 4x5
with a 150mm lens. The f-stop corresponding to the 11mm diameter aperture is
about f-14. Surprising result. Maybe 1/4" is too fine to try to resolve, so
let's see how fine we can resolve at f-32 at the same distance. The required
diameter for f-32 on a 150mm lens is 4.688mm. This implies a value for theta
of 1.444*10**-4 radians. At 100 meters, the smallest thing to be resolved
would be 14mm or a little over 1/2". We haven't looked at any effects due to
optical defects, but only the limiting effect on resolution of size of a
circular aperture.
================================================================================
Note 26.04
-< Guide for Forte Films used in Kodak Developers >-------------------------------------------------------------------------------Processing instructions for FORTE films in Kodak developers
all times at 68 degrees F, all times in minutes
D-76
D-76
1:1
Microdol-X
Microdol-X 1:1
HC110 Dil B
5.25
5.25
7.5
6.75
6.75
9.25
12
12
16
4.6
4.6
7
5.75
5.3
6
7.60
7.6
7
8
9.5
14
12.5
14.3
16.5
5.25
5
5.5
7.3
35mm films
Fortepan 100
Fortepan 200
Fortepan 400
120 films
Portrait
Fortepan
Fortepan
Fortepan
Pan 100
100
200
400
* Small Tank processing is based on 8 to 16 oz of developer per roll.
* Agitation should be continuous for first minute and then 5 to 7 inversion
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cycles in a 5 second time span every 30 seconds for the remainder of the
development time.
================================================================================
Note 26.05
-< Making Duplicate Slides with Enlarger >-------------------------------------------------------------------------------> How do I make duplicates of my slides?
Kodak makes a wonderful dup film in sheet sizes, numbered 6121. It is used in
the enlarger with tungsten illumination, and the image is projected on the
easel, just like paper. Of course, since the image is normally down in the
range of 1:1, learning to focus and size is critical. Using shorter focal
lengths than normal is typical, as is sizing with the focus knob and focusing
by moving the enlarger up and down. If you have an omega autofocus, you will
learn to appreciate it, if you don't already.
Also, if you put the original in the carrier emulsion side up instead of down
as usual, the resulting dupe will read right through the back side. Color
balance is handled with whatever filtering system you use for making prints.
While this may seem like more trouble, it offers a lot of flexibility.
You
can make 4x5 dupes from 35mm, 35mm dupes from 4x5, 11x14 dupes if you need
them. You can combine images, etc., too, but I suppose the Mac has made history
out of that. I expect that was how Pete Turner, among others, might have
accomplished some of his images. I loved to do this; I did a poster for the
opera _Faust_ once, combining an old man and a young man into the same person.
It was creepy. Fun.
Here in
precise
results
history
Seattle, we have a specialty lab (Duck Island Ltd.) that makes dupes to
sizes, strips them together so they can be scanned just once. It
in huge overall savings for the client. I suppose the Mac will make
out of that, too.
Larry Bullis
Shoreline Community College
From: Larry Bullis <[email protected]>
================================================================================
Note 26.06
-< Duplicating Slides - Procedures and Films >-------------------------------------------------------------------------------> I want to make duplicates of my slides. How would I go about doing this, what
equipment is required and what films to use?
Here is a summary on direct slide dups, plus better detail on the film issues:
Seems there are four options:
1) Slide Dupe Attachment. A tube w/built-in lens which mounts on the camera
body, and has a slide holder on the end followed by a diffuser. Aim at light
source of choice. If flash, I guess you'd have to run tests for exposure.
I saw one made by Cambron at ~$80. (Anyone know of others? Recommendations?)
I assume this is similar to Richard's "Nikon PB-4 w/PS-4," although I'd be
interested in the differences.
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2) Extension. Place between lens and body to give proper magnification; amount
of extension needed is determined by the focal length of the lens used. Mount
camera on copystand or tripod. Backlight and mask off slide.
3) Enlarger. Put slide in the enlarger and the camera body, sans lens, on the
platen. Image slide onto the film plane.
Focusing for this method is achieved by one of three methods: 1) a nice finder
(e.g., right angle, magnifying, etc.); 2) a custom jig which would allow rapid
and dependable switching between the camera body and a white focusing block at
the same height as the film plane; or 3) a custom jig which holds a camera body
w/standard finder and incorporates a mirror to allow you to see into the finder
(this seems easier than the other jig).
4) Duping
small box
flash and
sure. No
Device. I once saw a unit which had a mount for a camera over a
having a slide holder, a diffuser, a filtration unit, and both a
a focusing lamp in the box. It was nice, but more expensive I'm
idea who made it. (Anyone know of such devices?)
Ok, those are the better methods. (Reshooting a projected slide is also
possible, but not recommended -- it'll trash the image quality.) Seems that
option 2 -- extension -- is the cheapest do-it-yourself if you have a camera.
For films, Kodak has three options:
1) Ektachrome Slide Dupe Film 5071, for originals on E-6, optimized for 1 sec
of 3200k tungsten exposure. Come in 35mm magazines. Also available as 7071
-- same film, different formats.
2) Ektachrome SE Duplicating Film SO-366, for originals on E-6, optimized for
flash. Also available in 35mm magazines.
3) Kodak 6121, sheet film, balanced for 3200k.
There was also a special dupe film for Kodachrome originals -- Ektachrome Slide
Dupe Film, Type K, 8071 -- but I am told that this is being discontinued.
c
From: Chris Dobbs <[email protected]>
.............................................................................
Another possible set up is one my wife used while working at the photolab at
Brown University, before they sprung for an expensive duper:
use your enlarger's color head, dismounted and upside down (condenser/diffuser
pointing up). a diffuse light source is best, so any color correct diffusion
material can be used if the head doesn't have a diffusion source to begin with.
make a mask that fits the head with an opening large enough illuminate the
original (this prevents any possible flare from the surrounding area). mount
your camera, with the necessary extention to achieve a 1:1 ratio, above the head
on a copy stand or whatever, level the set up, and you're off and duping with a
color correctable light source.
From: Hank Randall <[email protected]>
...............................................................................
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>How difficult is it to do contact dupes? I would think this is especially easy
>if the original slide film or negative was uncut. Then just use an enlarger to
>expose 6 frames at a time using direct contact. Will that work?
Yes - you can contact print, but in my experience the dupe image is not as
sharp as with an optical path, and to get reasonable sharpness you must
contact emulsion to emulsion so the dupe is a mirror image. One thing
further, the original must be emulsion side up in the enlarger for the dupe
to be correct. Mirror image dupes can give focusing problems when
projected, especially when mixed with other slides.
From: [email protected] (Ross Wylde-Browne)
..............................................................................
>RE: unsharp dupes made by contact printing
> Well, if a normal large area light source is used then, yes, the contact
> dupe might not be perfectly clear if not done emulsion to emulsion.
> However, if a very sharp point source of light were used, then I think I
> can do contact print with the emulsion facing away?
If I were doing this, I would live with the wrong-reading image and note
the fact on the mount. In fact, a lot of dupes made in the past were
made wrong reading. I don't think there was a convention to supply them
that way, but there was always a question when working with dupes whether
they were coming or going. Often, dupes are encountered that are of
unknown generations -- and they look like it. Just how many times has it
been flopped?
> Do you know what film (brand and model) is low contrast enough to do
> slide to negative dupes. I want to take negative pictures of my slides.
You will need an internegative film. Kodak's Vericolor Internegative film is
available in long roll 35mm and in sheets. VIN663 is 35mm x 100 feet, 4112 is
the sheet film code. Vericolor Internegative type 2 is 4114, and comes only
in sheets.
The catalog I am using is a couple years old.
maybe you'd send it up?
If anybody has better
data,
It used to be that Interneg films were very tricky, requiring testing and
plotting results -- which most people just weren't prepared to do. It was
possible to do very fine work through internegs, but in fact most of it looked
like garbage because the color crossover was so serious. I hope the materials
that are available now are better -- or at least more forgiving.
The contrast curve is shaped so that the contrast increases as the
So you control the contrast by placing the exposure on the curve.
density.
I have not had to use this stuff now for the past almost 20 years.
missed it at all. I made good internegatives, but it was somewhat
fun as a daily activity.
I have not
lacking in
RE: Small copying unit that holds camera atop a light source ....
file:///C|/faq.html (208 of 555) [7/19/2002 3:46:27 AM]
Got one sitting on my desk. Bowens Illumitran. Heiland also made a
Repronar.
Larry
From: Larry Bullis <[email protected]>
..............................................................................
One system I have had excellent results from is with a Nikon N90 (or any Nikon
that has TTL capability) and a 105mm macro lens that will focus 1:1 such as the
AF unit. Hook a Nikon Slide Copying Adapter (Es-1) on to the end of the 105mm
lens and adjust focus. Use a TTL capable strobe (Nikon SB24 or 24, Sunpak with
NE adapters, etc.) from about 18". Using So366 Slide Dup film I got outstanding
results after the smallest amount of trial and error.
Buy the film in 100 foot rolls for consistent results. Follow Kodak's
filtration advice and make a ring-around for exposure and filtration for a
typical slide. I've used CP filters in front of the light path with good
results however Kodak will probably recommend the more expensive CC filters.
Once you zero in, duplication is easy as long as you are copying from the same
film. If you have Kodachromes and Exktachromes to copy you may need to make the
ring-around of each type.
From: [email protected]
..............................................................................
Re; Determining exposure with Slide Dupe Attachment used with flash....
One method is do tests and control exposure by keeping flash at a measured
distance from slide. Problem: How to adjust for different effective f-stops at
different magnification?
Because of this, I prefer TTL flash control.
Re: Nikon PB-4 w/PS-4 ...
PB-4 is a bellows. PS-4 is a nice slide holder with milk glass diffuser,
attaches to PB-4. The "4" stuff is old and discontinued (it's mid 70's era)
and the current item in Nikon line is PB-6.
>
>
>
>
4) Duping Device.
a small box having
both a flash and a
I'm sure. No idea
I once saw a unit which had a
a slide holder, a diffuser, a
focusing lamp in the box. It
who made it. (Anyone know of
mount for a camera over
filtration unit, and
was nice, but more expensive
such devices?)
Re: Copying devices with built in light, bellows, etc:
It gets even more complicated. For $1000 plus you get a light source, slide
holder, mount to hold camera and macro lens, and the unit *blends* x% light
coming through your slide and y% additional light to "flash" (i.e. fog) your
film to reduce the contrast. These rigs facilitate making dupes on *normal*
slide film. I've seen these, but never used. (Bowens Illumitran, ed.)
Re: 2) Ektachrome SE Duplicating Film SO-366, for originals on E-6, optimized
for flash. Also available in 35mm magazines.
This is the one I like. It was very easy to use. One test run and I was
file:///C|/faq.html (209 of 555) [7/19/2002 3:46:27 AM]
producing dupes that were excellent. An advantage of these special of these
films is that they have less contrast than normal slide films so your dupes
look like your originals; if you use normal slide film, the dupes will be
quite a bit more contrasty. You can use this intentionally to add contrast to
flat slide (at least theoretically...).
You'll need some "color printing filters"; I bought a set of Unicolor brand.
You can also use gel filters, but they are expensive. Put color printing
filter between flash and diffuser glass, not between slide and lens.
From: Richard Karash <[email protected]>
.............................................................................
Re: making slide-to-negative duplicates on Kodak's Internegative film...
The current film is Kodak Commercial Internegative Film (5325 in 35mm 100
foot rolls; not available in 36 exp). Kodak tells me it is an improvement
over Vericolor Internegative Film (still avail??).
The current film still has the very laborious balancing procedure. Requires a
densitometer. And a test exposure through a step wedge (available from Kodak).
One new wrinkle: Kodak will take your densitometer readings, run them through a
computer program and tell you the recommended exposure (no charge). They also
sell the program.
I took the film, ignored the warnings and procedure, did a couple of tests and
was able to get nice results. A pro in Canada tells me he used Fuji's
internegative film (ITN) with good results ignoring the balancing process. The
resulting prints were sharp and no noticable added grain. Colors were quite
printable. But, I suspect I was lucky and after reading up on all this, stopped
using the film. Read the Kodak publicationbelow if you are going to try to use
the film -- crossed curves apparently can really mess things up, even though I
haven't seen it personally.
Ref: Copying and Duplicating, Kodak publication M-1.
Call Kodak Pro Imaging 1-800-242-2424 ext 19 (US) or 1-800-465-6325 (Canada).
Sorry I don't know rest-of-world phone #'s.
From: Richard Karash <[email protected]>
................................................................................
To Add contrast to low contrast scenes .... duplicate!
It really works. If you photograph astronomical objects under light-polluted (I
don't mean "not-heavy", I mean outdoor lighting) skies, it's one method of
getting a black (or blue or grey, whichever you prefer) sky _and_ a conspicious
object. To achieve this some people even do second generation copies on normal
slide film. This must sound terrible to any terrestial photographer ...
Klaus
From: [email protected] (Klaus Bagschik)
..........................................................................
Re: TTL metering every slide and achieving proper exposure when using TTL
flash control using a duplicator.
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Since different slides have different densities, I prefer to sort of set the
flash for a "grey card" type of slide, then use the same exposure for all
other slides. Otherwise, if I TTL every slide I dupe, then some slides will
have the highlights washed out if the slides were overall dark, or else lose
dark details if the slides were overall bright.
From: "Francis T LIM." <[email protected]>
..............................................................................
I use Fujichrome CDU/CR56 duplicating film balanced for tungsten light with a
Durst Chromapro. I buy the film in blocks of five 100ft rolls all the same
batch so that once I,ve adjusted for the new filtration I can keep the trans
pretty close to the new filtration settings. The Fuji duping film is extremely
red sensitive so I generally give Kodachrome originals between ten and fifteen
more units of cyan filtration than Ektachromes. I dupe a wide range of
materials, and have found that emulsions vary tremendously over the years of
their production. You just develop an eye for variations in emulsion
filtration over time. I might add that the Fuji duping film is rated as the
longest lived duping film when being projected regularly.
Ted Bundy
Arizona State Museum
[email protected]
================================================================================
Note 26.07
-< 18% Gray Card Reference Articles >------------------------------------------------------------------------------->Information on the 18% Gray Card
Found several articles in my files on the gray card that might be of interest.
All by William Hyzer.
"Photometering Devices & Techniques." Photomethods 33:8. Aug. 1989
"Reflections on the 18 Gray Card." Photomethods 32:4. April 1990.
"More Reflections on the 18% Gray Card." Photomethods, p. 14. Aug. 1991.
"The origin of the mystical 18% reflectance is to be found in a psychophysical
visual scale which was experimentally determined anout 60 years ago by the
Munsell Color Company." in August 1993 Photomethods.
Gene,
"Eugene R. Prince" <[email protected]>
================================================================================
Note 26.08
-< Cross-processing - what goes on? >------------------------------------------------------------------------------->
I need help in finding information on cross processing film. For
> instance, when a slide film is processed through C41 what exactly is
> happening in the process? Also what happens when a negative color film
> is processed through E6? I am doing a term paper for school and unable
> to find adequate information on this topic. Can someone please help?
In all of today's color film and paper processes (except Ilfochrome/Ciba-
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chrome), here is what happens: In the film or paper in multiple layers are
silver halide particles surrounded by dye coupler molecules. These dye
coupler molecules could be thought of as part of a dye molecule, with the
other part supplied by the color developing agent in the color developer.
When the color developer starts to reduce (un-oxidize) the exposed silver
halide particles (to form metallic silver), development by-products in the
vicinity of the developing silver halide particles combine with the dye
coupler molecules to form a visible dye. Depending on what layer of the
film or paper this is taking place, magenta, yellow or cyan dye would be
produced. After this step, the silver has done its job and is no longer
needed in the film or paper. The bleach re-oxidizes it to silver halide,
and the fixer removes it.
The only difference between a negative process (color negative film or
color negative print paper) and a positive process (color slide film or
color positive print paper) happens BEFORE the film or paper gets to the
color developer. In a positive color process (like E-6), the exposed
silver halides are developed in a black-and-white developer (the FIRST
developer), producing a negative black-and-white image. The color couplers
aren't affected. Then, the UNEXPOSED and UNDEVELOPED silver halide particles
are chemically fogged (or in the old days were exposed to light) and rendered
developable. This is the "reversal" step which results in a positive image.
The film goes to the COLOR developer where the unexposed, undeveloped but
chemically fogged particles are developed, forming the dye molecules in their
vicinity, as described in the preceeding paragraph. From here on the
process is essentially the same as color negative process.
Now to answer your questions. When a color slide film is processed in C-41,
a color negative image results because you are "jumping" into the process
without going through the FIRST developer or REVERSAL. This color negative
image will be high contrast, very color-saturated, and without the orange
mask familiar in color negative films. I have fiddled around with such
images, usually sandwiching them with the orange mask of color negative film
and made prints. The prints are wierd, but are fun to play with for
surrealistic results. Color slide film wasn't designed to be used in this
way, so the results are highly unpredictable. (BTW, if you want to do this,
underexpose the film by 1 or 2 stops).
When a color negative film is processed in E-6, a positive image WILL result,
but I don't think the results would be very pleasing because color negative
films have that built-in orange mask.
I hope this answers your questions. Did I go too deep, or not deep enough?
Are you doing your own processing? Commercial photofinishers get very
confused when you ask them to cross-process film.
If you need more information, send me your snail-mail address and I can send
you some more articles.
Ron Speirs, Evans & Sutherland Computer Corp., Salt Lake City, Utah
[email protected]
or
[email protected]
================================================================================
Note 26.09
-< Commercial Silver Recovery Units FYI >file:///C|/faq.html (212 of 555) [7/19/2002 3:46:27 AM]
------------------------------------------------------------------------------->Besides just flowing used fixer through wads of steel wool so that silver
>replaces iron and iron washes down the drain, is there another way to recover
>silver from used fixer?
For those in need of reducing the amount of silver exhausted fixer for disposal
and recovery there is a beautufull electrical silver recovery unit for
*smaller* labs. It is Marketed by Byers Industries in Portland Oregon. The
recovered silver is in the range of 95+% pure silver and may be marketed for
further purification at a higher *rate of return* than the iron or zinc
exchange method. Their address is: Byers Industries, Inc., 6955 SW Sandburg
Sreet., Portland, OR 97223-8092 ph (503)639-0620 or (800)547-9670 and their
fax is (503)620-4798
According to the last brochure I received (1992) the make units to recover the
following Capacities (in Troy oz) 25, 50, 60, 120, 180, and 360. The recovery
is 98% flake silver. Unit prices as of my brochure range from $390 to $2500
Note 27.01
-< BIG photographers databank!!!! >-------------------------------------------------------------------------------> NEED INFO ABOUT PHOTOGRAPHERS? Check out this database! Look for some
of your favorite instructors on this list to see where they have
exhibited and where some of their work is collected.
For the past two years, one component of the NEH and Pew supported
collaboration between George Eastman House and Harry Ransom Humanities
Research Center/U Texas has been documentation of photographic
exhibits and photographers.
To date, those who TELNET to MANNING.HRC.UTEXAS.EDU and sign on as GUEST
have a couple of ways to access the 2100 exhibitions and participants
processed so far. Use 'E' (as in EXHIBIT) at the main menu for the
CHRONOLOGICAL approach. Every year from 1839 to 1995 is now
represented.
In the database, EXHIBITIONs are treated as 'entities' in the
relational structure which also includes BIOGRAPHIES of makers of
photographs, CATALOG records for individual photographs, BIB-CITATIONS
for sources cited in any of the other entities, and INSTITUTIONS to
describe the public collectors and exhibitors of photographs. What
makes it truly a database is that all these entities are interlinked.
There are currently 19,928 photographers who have 1 or more exhibits listed.
There are 43,131 exhibition occurrences (averaging 2.16/photographer).
Exhibitions, of course, vary from solo to large group shows (see "Family of
Man" - hint; search 1955, or Steichen). Current average is 20 photographers/
20 photograpehrs/exhibit.
An alternative to YEAR is to look at MAKERs (photographers) (selection 1 on
main menu). Do the obvious, select Stieglitz (remember we're mixed case), and
you'll get vitals on the Alf, as well as counts of exhibits in which
he had work (in his lifetime) as well as exhibits which he jurored/curated.
You can branch to either of these lists of exhibits and see vitals about the
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exhibit as well as who else was in it, etc.
and forwards are possible).
(Great recursive loops backwards
In a smaller number of cases, the exhibit records link to GEH or HRC catalog
records (and vice versa). For example, both GEH and HRC loaned photos to
"Art of Fixing a Shadow" (you'll find it - complete with travel venues under 1989, or under any of the 4 curators).
1. The 2100 exhibitions listed to date are only the tip of proverbial
iceberg. You may expect this to easily reach 3000 within the next year.
2. The project scope ONLY encompases exhibits at public institutions such
as museums, libraries, camera clubs, etc. With the exception of '291' (already
processed), exhibits at 'commercial' galleries aren't included.
3. In addition to a steady stream of new data, there is a major new SEARCH
feature (might be ready in time for Christmas) in the works. It will permit
selection of exhibiting and/or collecting INSTITUTIONS (active and defunct)
with presentation of INSTITUTIONs' vitals as well as opportunity to branch
either to its population of photographers (analogous to front section of
--Index to American Photographic Collections--) OR to its exhibition
history.
In fact, several hundred of the collections participating in --Index-- have
this past year provided their institutional exhibition histories (not yet
data entered). There are already substantial samplings for MOMA, RPS,
Camera Club of New York, SFMOMA, MOPA, and many others. We've always tended
to build the data in advance (and in anticipation) of the search engine.
Feedback has always been useful to this work. Nominations of exhibits to
include are most welcome. Exhibit catalogs are the most authoritative
sources, although we do use (and cite) reviews, annual reports, etc.
My favorite anecdote from work to date is the letter received from Barry
Goldwater whom we wrote after running across his name in several 1930s
'Salons'. As if just waiting for someone to ask, he has handy a listing
of all 135 exhibits in which he particiapted before going off to 'war' after
which he returned and got busy doing 'other things' than photography. We don't
yet have 135 (lifetime) exhibits for STIEGLITZ!
Andrew Eskind
Project Director
George Eastman House
716-271-3361 ex 353
716-271-3970 (fax)
[email protected]
================================================================================
Note 27.02
-< California Museum of Photography on Internet >------------------------------------------------------------------------------->Does anybody have any information on how one accesses the California Museum
>of Photography (Riverside) exhibitions "posted" on the Internet exhibit?
Just type "gopher galaxy.ucr.edu" at the unix system promt.
file:///C|/faq.html (214 of 555) [7/19/2002 3:46:27 AM]
Once you're in the root server at UCR, choose #6 (Campus Events),
then #2 (California Museum of Photography), then #3 (Network
Exhibitions). From there, download whatever sounds interesting.
From: [email protected] (Paul R. Howard)
================================================================================
Note 27.03
-< Dealing with VERY contrasty negatives >------------------------------------------------------------------------------->I'm printing some glass negs done in the Himalayan range in 1931. The
>contrast range of the negs exceeds that of the paper.
Depending on your needs, you might want to consider two
alternatives to making a mask.
One is a little messy, but imitates POP (printing-out-papers) and
therefore is self masking for the darkest tones. Use test strips
to find the best printing time for the lightest tones on a normal (or
higher) grade of paper. Then develop a sheet paper for about one
minute, before exposure. Carefully drain or squeegie it ( a couple
of drops of Photo-flo per liter helps) and enlarge onto it for part
of the exposure. Let the print develop for about one minute,
complete the exposure and develop the print normally. Contrast is
determined by the first exposure--the longer it is, the greater the
overall contrast. [I first encountered this method in and article by
David Vestal].
Obviously this is only for enlargements. If you can rig up a
jig to align a piece of plastic or a developer tray under the
enlarger, you can be pretty accurate for repeated placing of the
paper, especially if you trace out a piece on the plastic or tray
with a marker. You should also test for safelight fog, since the
paper is exposed to it for a long time, compared to normal processing
procedure.
The other alternative is based on the Sterry process and can be
used for any black-and-white print. It was proposed by David Kachel
in a series of articles on contrast reduction and involves bleaching
the print in a _very_ dilute solution before development. The
easiest method is to use the bleach from Kodak's sepia toner kit.
Mix to make a 1 liter solution; take 100ml of that and make up
another liter. Begin your experiments with 10ml of the second
solution added to 1 liter of water. Bleach the exposed print (on #2
or #3 paper) for 1-2 minutes and then develop normally. If you need
lower contrast than 2 minutes yields, add more bleach from the second
solution in 10ml increments. If you need less contrast reduction, use
less bleach. A liter is good for no more than 8 8"x10" prints,
including test strips.
Both methods can offer an amazing degree of contrast reduction
for the nastiest of those "hard as nails" negatives and are much more
convenient than making masks. I have not used the first method since
I read about the second, but it was very manageble, if a bit messy.
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************************************
*
Nathan Prichard
*
*
Kentucky Historical Society
*
*
Frankfort, KY
*
*
[email protected]
*
************************************
================================================================================
Note 27.04
-< Contrast Control with the Sterry Process >-------------------------------------------------------------------------------The Sterry Process
a process for tone control
(c)1993 James W. Henderson, RBP
The Sterry process was developed by John Sterry in 1904 (LeClerc 1904). He
found that a weekly ammoniated dichromate solution would reduce formation
of silver proportionately more in the highlight area than in the shadow
area of the print. He exposed photographic paper for the highlight detail
of the negative, regardless of the amount of overexposure that occurred in
the shadow area. He then immersed the print in the bichromate solution,
rinsed it and processed it normally. The resulting print exhibited "...a
very great softening of gradation." The Sterry process was later
recognized as one of true proportional contrast reduction, as contrasted
with an overall reduction in density (Sowerly 1956).
Today, the Sterry process exists as an obscure process in the footnotes of
a few esoteric photolab manuals (Wall & Jordan 1976). There are several
instances, however, when the Sterry process could save a great deal of
time. One such instance is X- ray reproduction. Normally photographed on
sheet or roll film, processing is done around a time-temperature
combination that hopefully yields a negative printable on a contrast 2
(normal) printing paper. A slightly contrasty negative is still capable
of reproducing the full tonal range of the original X-ray on a grade 1 or
0. Occasionally, however, the contrast range of the negative exceeds even
that of a grade 0. This situation generally creates a great deal of
frustration in the darkroom, generally remedied by excessive dodging and
burning, or even re- shooting.
Understanding how the Sterry process "...reduces contrast" and results in a
"...very great softening of gradation" will permit its full potential to be
realized and applied in a practical way.
both film and paper can be
physically described by their characteristic curves. Exposure of light
sensitive material to light results in density being deposited in the
emulsion. The amount of silver deposited is directly proportional to
exposure.
If increasing exposure is plotted against the resulting increase
in density, a sigmoid shaped set of points is obtained.
Of importance to this discussion are two points. A minimum exposure
results in a noticeable density increase at a point that represents the
darkest shadow detail in the original scene. The point at which maximum
density is obtained that represents the highlight detail of the original
scene represents the second point. The arithmetic difference between these
two points is called the density or exposure range. Both negative films
and positive papers are similarly described by their response to exposure
file:///C|/faq.html (216 of 555) [7/19/2002 3:46:27 AM]
ranges which result in predictable exposure/density ranges. This causal
relationship between exposure and density becomes crucial to an
understanding of the meaning of contrast as applied to photographic papers.
Unfortunately, there has developed some confusion between just what is
meant by "shadow" and "highlight" detail when comparisons are made between
negative and print characteristic curves. These two terms are descriptive
of the original scene. They correlate with the minimum and maximum density
points on the negative curve. They are incorrectly interchanged with the
minimum and maximum density points on the paper curve.
When a negative with a given range of densities is placed between the light
source and the paper in an enlarger, the thinnest part of the negative
allows the greatest amount of light to reach the paper. This produces the
maximum density in the print, which in fact, is the shadow detail of the
original scene.
The case is similar with the densest portion of the negative when printed.
This results in the minimum density on the print, which is the highlight
detail of the original scene. Adams states that for the negative, one
should expose for shadow detail and develop for the highlights; whereas for
the print, one should expose for the highlights and develop for the shadows
(Adams 1968).
The concept of "contrast" relies on an understanding of the role do
exposure and density ranges as they relate to both film and paper. When a
negative of known density range is matched with a paper whose exposure
range--or scale, as it is sometimes called--matches the negative's, the
resulting print will produce the entire range of tones (densities) present
in the negative.
The term "contrast" refers actually to the density range
of the negative which can be printed on a paper of known exposure scale.
If a print is attempted from a negative whose density range is greater than
the exposure range of the paper, one must choose to print either for the
highlights and sacrifice the shadows, or the converse.
Several solutions to this unpleasant situation are possible.
Expand the
exposure range of the paper either by choosing a lower contrast grade with
a longer exposure range, or by expanding the exposure scale of the
available printing paper. On the other hand, the negative can be re-shot
to match the exposure (contrast) range of the paper. On one likes to
consider the prospect of re-shooting, and some very contrasty negatives
from bygone ages cannot be redone. If the lowest contrast grade is
already being used, one is left with one remaining option: The Sterry
Process.
The success of the Sterry process is due to its oxidation of metallic
silver from proportionately higher areas of density than from lower ones.
This means that the upper densities of the print are lowered in value,
permitting additional exposure before reaching maximum density again.
Exposure is then made to obtain detail from the highlight portion of the
negative. An appropriate quantity of the Sterry solution is added to
suppress maximum print density. Eventually, the density range of the
negative can be matched to the exposure scale of the print paper, and a
"print of great brilliance and substance" obtained.
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Negatives that exceed the exposure range of the paper being used can be
printed by simply varying the concentration and/or the time of the
bichromate presoak. In effect, it is possible to take a negative that
should be printed on a grade 1 and print it on a grade 2.
The actual procedure is a relatively simple one which requires simple
equipment and readily available chemicals (Wall & Jordan 1976). First
prepare a stock solution of the Sterry solution:
potassium bichromate
5 grams
ammonia (28%)
1 milliliter
distilled water to make 100 milliliters
The actual working solution is then prepared from the stock
solution:
Stock solution
water to make
6-20 milliliters
300 milliliters
Immerse a print exposed for negative highlight detail in a working solution
at 68 degrees for two minutes, agitating constantly. Place the print into
a water bath, rinsing for one minute. Remove the print and allow the
excess water to drip off.
Place into the normal developer and process for
the usual time required for full development. Carry-over bichromate will
eventually contaminate the developing solution. It should be discarded
when a decrease in paper speed and maximum density are observed. Stop,
fix, and wash normally.
The effect of the Sterry process will also vary depending on the type of
printing paper used. Maximum effect has been obtained experimentally by
the author using bromide enlarging papers such as Agfa Brovira and Oriental
Seagull. A small effect has been obtained using Ilford Ilfobrome.
Resin-coated papers were least affected by the solution. Note, however,
that resin- coated papers retain less of the bichromate solution in the
emulsion than do the traditional fiber papers. It may be possible to
obtain a greater effect with a shorter rinse, or with no rinse at all.
The potential application of this procedure to the sometimes excessive
contrasts encountered in a photographer's routine printing is certainly
great enough to justify its use. It is ironic that some of these older
formulae are now working their way back into circulation. With more and
more emphasis on tine tuned printing, the Sterry process might just be here
to stay.
Bibliography
1.
Adams, Ansel. The Print. Morgan & Morgan, 1968.
2.
Carroll BH, Higgins GC, James TH. Introduction to Photographic
Theory: The Silver Halide Process. John Wiley & Sons, New York, 1980.
3.
Focal Encyclopedia of photography, Volume III. Focal Press,
New York, 1965.
4.
Horder A, ed. The Manual of Photography, 6th edition.
Chillon Book Company, New York, 1971.
6.
Sowerly A. Dictionary of Photography, 18th edition.
Philosophical Society, New York, 1956.
7.
Todd H and Zakia, Richard. Photographic Sensitivity. Morgan
file:///C|/faq.html (218 of 555) [7/19/2002 3:46:27 AM]
& Morgan, New York, 1979.
8.
Wall EJ, Jordan FI. (Revised by J Carroll). Photographic
Facts and Formulas. Prentice-Hall, Inc., New Jersey, 1976.
++++++++++++++++++++++++++++++++++++
+
Jim Henderson, RBP
+
+ 804 Center Street
+
+ Oregon City, OR 97045-1951
+
+ email: [email protected]
+
+ voice:
(503) 655-6817
+
++++++++++++++++++++++++++++++++++++
================================================================================
Note 27.05
-< PSA (Photo Society of America) address >-------------------------------------------------------------------------------> What is the address of the Photographic Society of America?
Here it is :
Photographic Society of America
3000 United Founders Blvd., Suite 103
Oklahoma City, OK 73112-3940
(405) 843-1437
================================================================================
Note 27.06
-< Comprehensive Copyright Info Source >-------------------------------------------------------------------------------I found this to be useful, so I thought I'd pass along the info to the list.
The FAQ even includes a section on international copyright.
This FAQ is available for anonymous FTP from rtfm.mit.edu [18.70.0.209],
in directory /pub/usenet/news.answers/law/Copyright-FAQ, files part1 part6. If you do not have direct access by FTP, you can obtain a copy
via email: send a message to [email protected] with the following
lines in it:
send
send
send
send
send
send
quit
usenet/news.answers/law/Copyright-FAQ/part1
usenet/news.answers/law/Copyright-FAQ/part2
usenet/news.answers/law/Copyright-FAQ/part3
usenet/news.answers/law/Copyright-FAQ/part4
usenet/news.answers/law/Copyright-FAQ/part5
usenet/news.answers/law/Copyright-FAQ/part6
from: Eric, [email protected]
================================================================================
Note 27.07
-< Photokina address in US >------------------------------------------------------------------------------->Does anyone know where to obtain info about Photokina without having to
>contact the Photokina "organization in Germany?>
The contact for the Photokina in the USA
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nearest to Rochester is :
Hans J. Teetz
Cologne International Trade Fairs inc.
c/o German American Chambers of Commerce Inc.
40 West 57 St New York NY 10019-4092
Tel : 212-974-8836 or7
Fax : 212-974-8838
From: Johan Wesemael, Belgium <[email protected]
================================================================================
Note 27.08
-< Basic Astrophotography Pointers and Info >-------------------------------------------------------------------------------> I'm interested in a general overview of what is required to photograph through
> a telescope. I have the camera, a buddy of mine has the telescope. Is there an
> easy and cheap way to do this or does it require a major investment in
> equipment and money. Right now it's just something I'd like to try and see
> what happens. (i suppose you could say it's just a "shot in the dark" <grin>)
How cheap and easy astrophotography is depends on what objects in the sky you
want to photograph. It also depends on what type of telescope and mount you
intend to use. First the mount that the telescope is on should be a mount that
has a clock drive attached so that it moves as the earth rotates. Now if you
are happy doing shot of the moon and some planetary work all you will need is
a telescope adapter and T-ring for your kind of camera. Now if you think you
want to photograph deep sky objects you also need equipment to guide the
telescope during the exposure to keep the stars in the field from trailing.
Deep sky work is by far the most difficult for a first time effort. The
exposures can range from 10 to 90 minuets in length and need to be guided the
whole time. A trip to your local libaray should find you some books on the
subject. Look in the area where you find books on astronomy. There a few
written on the subject.
From: "Michael E. Mitchell co230-0547" <[email protected]>
Without more information regarding what you'll be photographing, the answer to
this question is that photographing through a telescope can either be very easy
or quite difficult. Anyway, here is my attempt at a general overview of
photographing through a telescope.
If you are photographing terrestrial subjects during the day, all you need is
relatively inexpensive camera to telescope adapter which can be purchased from
most of the telescope suppliers found in "Sky & Telescope" magazine.
If you are trying to photograph celestial subjects, obtaining satisfying
results could be a difficult and expensive task. Generally, telescope optics
are rather slow compared to camera lenses. Reflecting type telescopes
generally range from around f/4 to f/8. While folded optic and refractors
range from about f/8 to f/16. Given the dimness of the subjects and the motion
of the earth, attempts to photograph celestial objects without motion
compensation results in streaked images. To obtain good results you will need,
at a minimum, a telescope with what is known as a "polar axis mount" and "clock
drive". This equipment allows the telescope to rotate at the same speed and
along the same axis of motion as the stars. This set-up will work for
file:///C|/faq.html (220 of 555) [7/19/2002 3:46:27 AM]
relatively short exposures.
Longer exposures requires equipment which allows you to make fine adjustments
to the tracking to compensate for errors in alignment and motor speed. Longer
exposures may also require the use of a "cold" camera or hypersensitized film
in order to overcome reciprocity failure. An even more expensive option
involves CCD cameras and computer interfaces.
The film of choice for serious astrophotographers is Kodak 2415 tech pan B&W
which has extended sensitivity in the red region of the spectrum. If you are
going to take relatively short exposures then almost any high speed B&W or
color film can provide satisfactory images.
I should mention that the moon is the easiest celestial object to photograph.
Even with relatively slow optics and ISO 200 or faster film, you should be able
to use shutter speeds which are fast enough to keep motion blur to a minimum. I
recommend a spot metering mode for the moon if your camera has this capability.
I hope you find the information helpful. Sky & Telescope magazine sells a
number of books on the subject you may (or may not) find interesting.
Tom Koger, [email protected]
================================================================================
Note 27.09
-< Image Usage Rights - A primer >-------------------------------------------------------------------------------Image Usage Rights - a short primer
>We are trying to find out how others in our market area, and other markets,
>are handling usage rights, multiple usage rights, and violation of usage rights
>in light of the new copyright laws. Are people spelling out the limitations in
>a shooting agreement? Are studios and photographers specifying certain values
>for image use at a trade show, national ad, catalog usage, one time usage,
>multiple usage etc. How are others setting and enforcing limits?
note: All references to "he" is for convenience.
It can also be "she".
As a Commercial Photographer based in Santa Fe, New Mexico, I practice image
usage rights with every project negotiation that comes my way. Although an
uncomfortable topic for some Art Directors and Clients, it's an issue that
needs to be addressed during the initial phone call or meeting since, this is
the foundation of our business. My perception is that speaking about usage
rights is like speaking Chinese. A.D.'s and Clients are fearful to talk
about them, because they simply don't understand them and how a bottom line
figure is arrived at through them. We hold all the power here so, it's easy
to see why there's a certain degree of discomfort. With a good command of
this language it is in our best interest to add education along with price
quotation.
Allow me to refer you to a book every photographer-for-publication should
have next to his business telephone. It's called Pricing Photography,
written by Michael Heron and David MacTavish. It's an Allworth Press
publication that is distributed by Amphoto. Before you price another job for
a commercial client, GET IT. It will give guidelines you need to negotiate
fair prices for estimating/pricing in the client's best interests and more
file:///C|/faq.html (221 of 555) [7/19/2002 3:46:27 AM]
importantly your business' survival.
Educating your client about how your pricing is structured, and having
legitimate justification as to why, is the best way to arrive at an agreeable
price. It helps balance the power struggle, making them feel more
comfortable with you, building trust, and ultimately building a long term
relationship with them. Recently, I had a client who informed me that he had
never heard of usage rights prior to meeting me and that he simply bought all
the images from the photographer after the shoot was completed. This is
alarming. The negotiating process took over a month, of albeit firm words on
my behalf, before we settled on an agreeable price. Whether the client calls
me back or not, I have set a standard of my business practices and have
prepared the way for the next person.
This gave me a strong indicator as to how some photographers were making
money in this area and it has caused me considerable concern since, they're
not playing with the same set of rules I am/we are. i.e. Some photographers
shoot for a "consumer market" where images become a product that is sold like
any other commodity over the counter. This is fine if this is what they
choose to do for a living, I don't have a problem with this. We however, as
Commercial Photographers shoot for publications where what is sold is a
LICENSE to use the image(s) for a stated period of time. Apparently, these
consumer based persons have crossed this "boundary" by shooting commercial
jobs for publication and pricing/selling them as a consumer images. This is
destroying the legitimacy of pricing structures on our end of the industry
and it becomes a battle to negotiate under these conditions.
Commercial Photography pricing takes a good deal of research on your part in
order to arrive at an accurate and fair price. Some of the questions you
must ask are:
What is the image being used for?
How many images do you need?
Will they all be used for the same purpose?
How long do they need to use it for?
Where will it appear? How big?
Find out for yourself how much it costs your client to run an ad in that
space. i.e. Full page, half page, color, black & white. Will it be used on
an outdoor billboard?
These questions are IMPERATIVE in how one prices the job. If the client is
willing to spend $12,000 per year on an outdoor billboard, on an interstate
highway running through the heart of town and your image is appearing on it,
you should charge say 10-12% of that since, your image IS the billboard (for
one-year, exclusive usage). If they're willing to pay that much for that
type of ad space, they MUST be expecting handsome revenues in return for it.
Your image is what sells their product therefore you should keep control of
what rights are released and be properly compensated for your vision. If the
client asks for a "buyout" you should charge a substantially higher price.
In fact, discourage them from doing that since it probably won't be in their
best interest anyway. Ads change from year to year and the prospect of
losing ALL your rights to re-sell the image in the future is not attractive.
Heron and MacTavish's book provides great insight about this topic.
Usage rights violations shouldn't be a problem if everything is clearly
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spelled out on your invoice face, the terms of agreement on the reverse side,
and as stated in a related delivery memo that is signed by the client and
returned to you. Terms should include a clause that states "usage rights
granted upon payment in full." In other words, you must be fully paid before
the image appears in any type of publication. If a violation arises, you
hold signed legal documents stating what agreements were made and you should
be paid compensation accordingly.
I dealt with a client recently who balked at the prices I presented and
threatened to have another photographer shoot images like mine, to get the
price he was looking for. Unless he owned the rights to that image, he
shouldn't even have thought of doing that. The term for this is copyright
infringement. It's against the law, and photographers should be weary of
A.D.'s or Clients who ask to have something shot, "that looks like this
photo." Sometimes we have to explain specific copyright laws to keep things
on track.
STUDENTS TAKE NOTES! Image usage rights are one of THE most important
aspects to your business' survival. Knowing how and what to ask your clients
is the key to quoting prices for your images or for a job estimate. If you
don't enforce these pricing concepts, nobody will do it for you. If we as a
photographic community don't enforce them, nobody else will. Educate your
fellow photographers even though they are your competition in the market
place. It's the only way that we can keep a standard of living for
ourselves.
In terms of pricing; "lowballing" just to get a job simply brings prices down
for everybody else. Say a client goes back to his office very satisfied with
the low price he got on this year's photography. When it comes time for him
to create the budget for next year's advertising photography he's going to
say to himself, "I don't need anywhere near as much as I thought to get this
photography done since, Cheap Photo, Inc. gave me such a great deal."
So,
down comes his budgetary axe. Down went the possibility to make more money
next time, not just for you, but for all the photographers he deals with on
other projects. Forget about that new piece of equipment you really needed.
Rate stagnation causes virtually zero business GROWTH. This becomes
self-destructive and industry wide destructive.
When a client asks you "what's your Day-Rate," don't quote a figure unless
you know the answer to how the image(s) will be used. Say that you'll call
them back in a day or so to discuss the job. It's perfectly acceptable that
you need time to think about it. Tell them why so that they feel more
comfortable.
Joining your nearest chapter of the Advertising Photographers of America
(APA), or the American Society of Media Photographers (ASMP), gives you
invaluable information, forms and guidelines about these issues and numerous
others. They are worth the price of membership alone. It keeps crucial
standardization of our industry's business practices and allows you to make
decisions with confidence. This in turn allows you to sound not only
convincing to your client but, genuine in your negtiations.
Don Werthmann
[email protected]
Santa Fe, New Mexico
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................................................................................
info on membership to ASMP is available from RIT by e-mail by sending a note to:
[email protected]
and saying INFO-ASMP$txt in the Subject: (not body) line of
the message.
================================================================================
Note 27.10
-< Photo Artisans Guild info >-------------------------------------------------------------------------------> what is the APGA and where are they located?
The address for the American Photographers Guild of Artisans is
212 Monroe, PO Box 699, Port Clinton, OH 43452
(419)732-3290
================================================================================
Note 27.11
-< Reversal Processing of Ilford Films >-------------------------------------------------------------------------------ILFORD TECHNICAL DATA - REVERSAL PROCESSING OF ILFORD NEGATIVE FILM
Reversal processing enables black and white transparencies to be produced
directly from ordinary negative materials exposed in camera the normal way.
The basic reversal process starts with development of the negative image. At
this point the used silver halide is not fixed out as in normal film
processing, but completely bleached away, using an acid bleach (see warning).
This leaves the remaining silver halide ready to be light-fogged and then
re-developed to form the final positive image.
Between the various stages of the process, washes are used to prevent
contamination of each new processing solution by the previous one. There is
only one critical stage in reversal processing; the first development. The
first negative image must "use up" just the right proportion of the emulsion,
so as to leave behind the correct amount of silver halide to give the desired
positive image at the end of the processing sequence.
RECOMMENDED FILMS
The suitability of a negative film for reversal processing depends largely on
its inherent contrast. Little can be done to change the contrast appreciably by
changes in processing. So choose a film for reversal processing according to
the ultimate contrast required in the final positive image. For this reason
FP4/FP4 Plus is recommended for a moderately soft graduation image with
pleasing tones. PAN F gives somewhat higher contrast and pleasingly bright
positives. Particularly suitable for copy slides of photographs. We do not
recommend reversing high speed films, as they are likely to be too low in
contrast.
REVERSAL PROCESSING PROCEDURES
These are two methods available to make transparencies from black and white
films. These are Kodak's T-Max 100 Direct Positive Film Developing Outfit and a
user prepared procedure. Each has its own unique quality, but work on the same
principals.
file:///C|/faq.html (224 of 555) [7/19/2002 3:46:27 AM]
Black and white reversal processing involves six main stages:
1. First development - here the exposed image is developed to a negative.
2. Bleaching - here the negative image is completely bleached away.
3. Clearing - this is to clear away all traces of the powerful bleaching bath,
and the slight stain it leaves behind.
4. Re-exposure - this is a total fogging exposure to make the remaining silver
halide readily developable.
5. Second development - all the residual silver halide is developed fully, to
form the positive image.
6. Final fixing - this is an optional stage which removes any last traces of
silver halide that did not develop and leaves the image clean and fully
transparent in the clear parts.
7. Final washing and drying are quite normal.
T-MAX 100 DIRECT POSITIVE FILM DEVELOPING OUTFIT
When using this kit, we would recommend the following exposure modifications
coupled with the corresponding development times. The times are given for first
development and are a GUIDE ONLY. Modification may be needed depending on the
output required.
FILM
EXPOSURE (STOPS)
PAN F
+1
FP4 Plus
+1
400 DELTA*
+2
*May produce transparencies of low contrast.
FIRST DEVELOPMENT TIME
3 minutes
6 minutes
6 minutes
USER PREPARED REVERSAL PROCESSING PROCEDURE - SOLUTIONS REQUIRED
A. Developer - Use either ILFORD Bromophen 1+1 with water or ILFORD Universal
Paper Developer diluted 1+15 with water. To one liter of the working strength
developer add Sodium Thiosulphate crystals (hypo) in the following proportion:
PAN F
FP4/FP4 Plus
8g
12g
B. Bleach - Mix the following solution: Potassium Dichromate 10g, water
liter; when dissolved add, slowly and carefully, 10ml of Sulfuric Acid
(concentrate). As you pour in the acid to the dichromate solution, much
will be generated, so pour in the acid very slowly and carefully. IF IN
ASK A QUALIFIED CHEMIST TO MIX THIS FOR YOU. Protect your skin and eyes
using rubber gloves and protective eye wear.
1
heat
DOUBT,
by
******************************************************************************
* WARNING!! Concentrated Sulfuric Acid is DANGEROUS and HIGHLY CORROSIVE!! *
* ALWAYS pour the acid into the water, and NEVER the water into the acid! *
* KEEP OUT OF THE REACH OF CHILDREN!!! CAUSES severe burns. May be fatal *
* if swallowed. DO NOT get into eyes or onto skin or clothing. Keep out of *
* the reach of children. In case of contact:
*
* EXTERNAL: IMMEDIATELY flush with tap water, then water containing sodium *
* bicarbonate. INTERNAL: DO NOT give an emetic. Give whites of eggs beaten *
* with tap water, milk of magnesia or milk. GET MEDICAL ATTENTION AT ONCE! *
******************************************************************************
file:///C|/faq.html (225 of 555) [7/19/2002 3:46:27 AM]
C. Clearing solution - Sodium Sulphite (anhy) 50g. Water to 1000ml.
D. Second Developer - It is most exonomical to re-use the first developer over
again. This is not ideal because of the added (but unwanted here) solvent.
Ideally you would used the same developer, but without the added Hypo.
E. Final Fix - Universal Fixer 1+9 or any other available fixer.
THE REVERSAL PROCESS SEQUENCE
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
First development
Wash
Bleach
Rinse
Clear
Rinse
Second exposure
Second development
Rinse
Fix
Final wash
Dry
12 minutes
5 min., perferably running water
5 minutes
1 minute
2 minutes
30 seconds
30-60 sec to white light
6 minutes
30 seconds
1 minute
10 minutes
this file was made available to this FAQ throught the courtesy of Ilford Corp.
================================================================================
Note 27.12
-< Bellows - basic instruction in making one >------------------------------------------------------------------------------->Does anyone know how to make bellows? Is there a published set of plans?
I've never seen a published set of plans but I've made plenty of bellows in my
time. I'm currently using a 2x3 Century Graflex that I restored including a new
bellows. I used to do camera repair full-time some years back and I was fond of
restoring some of the grand old cameras.
Go to your local Tandy leather store and pick up a nice thin skiver. A skiver
(sp?) is a split sheep skin -- it's thin and pliable. Next get some black shoe
dye -- the liquid type, and a good quality contact cement. The last ingrediant
you'll need is a sheer fabric -- I go to the fabric store and buy some of the
synthetic stuff they use to back window curtins.
Use a pencil to draw the folds of the bellows onto the outside of the leather.
Use an existing bellows as a model. (Leave some excess leather to trim later.
Coat the inside of the leather with the contact cement and adhere the fabric to
the leather. This will provide the stiffness needed so that the bellows will
hold its shape. When the cement is dry -- use the shoe dye to throughly dye the
inside of the leather/fabric black. When the dye is dry you can start folding.
Use large paper clips to hold the corners together as you fold and crease.
Eventually the bellows will want to take its own shape.
Use the contact cement to seam the bellows together and finally dye the outside
whatever color you like -- I like red. With good care you'll have a bellows
that will last a lifetime.
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Holler if you need more help.
Joe Angert
St. Louis Community College
[email protected]
================================================================================
Note 27.13 -< Kodak's Ultra Fast and Ultra Grainy Recording Film >-------------------------------------------------------------------------------> I'd enjoy hearing any tips you'd like to share about Kodak's Recording Film.
> I've used it off and on for two or three years. The film's beautiful grain
> structure is unlike any other. When it's gone, it'll be a great, if
> little appreciated, loss.
I've never understood why the only grain that seems to be sought is "fine"
grain. Grain is, after all, a part of this medium, and in itself,
potentially a factor in the aesthetic vocabulary.
Recording film is IMHO the absolute film of choice for night photography.
Used with pyrocatechin compensating developer, it is possible to maintain
superb shadow content and at the same time, contain the light sources.
Since the film has no anti halation backing, there is halation but the
light sources remain distinct. It is the only film/developer combination
that I have really found adequate for night clubs, stage performances
without additional lighting, street dances, you name it -- any condition
which is basically a very low ambient light with extreme hot contrasts in
the million to one plus range.
Typically, I rate the film at 800 ISO (the data recommended for the film,
IMHO, explains why no one uses it -- everybody tried it once, found it ugly
and hated it, and never tried it again!). I usually take an incident
reading in a generalized area lit by whatever ambient light is there,
deliberately excluding the highlight areas (which is where everyone else
seems to want to meter). In a typical Seattle street scene, this would
give me about 1/15 - 1/30 at f/2.8 - 4. This means, if it is a band on
stage playing under changing lights, I would pretty much ignore the changes
and go for the shadow illumination for my exposure. This certainly
simplifies the decisions I have to make.
The developer is the typical formula from Windisch, available in many
sources:
Solution A:
Water ......... 100ml
Pyrocatechin...
8 g.
Sodium Sulphite
1.25 g.
Solution B:
10 percent caustic soda
(though it is generally not recommended to use household chemicals in such
formulas, I've had absolutely consistent results for years with Red Devil Lye).
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Solution A will keep for quite a long time in stoppered dark bottles;
Solution B is best renewed every week or so.
For use, take 12 parts solution A, 7 parts B, 500 parts water.
Be aware that pyrocatechin is listed as a probable carcinogen, so gloves
are in order, as are precautions against breathing the dust when mixing.
Pyrocatechin tans the emulsion, and toughens it. The film will turn into a
corkscrew when it dries. Reverse rolling it for a day or so takes care of
that.
This will produce a fair amount of fog (BROWN FOG, BROWN IMAGE). To
minimize this, I develop at 65 degrees fahrenheit, using a stainless steel
tank with one fewer reel than the tank is designed for. I agitate constantly
for 10 minutes. The theory here is that the fog will develop at the same
rate regardless, so by accellerating the highlight development through
constant agitation, my image to fog ratio is improved. Be sure, though,
that the air is removed, because oxygenating the solution will destroy any
gains you may obtain using this method.
Printing these images works best on graded papers, because they are so
brown that they act as a graduated low contrast filter on MG emulsions.
That is, the shadows may appear normal or even contrasty; the highlights
become progressively flatter the brighter they ought to be. This can
sometimes be used to advantage in extreme situations, but normally just
looks a bit strange.
I used this method for many years as a regular part of my work as a travel
photographer for _Sunset_ magazine here on the West coast. More of my
night images seemed to get into print than just about anyone else's.
This regime is great for night, but produces rather uninteresting images
under normal conditions.
Oh yes.... Back in the seventies, I used to develop it in Rodinal for 15 20 minutes at 50:1, I think. The resultant grain, with the image enlarged
directly on lith film, eliminated the need for halftone screens when making
silkscreen prints and photo-etchings.
Probably ought to end this here. But, I also have worked out information
for this film with MCM100, a true paraphenylinediamine fine-grain
developer. The grain is not fine, but it's verrrry Beauuuutiful! Well
worth the ISO 400 required. Much nicer than tri-x. Twenty minutes ought
to do it, but I don't have my notes handy. Write if interested. Have to
check my files. Now that I have got it down, the film goes out of print.
If it were possible to raise a hue and cry and save this film from
perdition, I'd sure like to do it. ALL of my favorite films seem to be
destined for doom.... I loved Royal X pan, Super XX.
Note 28.1
-< Lost Film Leader Retriever - Making Improvised One >-------------------------------------------------------------------------------Making a film retriever to use when you need to retrieve film
file:///C|/faq.html (228 of 555) [7/19/2002 3:46:27 AM]
that you have rewound completely back into its casette
Basically the concept is that you cut the sprocket hole areas in such a manner
that you generate a "sharkskin"-like edke to the film. The idea is that these
"barbs" slide easily into the casette but which engage in the sprocket holes
of the film inside the casette when pulled out. Below is a basic illustration:
_____________________________________________________________________________
| __
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|__|
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this is a piece of regular scrap film!
|
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| __
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|_____________________________________________________________________________
this is what you make out of the film above!
_____________________________________________________________________________
/ __
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\. | |
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| |_____\|__|
|_____\|__|
|_____\|__|
|_____\|__|
|_____\|__|
|__|
|
|
^
|
|
|
bend "barbs" _down_ towards emulsion side
|
insert
notice then they will slide into casette
| <--- this end into casette
easily but on way back will catch sprocket
|
first
holes
|
|
|
V
| _________
_________
_________
_________
______ __
__
| |
./| |
|
./| |
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./| |
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|__|
\_____________________________________________________________________________
You can usually just use one piece of this sharksin film and stick it as much
as will go into the casette. Then wind the core until you feel resistance.
Then pull it out and the film may come out with it.
Or, use two pieces of film, one plain with no sharskin pattern cut into it and
the other which is modified as shown above. Insert a length of plain film as
far as it will go into the casette ( usually it will only make one turn inside
the casetten and get stopped by the felt. Then insert the modified film "under"
the plain one and proceed as above. The function of the _plain_ piece is to
smooth out the inside of the casette so the leader will not have a chance to
file:///C|/faq.html (229 of 555) [7/19/2002 3:46:27 AM]
get caught on the felt light trap's edge.
andy, [email protected]
...............................................................................
> Does anyone have a convenient method for retrieving the tail end of film
> after it has been wound into the canister?
Sure! You'll need a scrap of film about 6" long (any unwanted 35mm film will do)
and a 3" (or so) strip of double-sided cellophane tape.
First, trim the corners of the film scrap so it'll slide into the cassette more
easily. You don't need to trim much - just round or clip the tip of each corner:
/--------------| O O O O O O O
|
|
|
| O O O O O O O
\--------------Next, turn the film over so the emulsion side is up, and apply the tape
along the lower edge starting from the right end. Remove the backing from
the tape so its other glue surface is exposed:
-------------\
O O O O O O |
|
TTTTTTTTTTTT|
TTTTTTTTTTTT|
O O O O O O |
-------------/
view from emulsion side -place double-stick tape in
area marked "TTT"
Now turn the film base-side-up and insert the taped end gently into
the cassette with the tape facing inward. Stop when you have a couple of
inches of film inserted. Rotate the projecting end of the cassette spool
clockwise several turns, as if to wind the film into the cassette, then
counter-clockwise until it jams, then clockwise again until you feel
resistance. Now *gently* pull the film out of the cassette; the leader
should be stuck to the tape and should come out. If not, just repeat
this procedure until it does.
I've had much better results from this type of homemade retriever than
from any of the commercial devices, and have never had any trouble with
scratching or bent light traps. The price is right, too! Hope this helps!
from:
Richard Hosker
[email protected]
Co-owner of the new Photo-L
<[email protected]>
:
:
:
:
Tennessee Technological University
Cookeville, TN
"Mama, don't take my Kodachrome away!"
............................................................................
file:///C|/faq.html (230 of 555) [7/19/2002 3:46:27 AM]
Here's one for you. Take a strip, maybe five inches long, from those
lettering label guns and peel off the backing. Feed the strip into to
"tongue" side of the cannister. Then tighten the tension of the spool
until you feel the film catch onto the inserted strip. Make sure its stuck
on there firmly. Then slowly pull out the strip and the "tongue" of the
film should come out with. It may take a few tries, but it works.
Stan Kaady, [email protected]
================================================================================
Note 28.2
-< Using Camera Meter to determine Foot Candles >------------------------------------------------------------------------------->Can somebody tell me how I can measure footcandles using my camera's light
>meter?
Here is a rough way to do this ...
Get an 18% grey card. Set your film speed to ISO 125. Set your shutter speed
to 1/125 second. Make a meter reading using standard care to avoid glare and
casting shadows.
If you were out in broad daylight and no clouds (sunny 16 conditions) you would
be under 6400 foot candles if the camera suggested an aperture of f:16. If the
camera suggests f:11, you are under 3200 foot candles, etc. as follows:
f:32
f:22
f:16
f:11
f: 8
F:5.6
f: 4
F:2.8
f: 2
f:1.4
25,600
12,800
6400
3200
1600
800
400
200
100
50
If you change your shutter speed to 1 second then at f:16
candles and the progression would go like this:
f:32
f:22
f:16
f:11
f: 8
f:5.6
F: 4
f:2.8
F: 2
f:1.4
you'd find 50 foot
200
100
50
25
12
6.25
3.12
1.55
.80
.40
All of this is based on the fact that we "know" that the sunny 16 condition is
set up for approximately 6400 foot candles and that then the following
relationship holds true for correct exposure assuming no RLF.
file:///C|/faq.html (231 of 555) [7/19/2002 3:46:27 AM]
Foot candles =
25
times f# squared
--------------------------ISO times exposure time
for example you see you'd get 6400 if
25 is a "constant"
sometimes 20 is used
(calibration suggested)
25 x 16 x 16
---------------125 x 1/125
corrections most welcome!
Andrew Davidhazy, at RIT's Imaging and Photo Tech Dept, [email protected]
================================================================================
Note 28.3
-< Reloading Unreloadable Cassettes with Bulk Film >------------------------------------------------------------------------------->When reloading bulk film currently I'm using these cassettes that make me
>real nervous. I've noticed that the caps appear to be always in danger of
>popping or falling off ... yikes! Is there someone that would recommend one
>cassette over the other for those that roll their own film.?
I almost hesitate to mention this again 'cause it is a pet procedure of mine
but I have found that the best reusable cassettes are the supposedly
unreloadable ones the manufacturers put their film in.
I either use ones I've saved myself or ask for them at a local photofinisher.
When I unload them I pull the film out of the cassette (most photofinishers do
the same) and cut the film away from the cassette leaving a "stub" about 3/4
inches long protruding from the cassette.
To reload the cassette I slip a piece new film under the stub and into the
cassette and affix the two with this 3M translucent tape. This piece only joins
the backs of the two pieces of film but runs the width of the film. The basis
on which I do this is that the shear strength of the tape "connection" is very
great.
Since I reload the kind of film into the cassettes that they held in the first
place the DX code on the cassettes works properly. The film is also secure from
accidental falls on hard floors, etc.
Andy Davidhazy, at RIT's Imaging and Photo Tech Dept, [email protected]
================================================================================
Note 28.4
-< Circular vs. Linear Polarizers - more scoop >------------------------------------------------------------------------------->What is the difference between linear vs circular polarizing filters?
Linear polarizers can be made to "interfere" and thus remove linearly polarized
light such as that caused by glare off non metallic surfaces. At the same time
the linear polarizer imparts "linear" polarization to the light rays that pass
through it.
If you place a second linear polarizer behind the first one you can arrange
file:///C|/faq.html (232 of 555) [7/19/2002 3:46:27 AM]
their orientation so that most of the light arriving to the first one is
extinguished by the second one.
Circular polarizers can do the same but the light that leaves them is not
polarized. This is because it consists of two "devices" sandwiched together.
The first, located closest to the subject or source of glare, is a plain linear
polarizer. Behind it, closer to the camera lens, is an optical retarder whose
function is to make the exiting light circularly polarized basically meaning
that the exiting light rays are not polarized.
If you place a linear polarizer behind a circular polarizer you will find you
can not diminish the intensity of the light rays by turning one with respect to
the other (which you can do with two linear polarizers "in series").
OTOH if you place the linear one in front of the circular one then the familiar
"variable density" effect will be exhibited.
It is interesting to note that a linear polarizer can be turned around and
perform its function of eliminating glare regardless of which side is facing
the subject. A circular polarizer _must_ be used in the correct orientation for
it to work.
Andrew Davidhazy, at RIT's Imaging and Photo Tech Dept.
----------------------------------------------------------------------------->What is the difference between linear vs circular polarizing filters?
This may be more than you wanted to know, but here it is anyhow:
Light always has a polarization direction, crossways to the direction
it's travelling. You can think of it as being like arrows flying
sideways, where the tip of each arrow is pointing in the polarization
direction. (Actually, for this discussion, the arrows have tips on
both ends.) For most light, the polarization direction is constantly
changing in a random way, and we call it unpolarized light. When more
of the arrows point one way than another, we call the light polarized.
The _strength_ of polarization can vary - maybe there is only a slight
excess of arrows pointing in some one direction, or maybe all of them
point the same.
Most of the things you take pictures of are emitting (or reflecting,
or scattering) _unpolarized_ light towards the camera. But some things
give polarized light. Reflections from water, glass, and many other
surfaces are partially polarized. Skylight is polarized, with varying
strengths depending on angle from the Sun.
A linear polarizer allows light that's polarized in it's
characteristic direction to pass through. Light that's polarized
crossways to the polarizer's direction is absorbed. And light that's
polarized in between is partially passed and partially absorbed. The
part that passes through is weaker, but is now polarized in the
polarizer's direction.
Linear polarizers are used to eliminate the parts of the light that
are polarized in some direction. So you can, for example, eliminate
file:///C|/faq.html (233 of 555) [7/19/2002 3:46:27 AM]
the reflections from a pool of water, or darken the sky, by using a
polarizer.
So where do circular polarizers come in? Modern SLRs, by and large,
use components that are sensitive to polarization in both the light
metering system and the autofocus system. So if you're using a
polarizer to modify the photograph, you may wind up confusing the
camera. The solution is to use a circular polarizer. This is a
sandwich consisting of first, a linear polarizer, and second, a
quarter-wave plate. The linear polarizer does all the good stuff you
want a polarizer for in the first place, but the light coming out of
it is polarized. This doesn't matter to the _film_, but will confuse
the camera body. The 1/4 wave plate solves this problem. It is able to
take those arrows that are coming out of the linear polarizer, and
start them spinning, so their tips move in circles. That way, the
camera's internal systems get light that, _on average_ is polarized in
every direction equally, and for the camera's purpose this is
equivalent to unpolarized light.
Circular polarizers are more expensive than linear ones because they
have to include both the linear polarizer and the quarter-wave plate.
William Tyler
[email protected]
================================================================================
Note 28.5
-< Depth of Field - a formula approach >------------------------------------------------------------------------------->Does any one have a formula for depth of field based on Focal length of lens,
>film format and f-stop? I was out shooting this weekend in a stand of pines
>and the combination of deep shade and overcast sky made it impossible to see
>much on the ground glass when the lens was stopped down. With the above info
>I could make a spread sheet and carry a print while shooting.
A method of calculating the nearest and farthest point in focus is:
Nearest point=UxFsquared/[(Uxcxf)+Fsquared]
Farthest point=UxFsquared/[(Uxcxf)-Fsquared]
where
U = subject distance in mm
F = focal length of lens (mm)
c = circle of confusion (assumed to be 0.036mm for a 35mm neg
enlarged to 8x10)
f = aperture
This gives you an answer in mm - if you subtract the nearest point in
focus from the farthest point in focus you will get the depth of field.
I hope that you can understand the way I have typed the above formulae.
"x" = multiply and "Fsquared" = FxF.
I haven't used this method myself but it comes from a great little pocket
handbook called "The Professional Guide to Photo Data" by Richard Platt
(Mitchell Beazley 1991)
file:///C|/faq.html (234 of 555) [7/19/2002 3:46:27 AM]
from: Guy Newcomb, Brisbane, Australia, ([email protected])
================================================================================
Note 28.6
-< pointer on better photographs of nudes >-------------------------------------------------------------------------------Tips on Making Better Nudes
Frank Wallis
I have several suggestions for better images, or at least some things
to think about. Before I do that, I recommend devouring as many books
on the subject as possible, and not "how to" books, but monographs and
anthologies of nudes.
Here are some things to try:
1) try torso shots in closer, with the model's arms raised
2) move around the model's torso, or have her/him turn 1/4 turns,
in order to find the most pleasing view. Finding pleasing
views is one of my favorite activities.
3) move in closer, or use a longer lens, to fill the frame with
fascinating, interesting, pleasing forms
4) for 3/4 or full body shots, move the model at least six feet
from the backdrop. We want to see the model, not the backdrop.
5) try props, which can be anything really (flowers, whips, balls)
6) try articles of clothing; dressing or undressing
7) try "drapery": gauze, fishnets, sheets, etc. (although I rarely
see effective use of this, and "drapery" usually comes off
shopworn and even silly).
8) try a theme and attempt to make a portfolio based on this theme:
such themes can sound absurdly simple sometimes, but photogs
such as Christian Vogt have used sticks, bathrooms, posing
blocks, hats, masks, etc.
9) try two models; woman/woman, man/woman, etc.
10) tie models up with rope, chains, scarves (with their permission!)
11) explore the graphic possibilities of fetish gear, e.g., latex,
rubber, leather, high heels
12) cast patterned shadows upon the model by employing screens of
various shapes and designs, placed between the light source and
model. This can be done with natural or artificial light.
13) use natural light; place the model near a window, or pose them
outside if conditions permit. I've had models pose nude on the
streets of Manhattan, but you must not assume the police will
look the other way if they observe such an event.
14) try different lenses, filters
15) if you find a model you like working with then work with her/him
a dozen times if you wish. Who said you need to have a hundred
different models? Let Playboy Studios operate the factory.
16) your model doesn't have to smile, but if you really want a smile
I hope you have a quick wit.
17) no grinning allowed. It looks like your model is holding back.
Tell her/him to relax the mouth, jaw, lips, etc. Of course, if
you are concentrating on a torso or body fragment, then the
facial expression is irrelevant.
18) try different printing techniques on the same negative
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19) have the model sign a release and try to get your work published.
What good will your creativity do if civilization is denied the
opportunity to learn from it and appreciate it?
Hope this has been of some use.
Frank Wallis, <[email protected]>
================================================================================
Note 28.7
-< Exposure Correction in Enlarging >------------------------------------------------------------------------------->i would like to know if there is any formula for darkroom enlargement. for
>instance, 8x10 b&w printing required f8 and 15sec. what would it be for 11x14?
Yes there is. The correction you need to make assuming you already know what
the correct time is at a given sized enlargement is as follows:
Take the new dimension and divide it by the old dimension and then square that
number. This gives you factor by which the exposure needs to be changed.
You can then either change the exposure time or the aperture to match the
desired factor. However, keep in mind that papers are susceptible to
failing to follow the reciprocity law and you may need to fine tune any changes
you make in exposure time to allow for this.
For example:
to go from 8x10 made at f8 and 15 sec. to 11x14 you do this:
11 divided by 8 equals about 1.4
1.4 squared is equal to 2 therefore you
need to open up the lens to 5.6 and keep the exposure time at 15 seconds or
keep the aperture at f8 and change the time to 30 seconds. But probably you'd
change to something like 35 seconds to allow for RLF.
to go to a 4x5 from the same 8x10 you'd do this:
4 divided by 8 is equal to .5
.5 times .5 equals .25 therefore you need
1/4 of the original exposure which you get by stopping the lens down to f:16 or
cutting the time down to about 4 seconds.
Andy Davidhazy
[email protected]
================================================================================
Note 28.8
-< Pinholes, f#s and proper exposure Determination >------------------------------------------------------------------------------->I am making a pinhole camera and I have calculated my f#'s to be these with
>various distances between my pinhole and the film ... making a zoom pinhole.
>Pinhole dia. (mm)
Film-hole dist (mm)
f/
>0.15
10
67
>0.15
15
100
>0.15
20
133
>0.15
30
200
>0.4
60
150
>0.4
80
200
file:///C|/faq.html (236 of 555) [7/19/2002 3:46:28 AM]
>0.4
100
250
>0.4
120
300
>0.4
200
500
>How would I use the reciprocal rule to calculate the exposure time on polaroid
>film if my meter said f/16 at 1/250 second??
It is not clear what you mean by the reciprocal rule. If you simply want to
find out what the exposure time would be at a "new" (pinhole) f# given the
exposure time at f:16 then you do this.
new f# divided by old f# squared multiplied by old exposure time = new time
for example:
32
64
128
256
16
16
16
16
1/250
1/250
1/250
1/250
1/60
16/250 or 1/15
64/250 or 1/4
256/250 or 1
now this is likely to lead to underexposure due to the fact that Polaroid
materials exhibit significant failure in responding appropriately to the
Reciprocity Law. This states that "exposure" remains constant if an increase
in exposure time is matched by a corresponding decrease in aperture. Well,
photographic materials do not produce the same _density_ as one changes the
components that make up exposure.
So, for materials that exhibit long exposure time "reciprocity failure" one
must add _extra_ exposure to achieve a particular density. This can be done
most effectively by increasing the aperture (impractical in your case) or
increasing the time. The factor by which the time component needs to be
increased given a particular starting time varies from emulsion to emulsion.
Actually for Polaroid Type 55 film it seems that the adjustment with either
aperture or time given a starting exposure time of 10 seconds is +1/3 stop or
+3 seconds. At a 1 second starting time the film exhibits no reciprocity
failure according to a Polaroid Data sheet I am reading.
i am not sure if any of this is "on target" ...
Andrew Davidhazy, at RIT's Imaging and Photo Tech Dept., [email protected]
================================================================================
Note 28.9
-< Optimum Pinhole Diameter - Further Suggestions >-------------------------------------------------------------------------------I have done some research into correct size of pinhole for a given image
plane distance.
The optimum pinhole diameter is a tradeoff between 'geometric' resolution
and 'diffractive' resolution. The former is the fact that the minimum
'pixel' size is equal to the pinhole diameter (thus smaller being better)
and the latter is the fact that the resolution of any optical system is
proportional to its aperture (thus larger is better).
For those that don't want to read further, the formula is
file:///C|/faq.html (237 of 555) [7/19/2002 3:46:28 AM]
d = squareroot( 1.22 L w )
where d is the pinhole diameter, L is the distance from pinhole to
image plane, and w is the wavelength of light. The units don't matter
so long as you are consistent. E.g., in millimetres, w = 0.0005mm.
If L = 250mm, then d = 0.38mm. The f/ratio is
f = L / d
which is f/645 in this example.
Now for the details... The above formula is based on the summation
of formulas for the angular resolution for geometric and diffractive
considerations. This is bound to be on the conservative side. In
practise, the image should have better resolution than this, but
don't count on it.
The formula for angular resolution (geometric) is
phi = d / L
which is based on to point sources being resolvable if their image
circles do not overlap. phi is the minimum resolvable angular
separation of two point sources (in radians).
For diffractive resolution,
phi = 1.22 w / d
which is based on the Raleigh criterion.
Summing these formulae gives
phi = 1.22 w / d
+
d / L
which gives an optimum (minimum) phi when d = sqrt( 1.22 L w ). This
information was largely obtained from 'Optics' by Hecht and Zajac,
Addison Wesley press.
Regards,
Stephen J Hardy,
Canberra, Australia
[email protected]
================================================================================
Note 28.10
-< Painting with Light basics >-------------------------------------------------------------------------------> I do not have a problem determining the exposure for night time pictures,
> but I am a little confused on how to determine the exposure time or rather
> flash output when playing around with adding light bursts to different
> parts of a night time scene. This is an activity that I am doing wiht my
> high school students for a fun photoclub activity. I can't even remember
> what I have done in the past, but I know that the results were not
> consistent. Does anybody have any suggestions?
file:///C|/faq.html (238 of 555) [7/19/2002 3:46:28 AM]
Two simple suggestions to determine the correct flash exposure.
1) Use the guide number of the flash and divide it by the f-stop you are
exposing the night shot by and that will give you the distance in feet
(as long as the guide number rating is for feet also). If you then want
to make it brighter or dimmer you can either move closer or further or
use power ratio.
2) Simply take a flash meter reading and change the distance until you
get the f-stop to match the f-stop used for the night exposure. Shutter
speed will not play a part as long as you are slower than the synch speed.
I assume in night photography that will always be the case.
David Litschel
Brooks Institute
[email protected]
================================================================================
Note 28.11
-< IR _BLOCKING_ filters - what/where/why? >------------------------------------------------------------------------------->>I'm doing a camera project and I need some help with an IR filter.
>>I need a filter that blocks IR and passes visible light. Ideally,
>>it would fit on a C-mount camera lens (often used on closed circuit
>>TV cameras). Hoya makes a material called CM-500, which is billed
>>as a Cyan color compensating filter, that would work fine. But,
>>I can't find anyone who sells this stuff. Apparently it is not part
>>of their normal photographic filter line. Does anyone know of such
>>an IR filter, or of a supplier for the Hoya CM-500 material?
>Depending on the quality of the filter and wavelengths to be eliminated you
>could try a heat absorbing glass from a slide projector. Some of these are
>pretty good short wave IR blockers (and some are not so good).
>Otherwise you could try making a "liquid filter" with a solution of Copper
>Sulfate (the liquid will have a cyanish-greenish look to it).
>Or, you could contact Corning Corporation or Pittsburgh Glass (I think) and see
>what they have available as either rough stock or polished material. This is
>the expensive solution.
>from: andrew davidhazy, [email protected]
I am not disputing any of the above just adding to it. I think what you may
need is what is known as a HOT MIRROR, or infrared cuttoff filter.
Heat
absorbing glass removes some infrared by absorbtion but the transition from
visible to IR is gradual not a sharp cut so you will still get some near IR
transmitted. A hot mirror is an interference type filter which reflects the
IR (in the region 700 to 1000 nm) but transmits the visible to about 650nm
with a fairly sharp transition. My 1978 Kodak Filters Catalog lists the type
301A filter which is of this type. The Oriel Optics Catalog also lists
filters of this type as do other suppliers of laboratory optical components.
In the Kodak carousel slide projector there is such an
interference type filter with a sharp transition which appears to cut off at
about 700nm. I expect that cold mirrors would only be available
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as square glass types.
As for the hoya material check the IR transmission curves first as all dyed
filters I have come across transmitt freely in the near IR, even ND filters.
from: [email protected] (DESMOND J MCMILLAN)
================================================================================
Note 28.12
-< Underwater Dome Ports - a mathematical approach >-------------------------------------------------------------------------------Mathematical Characterization of Underwater Dome Ports
You can get more insight into dome optics by doing a little quantitative
analysis. Most books on optics contain at least one chapter on thick
lenses. In particular, chapter 5 in "Fundamentals of Optics" by Jenkins
and White has some general formulas which are directly applicable to
a concentric spherical dome lens. In the following, I assume a left to
right arrangement of water/dome/air with respective indices of refraction
n/np/npp. The dome's external surface (on the left) has radius r1, the
internal surface has radius r2, and the thickness of the dome is d=r1-r2.
For an object to the left of the dome, the following 15 lines of Fortran
code will compute the position and size of the image.
(all variables declared real)
f1=n*(r1/(np-n))
!primary focal length of dome's external surface
f1p=f1*np/n
!secondary focal length of dome's external surface
f2p=np*(r2/(npp-np)) !primary focal length of dome's internal surface
f2pp=f2p*npp/np
!secondary focal length of dome's internal surface
enovrf=np/f1p + npp/f2pp - (d/f1p)*(npp/f2pp)
f=n/enovrf
!primary focal length of the dome
fpp=f*npp/n
!secondary focal length of the dome
a1f=-f*(1.-d/f2p)
!position of the dome's primary focal plane relative
!to the dome's external vertex (on the dome axis)
a2fpp=fpp*(1.-d/f1p) !position of the dome's secondary focal plane relative
!to the dome's internal vertex (on the dome axis)
a1h=f*d/f2p
!position of the dome's primary principal plane relative
!to the dome's external vertex (on the dome axis)
a2hpp=-fpp*d/f1p
!position of the dome's primary principal plane relative
!to the dome's internal vertex (on the dome axis)
s=p+a1h
!p=object distance relative to external vertex
!s=object distance relative to primary principal plane
spp=npp/(n/f - n/s) !image distance relative to secondary principal plane
ppp=spp+a2hpp+d
!image distance relative to external vertex
mag=abs(spp/s)
!size of image relative to size of object
(These equations assume paraxial rays, i.e. rays making small angles with the
dome axis). If you substitute some reasonable values for the indices of
refraction and dome radii, you will find:
- the dome focal lengths are both negative, indicating a diverging lens
- the image distance "ppp" is negative, indicating that the image is to
the LEFT of the dome, and therefore the image is VIRTUAL
- the virtual image is always upright and always smaller the the object
file:///C|/faq.html (240 of 555) [7/19/2002 3:46:28 AM]
Consider an example:
n=1.33 (fresh water), np=1.5 (glass), npp=1.0 (air)
r1=3.0 inches (a 3-inch dome), r2=2.5 inches (half-inch thick)
The secondary focal plane, where objects at infinity have their images
(apparently) focussed is 6.53 inches to the left of the dome's external
vertex. An object 6 inches from the dome is imaged at 2.3 inches from
the dome with a magnification ratio of 0.44. And so on.
If the primary principal plane of the camera lens is positioned at the center
of curvature of the dome, which I think is approximately the case by design,
then the distance of the virtual image from "the lens" is (for this example)
6.53+r1=9.53 inches. "Twice the diameter" is 4*r1=12 inches, which is in the
ballpark. The rule of thumb obviously depends on camera placement and lens
construction.
By playing around with the various input variables you will also discover
that:
- increasing the index of refraction of the water (e.g. going from less saline
to more saline) brings the secondary focal plane closer to the dome. You expec
t
this, since horizontal rays striking the front surface of the dome follow
shallower entry paths into the dome, and end up diverging more at the dome/air
interface
- increasing the index of refraction of the dome also brings the secondary
focal plane closer to the dome, because of the enhanced bending at the
dome's rear surface
Consider all of the above as just a theoretical exercise on my part. I have
NO practical experience with dome ports, so if anything I've said is incorrect,
please let me (and everyone else !) know.
Les Wilk
From: [email protected] (Leslie Wilk)
... as seen on the Underwater Photography Mail list
================================================================================
Note 28.13
-< Catadioptric Lenses - brief description >------------------------------------------------------------------------------->Has anyone ever used a reflecting lens. I dont know exactly what they are
>called but they resemble a Newtonian telescope. They have no refracting
>elements in them and consist of a parabolic reflector with a flat mirror that
>bounces the image through a hole in the parabolic reflector into the camera
>body. I have heard that they only have one aperture setting and are single
>focal length. Also I have heard that they provide some interesting effects
>(aberrations) outside the focused depth of field.
These lenses are called catadioptric. They are not Newtonian (which
deflects the converging cone of light at right angles) and they DO have at
least one refractive element which also acts as a window to prevent dust
getting into the optics.
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'Cat' lenses for cameras are mostly based on the Schmidt-Cassegrain or
Maksutov designs. In both cases, the concave mirror is the primary optical
element which reflects and focuses light towards a smaller convex
secondary, which is placed ahead of the focal point of the primary mirror.
The secondary mirror deflects the light back through a relatively small
hole in the centre of the primary, and hence to the film plane. At the
same time, the secondary acts to increase the effective focal length, thus
allowing for a compact, long focal length design.
Aperture is usually fixed at about f/8 because of the mechanical difficulty
of fitting an aperture stop at the optically 'correct' point.
Aberrations as such are no worse than normal lenses, and in fact the
chromatic aberration can be made much smaller. The worst objection to cat
lenses is the doughnut-shaped out-of-focus highlights, which are basically
the shadow cast by the secondary mirror. This is not an aberration,
strictly speaking, but does annoy most photographers.
(I remember reading somewhere that there is some sort of sea creature
[perhaps a squid] which has a catadioptric eye. Presumably these squid
would not have such strong objections to the little doughnuts :-)
A Schmidt camera, in its simplest form, is a special telescope which has
practically zero aberrations over a large angle of view, which it achieves
with a simple spherical primary! Don't expect to find one in your local
camera store because you typically have to use single plates at a time, and
the plate needs to be spherically curved. Not only that, this is a prime
focus device, meaning that the film actually sits near the top of the
'scope, looking backwards at the mirror.
Regards,
Stephen James Hardy
Canberra, Australia
[email protected] (Steve Hardy)
================================================================================
Note 28.14
-< Tintype Parlor - tintype materials suppliers >------------------------------------------------------------------------------->I've been trying to find resources, instructions, and chemical lists/mixing
>instructions/cookbooks for making tintype prints. The only resources I've
>found are too general to be of any practical use. Any literature that might
>be of use is out of print or unobtainable. Any one have any instructions for
>this type of photographic work? And if any step-by-step directions exist,
>where would one find the chemicals?
I don't know whether this is precisely what you're looking for, but you may
still find this of use. There is a commercial product called Tintype Parlor
sold by a photographic store in Los Angeles. This information that I'm
providing is from their September 1993 catalog, so this information may not
be accurate.
Freestyle
5124 Sunset Blvd.
file:///C|/faq.html (242 of 555) [7/19/2002 3:46:28 AM]
Los Angeles, CA
(213) 660-3460
90027
Tintype Parlor
You can make authentic looking tintypes just like the
old masters. The kit comes complete with 5-4x5 tin
plates, coating emulsion, developer, and fixer.
183-2016
$ 24.95
from: John Oshiro, [email protected]
================================================================================
Note 28.15
-< Adhering Liquid Light to Glass >-------------------------------------------------------------------------------USE OF SUBBING SOLUTION WITH LIQUID LIGHT
A "subbing" solution is superior to varnish and paint for adhering
Liquid Light emulsion to glass or glazed ceramics. It consists of
a thin coat of hardened gelatin which penetrates the microscopic
pores of these materials and acts as a strong and permanent bond
for the emulsion.
First, the material to be coated (the substrate) must be made
chemically clean. Soak the substrate in hot water containing sodium
carbonate, then scrub with a cloth. Sodium carbonate is also known
as sal soda or washing soda (not baking soda) and is available in
many groceries. Arm and Hammer powdered laundry detergent is sal
soda and can also be used; do not use detergents or soap.
Rinse well after scrubbing, and observe how the water flows off the
surface of the substrate. It should form a barely visible film, and
not make droplets or bead up. If necessary, continue the scrubbing
until the surface is chemically clean.
Obtain some powdered gelatin such as Knox brand from the grocery
store. Sprinkle 1 level teaspoon of gelatin onto the surface of 1
pint (500 cc's) of cool water. Allow it to stand 15 minutes, then
dissolve the gelatin by heating on the stove.
Before use, add 10 drops of the enclosed chrome alum hardener per
ounce (30 cc's) of the warm gelatin solution. Pour this solution,
still warm, over the clean glass surface, drain thoroughly and
allow it to dry at least 4 hours or overnight. Then coat with
Liquid Light emulsion.
In addition to glass and glazed ceramics, the subbing technique can
be used to improve adhesion with materials that are slightly
porous, such as eggshells (after de-waxing with paint thinner),
rocks, seashells, fired enamels, etc. Do not use on highly-porous
materials like paper and cloth (no preparation needed) or
completely non-porous materials like metal or plastic (use oilbased varnish or paint).
Rockland Colloid Corp
P.O. Box 376
Piermont, NY 10968
file:///C|/faq.html (243 of 555) [7/19/2002 3:46:28 AM]
(Rockland sells a small amount of hardener by mail for $1)
================================================================================
Note 28.16
-< Pro School Photographers Association info >------------------------------------------------------------------------------->I am looking for a contact for what used to be called the Professional School
>Photographers of America. Can you help ?
PSPA is located at 3000 Picture Place, Jackson, Michigan 49201 517-788-8100
they are comprised of about 300 members and are a section of PMA International
andy, [email protected]
================================================================================
Note 28.17
-< ISO, DIN and ASA speed relationships >------------------------------------------------------------------------------->I am a little confused by all the different film speed ratings I have seen.
>Does anyone know of any mathematical relationships between ASA, ISO, DIN
>and any others that you may have seen??
ASA and DIN speeds are determined the same way .... except that DIN is a
logarithmic expression while ASA is an arithmentic one. The ISO speed of
a material is actually "ASA/DIN" (not divided by but ASA and DIN) but
we in the US tend to use only the arithmetic portion of the pair.
the DIN number is equal to 10 times log ISO + 1
and the ASA number is equal to antilog of (DIN - 1
eg:
ISO 200
DIN 23
divided by 10)
log 200 equals 2.3 times 10 = 23 + 1 = 24
24 - 1 = 23 / 10 = 2.3 and antilog 23 = 200
DIN
ASA
ASA speed is defined as .8 /log of exposure required to produce a density
of .1 plus base plus fog while meeting certain other criteria
DIN speed is defined as log of 1/exposure required to produce a density
of .1 plus base plus fog while meeting certain other criteria
Because the ASA speed number starts off with .8 rather than 1 an adjustment of
1 in the DIN side needs to be introduced to make the two match in the exposure
(given in mcs) required to deliver .1 above B+F.
In the ASA system a doubling of speed corresponds to a doubling in the
value of the speed number. In the DIN system a doubling in speed is indicated
by an increase in the speed number of 3. This is associated with the log of 2
(_double_ the speed) multiplied by 10.
I am sure that another ways of approaching/explaining this are possible.
From: Andy Davidhazy, [email protected]
and ......................................................................
ASA and ISO use the same system; each one-stop increase in the film speed
corresponds to a doubling of the speed rating. Hence, an ISO 200 film is
file:///C|/faq.html (244 of 555) [7/19/2002 3:46:28 AM]
one stop faster than an ISO 100 film, and an ISO 400 film is two stops
faster than an ISO 100 film. There are also intermediate ratings; an ISO
64 film is two-thirds of a stop slower than an ISO 100 film, and
one-third of a stop faster than an ISO 50 film.
The DIN system was developed in Germany, and has largely been usperseded
by ISO. In the DIN system, each one-stop increase in speed adds 3 to the
speed rating. An ISO 100 film has a DIN rating of 21 degrees; an ISO 200
film has a DIN rating of 24 degrees; and so on.
There's also a Soviet/Eastern European system known as GOST, but I'm not
familiar with its details. (Perhaps someone who owns a Kiev can help
fill this in?)
Note 29.1
-< Where to process Infrared Color Film >------------------------------------------------------------------------------->>Anyone know who develops color infrared film? Seems near impossible to get
>>it done anywhere.
try:
Rocky Mountain Film Lab
145 Madison Street
Denver, CO 80206
303-399-6444
or
Johns Hopkins School of Medicine
Raymond Lund, RBP, FBPA
Monumnet and Wolf Streets
Baltimore, MD 21205
301-955-3843
maybe also,
Precision Photo Laboratories
5758 N. Webster Street
Dayton, OH 45414
513-898-7450
University of Guelph Illustration Svcs.
Guelph
Ontario, N1G 2W1, CANADA
519-824-4120 ext 3641
American Photo Group
616 Dwight Street
Springfield, MA 01103
413-739-2521
Buffalo General Hospital Photo Dept.
100 High Street
Buffalo, NY 14230
716-845-2863 (call before sending film)
Kolor Print Inc.
2121 Thayer Street,
Box 747-72203
Little Rock, AR 72202
501-375-5581
Lightwork Labs
509 NW 10th Avenue
Gainesville, FL 32601
904-376-9745
from: andrew davidhazy, [email protected]
================================================================================
Note 29.2
-< 3D Processing and Finishing Laboratories >------------------------------------------------------------------------------->Where does one send film exposed in a Nishika or Nimslo camera for
>processing?
To have film developed and printed into 3D lenticular prints there are at
least two labs that will do it. They also do "custom" work and may be
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willing to print stereo "pairs" into 3D prints. They make enlargemets also.
Nishika makes prints that include 4 images while Image-Tech makes ones that
rely only on three images. (If they print Nimslo material one of the images
is left out).
Nishika Laboratories
1 Nishika Drive
Henderson, NV 89014
702-435-7000
or
Image-Tech Laboratories
5172-G Brook Hollow Parkway
Norcross, GA 30071
404-416-8848
from: andy davidhazy, [email protected]
================================================================================
Note 29.3
-< Star Trail Control with Exposure Time >------------------------------------------------------------------------------->I photographed the Orion stars last week and one of the pics had star trails
>rather than star spot. What is the maximum time allowable to prevent the stars
>from trailing? I used a 200mm lens pointing it about 30 degrees from zenith.
This is an interesting question since while the angular speed of the stars is
the same, roughly 15 degrees per hour, their effective speed on the film varies
with elevation. I do not have the answer but am going to try figuring it out.
Suppose the camera is aimed low to the horizon then the lens will record an
angle in the sky equal to its angle of coverage. For a 50 mm lens horizontally
this is about 40 degrees, a 100 20 degrees and a 200 10 degrees. The stars
appear to move at 15 degrees per hour or 15/60 or .25 degrees per minute or
.25/60 or .0042 degrees per second. So, using a 50mm lens, a star's image will
move across the frame in 40 degrees /.0042 degrees per second = 9600 seconds
So how many star images are there in 40 mm? at 100 stars per mm there would be
roughly 4,000 so in one second you'd have to "cover" about 1/2 stars worth.
If your criterion says that you have to restrict motion to a "blob" one star
tall by four or five stars long then you'd have to have a maximum exposure
time of 8 seconds. Exposure times longer than about 10 seconds will already
show significant trailing. Ultimately it really depends on how much blur you
can allow. If you can only allow motion equivalent to one star's image diameter
on the film your exposure time requirements will be much more stringent than if
you can allow the star's image to move two, three or more diameters before you
consider it a trail instead of a spot.
Now if you raise the angle of the camera towards the poles then the effective
speed of the images will be less ... or another way to say it is that you will
cover more "degrees" of the sky with the same lens. Essentially with the camera
pointed at the pole star you will cover 360 degrees around the pole star (with
any lens!) and there will be very little motion at all in this region and much
longer exposures can be tolerated.
Anyway, this means that you can probably use longer and longer times as the
elevation of the stars approaches the pole stars. If your stars are within 30
degrees of the pole star you can probably roughly double or maybe even
quadruple the time you'd use at 90 degrees to the pole star.
I'm going to assume a linear relationship between image velocity and focal
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length and thus if for a 50 mm lens at the celestial equator I need to use a
time 8 seconds with a 50 then in the same region I'd need to use 4 seconds
with a 100 and 2 seconds with a 200.
Tilting the camera towards the pole star may allow a time let's say 4 times as
long so for a 50mm lens that would be 24 seconds, a 100mm lens 12 seconds and
for a 200mm lens it would be about 6 seconds.
Please note that I am placing this here more as a point of discussion rather
than as an absolute and correct answer to the question posed by Magnus above.
andy, [email protected], at RIT's High Speed Photography Lab
============================================================================
From: [email protected] (Ben A. Fairbank)
Subject: Re: Star Trails
Organization: University of Texas at San Antonio
An earlier poster, message deleted inadvertantly, asked about the exposure time
necessary to avoid star "trails" when making star photographs. He or she
mentioned that he/she was shooting about 30 degrees from the zenith.
The answer depends on a number of factors; rather than posting an answer that
might be wrong for the case you are interested in, let me explain one way to
figure your own answer, at least as a starting point. You can use the answer
you calculate as an approximation and make test shots starting there. First,
the distance from the zenith (straight up) of your picture is not relevant
unless you also give your latitude and the direction you are shooting. Even
then the calculation is nontrivial. The really important figure is how far
from the north celestial pole you are shooting.
Let us calculate for the worst case -- that for stars on the celestial equator
(worst because they will always move the fastest, regardless of how far they
are from the zenith). Start from the final product -- the prints you will
make. How big will they be? Eleven by fourteen? OK, now, since all star
pictures made with a camera that does not follow the stars will be tracks, not
points, what is the longest track that is acceptable to you in your 11 x 14
prints? One millimeter, you say. Okay, now slate that to your negative. Let
us assume, again for simplicity, that you are using a 35 mm camera and printing
the full frame. That means you will be enlarging about ten times so that the
longest star track that is acceptable on the negative is 0.1 mm. It is now
necessary to translate that into an angular measurement -- a measurement of how
far across the sky, in degrees or minutes of angle, the star moves during your
exposure. You specified a 200 mm lens, so we can calculate the tangent
(remember from your trig that the tangent is the opposite side divided by the
adjacent side of the triangle as "seen" by the angle of interest) of the angle
as being (0.1/200), which is 0.0005. (Purists: I know that this involves a
slight simplification, but it agrees with the true value to seven significant
figures...) Now find the arctangent of 0.0005, which is 0.0286 degrees, or 1.7
minutes of angle. The problem now is to find how long it takes for the
celestial sphere to rotate 1.7 minutes of angle. The earth rotates 360 degrees
in 24 hours or 15 degrees per hour or 1 degree in 4 minutes or 1 degree in 240
seconds, or sixty minutes of ANGLE in 240 seconds of time or 1 minute of ANGLE
in 4 seconds of time (all equivalent rates). Thus it would take about 7
seconds for the sphere to rotate 1.7 minutes of angle.
file:///C|/faq.html (247 of 555) [7/19/2002 3:46:28 AM]
Therefore, if you want your star trails to be one millimeter or less in length
in an 11 by 14 print from a 35mm negative taken with a 200 mm lens you should
expose no more than 7 seconds on the celestial equator. You can modify the
prodecure depending on your requirements, but the general method will remain
the same.
================================================================================
From: [email protected] (Ben A. Fairbank)
Subject: Re: Star Tracks (again)
Organization: University of Texas at San Antonio
This is a shorter but more practical version of my earlier post in in answer to
the question of how long one may expose pictures of stars in order for the
stars to appear as points, not lines.
The star images will
so the question will
finished print?" If
the exposure time is
involved:
always be lines if the camera does not follow the stars,
always be "How long a line can you tolerate in the
you know how long a line you can tolerate, then figuring
straightforward. The following five variables are
E = degree of Enlargement (for example, enlarging a 35 mm negative
to an 8x10 print involves an E factor of 8) planned for final
print of the negative
L = Length of longest permissible star track in final print (this is
measured in millimeters)
F = Focal length of taking lens (again, measured in millimeters)
D = angular Distance from celestial equator to the star in the
photo which will be nearest the equator (this is known as
the star's declination)
T = maximum exposure Time which will guarantee that the tracks will
be no longer than L.
The formula is
T = 240 * Arctan (L / (E * F)) / (Cos D)
If, as is often the case, you do not know the value of D, then just ignore the
division by Cos D. This will have the effect of giving the exposure time
appropriate for stars on the equator, which are the fastest-moving of all
stars. Any off-equator stars will move more slowly and so will make tracks
even shorter than your maximum acceptable length.
Examples:
If you are making a 4 by 6 print of a picture taken with a 50 mm lens on 35 mm
film, with the closest star to the equator being 40 degrees from the equator
and a maximum permissible star trail length of 1 mm, then your maximum
exposure would be 90 seconds.
file:///C|/faq.html (248 of 555) [7/19/2002 3:46:28 AM]
If you were making an 11 by 14 enlargement of a 35 mm negative taken with a
200 mm lens of stars on the celestial equator and could tolerate a 1 mm trail
length, then your maximum exposure would be about 6 seconds.
DISCLAIMER -- This equation was derived from simple geometric and astronomical
princples, but since I am not an astronomer (except an amateur one), it may
still be wrong. See article by James V. Bradley entitled "Overconfidence in
Ignorant Experts."
Ben Fairbank.
================================================================================
and from Michael Gudzinowicz:
Estimating the length of a star trail is fairly simple. First calculate
the rate of angular motion... 24 hr/day X 60 = 1440 minutes X 60 sec =
86400 sec; 360 deg / 86400 sec = 0.00417 deg/sec. One can include a factor
for the position of a star in relation to the axis of rotation... let A be
the angle between the pole star and the star of interest. Then the
angular rate approximates (sin A)*(0.00417) deg/sec.
For small angles, the tangent and sine are very nearly proportional to the
angle, so one may substitute the rate of change of the tangent of the
angle swept by the earth's rotation, giving rate tan/sec = (sin
A)*(0.0000727)/sec.
The tangent of the angle is the film_streak_length /
during time = T,
focal_length. So
streak_length/focal_length = T * (sin A)*(0.0000727)/sec or
T = film_streak_length / ((focal_length)*(sin A)*(0.0000727).
(Close approximation).
If one wishes to make a "sharp" 8X enlargement from 35 mm, the circle of
confusion (0.03 mm) can be substituted for the streak_length. Using a 100
mm lens, 90 deg from the pole star, the maximum exposure time is
approximately 4.1 seconds. For longer lenses or larger prints, the time is
shorter. For wider lenses or angles closer to the axis of rotation,
exposure times can be longer.
With the pole star in the frame for long exposures, it is apparent that
trails form arcs with the star at the approximate center. The arc angle
increases at the rate of 15 deg per hour... a 90 deg arc requires a 6 hr
exposure (use films with high reciprocity failure to prevent sky fog).
(Note that a number of assumptions were made in determining the rate of
motion on the film plane, but the errors introduced are relatively small
considering the intended purpose of the calculation.)
-Mike in RI / Internet: [email protected]
[email protected]
.............................................................................
and here is yet another contribution to determining star-trail and
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exposure time relationship:
length of star trail on the film:
l_film = 7.3 x 10^-5 * focal length in mm * exp time in sec * cos(declination)
where declination is of course 0 at the celestial equator and +/- 90 deg
at the celestial poles. Zenith angle doesn't matter.
Compare to conventional choice of say 0.03 mm as acceptable circle of
confusion for 35mm format. (Any good lens will do better than 0.03 mm
I would imagine.)
That number, 7.3 x 10^-5, is from 15 arcsec per second of time (earth's
rotation) and 206265 arcsec in one radian, if anyone cares.
From: Ben Weiner, [email protected] at Rutgers University
..............................................................................
and another:
I finally found the right book:
Skyshooting: Hunting the Stars with your Camera
R.N. Mayall & M.L. Mayall, 1949
New York, The Ronald Press Company
The length of any star trail is found by the formula on page 17:
T = 2pi * F * (t / N), where:
T =
2pi
F =
t =
N =
length of trail of an equatorial star
= 6.28
focl length of the lense
exposure time (in seconds, minutes, or hours)
number of seconds, minutes or hours in one day
1 day = 24 hours = 1440 minutes = 86400 seconds
If my math is correct, a star trail of 0.1 mm length (which will look like a
dot) requires a maximum of 10.2 seconds on a 135mm lense and 27.5 seconds on
a 50 mm lens.
Of course, the film speed, the **seeing** and the f/stop will determine
how bright each dot will be (how many stars, or how faint a star, will be
recorded).
Fred Gunther, <[email protected]>
================================================================================
Note 29.4
-< Problem with Glass Carriers and Rings on Prints >------------------------------------------------------------------------------->Sometimes when printing negatives with a glass carrier I notice faint rings
>of density spread all over my prints. I have noticed this also in my Leitz
>Focomat enlarger where the condenser comes in contact with the film. Why?
The problem is caused by Newton's rings, a light interference effect that
shows up when two very smooth surfaces come in close proximity to each other
causing light rays to constructively or destructively interfere with each
file:///C|/faq.html (250 of 555) [7/19/2002 3:46:28 AM]
other. Where there is constructive interference you will perceive a dark band
on your print and a lighter, underexposed, band where there is destructive
interference.
The problem can be overcome to some extent by spreading anti-newton powder
between the offending surfaces or using glass that has a slightly roughened
surface. This is regularly used by makers of glass slide mounts. The powder
can be obtained at Graphic Arts suppliers. I have never used it myself.
To overcome this problem in your enlarger use anti-newton glass in the carrier
or add an anti-newton glass spacer below the Focomat's condenser. There is a
likelihood that the pattern etched into the anti-newton glass may show up as a
faint texture in your prints however.
For small film sizes you might simply use anti-newton glass from a slide mount.
For larger sizes Condit Mfg. Company sells anti-newton glass in various sizes.
They not only sell anti-newton glass but also pin-registartion equipment useful
for special-effects work. They are at: Condit Mfg. Co. Inc., 29 Philo Curtis
Rd., Sandy Hook, CT 06482, (203) 426-4119 (Warren L. Condit is the President)
================================================================================
Note 29.5
-< Black Light >------------------------------------------------------------------------------->Pardon my ignorance but I am a self taught/teaching novice. What is a black
>light? What is it used for in general? With exposure of approx1/4sec, what
>aperture was used? I'm interested in learning and experimenting.
Black light is the colloquial term for Ultraviolet rays (as opposed to
"light" rays which we can see). UV is energy of shorter wavelength than
reds, greens or blues. UV is invisible but some sources such as used in
concert admission validation stations are almost visible. They are called
"long wave" UV sources. There is also short wave UV which is dangerous to
your health and is responsible for the tanning effect of sunlight.
The term "black light"is often associated with illuminating a subject with
"black" (invisible or nearly so) light and viewing its transformation by
certain substances to longer wavelength rays which are relatively easily
visible. This effect is called fluorescence. Fluorescence can appear as
light of various colors depending on the "transformation" quality of the
material illuminated by the UV. It is best perceived when there is very
little light present.
Since under these conditions the eye's pupils are wide open and the
retina's effective "speed" is increased to a maximum, even small levels of
fluorescence (which is typically the case) are easily seen ... but are
relatively difficult to photograph. Thus typically there is a need for
large lens apertures and fast films. Apertures of maybe f:2, film speeds
in the 400 ISO range and exposure times in the 1 to 1/8 second range using
fluorescent tubes emitting mostly long wave UV "light". Since the power of
these tubes is hardly standardized it is really difficult to give
definitive exposure guidelines.
A good place to see dramatic color effects caused by UV excited
fluorescence is your local science museum in the minerals division. If you
are photographing this phenomenon it is best to use a slight yellow filter
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such as a Wratten 2E because this will prevent the UV rays from causing un
"unnatural" bluish cast on your color films. The 2E filter should be used
even though to the eye the colors are not contaminated by excess blue.
This is because the eye is not affected by the presence of UV being
insensitive to it but color films may respond to the excess UV present
(even though some films have a UV blocking filter layer coated as the top
layer on the emulsion.
If you are interested in further reading on this subject you could check
out the articles available from the following address: [email protected]
andy
o o 0 0 o
o Andrew Davidhazy, at RIT's Imaging and Photo Tech Dept
\/\/\/\/\/\/
[email protected]
High Speed Photography Lab
________|
|__________________________________________________________
================================================================================
Note 29.6
-< Minox Cameras Dated and Described >-------------------------------------------------------------------------------Minox Subminiature Camera Models List (1.1)
Authors: Bennett Todd <[email protected]>
Bob Salomon <[email protected]>
This is a preliminary draft. I'd appreciate corrections and additions. I figure
this might be helpful to people considering buying a used submini, or just
curious about their history. Anyone seriously interested in Minox subminis
should definitely buy and read "Spycamera -- the Minox Story", by Morris
Moses (1990, Hove Foto Books, ISBN 0-906447-43-7). While I didn't copy this
out of Moses or anything, I definitely learned more from that book than from
everything else put together.
If I get enough positive feedback (including additions and corrections!) may
try to shove this into the FAQ repository.
All Minox subminis are viewfinder cameras with a fixed-focal-length 15mm
lens, which has a similar FOV on the 8x11mm negative to a 50mm lens on a 35mm
camera. Except for the EC, all are manual focus (8" to infinity) f/3.5. The
EC's lens is fixed-focus (six feet to infinity) f/5.6. They all take the same
film cartridge, a daylight-loading affair, still available. Minox now has
Ektar 25, whose resolution helps make up for the small negative format. All
except the EC focus down to 8", and have parallax-corrected viewfinders for the
close-focusing. Besides uses for document duplicating, this is handy for other
macro shots. For instance, a Minox submini makes a _great_ camera to take to an
orchid show.
The models:
Original "Riga": stainless-steel case. Original lens; not as sharp near the
edges of the frame as later lenses. This is the only stainless-steel bodied
model; it's the heaviest, and the least-likely to be dinged. Highly-prized
collector's item; tends to go for >$2,000. Made in Riga, Latvia.
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Minox II: like all post-WWII Minoxes, aluminum-bodied. Made in Wetzlar,
Germany. Different lens design from Riga; rear element of lens actually
touches film surface, leading to problems with scratching.
Minox III: new lens design, essentially the same as all later Minoxes (except
the EC), called the "complan". Still completely manual with no meter; this
and later models are all fine shooters.
Minox IIIs: just like the III, with a flash synch (PC connector).
Minox B: First Minox bigger than all the previous. This one is a bit longer,
and adds a selenium cell light meter. You still set the shutter speed by
hand.
Minox C: still longer than the B; this one is the biggest Minox submini; where
a IIIs is about 3-1/4" including PC flash connector, the C is about 4-1/2"
long. This is the first Minox submini with Auto-Exposure; it has a CdS cell
light meter, which can control the shutter speed (which can also be manually
set). You _can't_ tell what speed the meter is gonna use. This is the first
Minox submini to require a battery.
Later models of C, as well as the LX, have a modified complan lens, changed
to focus on a flat plane rather than a curved one. So, they have a flat
pressure plate. The best prints are made if you use an enlarger with a flat
or curved film holder to match the flat or curved pressure plate in your
camera.
Minox LX: current manufacture; shorter than the C (but larger than the
originals); auto-exposure, as well as manual. The first Minox whose shutter
speed goes up to 1/2000.
Minox EC: also current, this is targetted as a mass-market point-and-shoot,
with a fixed-focus lens that focuses 6 feet to infinity.
Somewhere in these last few models (I'm not sure where) the Minox factory moved
from Wetzlar to Giesen, Germany.
-Bennett
[email protected]
================================================================================
Note 29.7
-< Filter Primer >-------------------------------------------------------------------------------FILTERS: The Basics
Peter Bryenton, (C) February 1995 (except for personal use).
Filters work by changing light into heat as energy passes through
them.
The idea of a filter is simple enough. If you go down to your
favourite burger bar and place an order, you'll get what it shows
on the menu photograph. If you don't want everything that way,
you just ask for something to be changed - usually customers
want an item left out. Suppose you don't like mayonnaise. It is
easy to say "Please don't put any mayonnaise on my burger" if
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you are in England. In America I guess that shouting "hold the
mayo" probably gets the same result, which is a burger which
has been made specially to order.
So it is with the filters used in photgraphy. There is a starting
point, which is made up of the filter itself and the light source
which must pass through it. What comes out is light which has
been modifed by the filter. Something you did not want in the
light has been taken away (subtracted).
A blue filter (one that looks blue when you hold it up to your
eye) takes part of the incoming light energy away by changing it
into heat on its way through. The bits it removes are the colours
we see as greens and reds. When our eye-brain systems see red
and green light mixed together we get the impression of yellow
light.
(All the colours you see on your TV set are really coming to
your eye from just three sets of tiny dots of light which are red,
green and blue. Check this out with a magnifying glass).
A blue filter is sometimes called a "minus yellow" filter to show
its action more clearly. In black and white photography, using a
panchromatic emulsion ("pan" film) means that the film records
all the visible colours of the spectrum (look at a rainbow to see
them). The film "sees" everything, though not necessarily exactly
the way we do.
WORKING IN BLACK AND WHITE
If you want your final monochrome print to show an originally
blue sky as being darker in tone than it would be shown by the
straight film itself, you can take away some of the blue light in
the sky by placing a yellow filter over your lens at the taking
stage. This method works the other way round from the
explanation above; here the yellow filter works as a minus blue
filter and only lets the red and green through. Red and green are
seen by both pan films (like T-Max) and people as yellow and
that is exactly what the glass looks like to our eye.
Taking light away is the same as reducing the exposure in the
camera, (have you ever shot with a lens cap on ?) so you end up
with a darker (underexposed) sky. Because this filter allows
greens and reds through almost unchanged (nothing is perfect
and there will always be a slight loss), green grass and red
flowers in a landscape will get almost the same exposure they
would have done without the filter being used at all.
What making the right choice of filters can do for you is to give
you more control over different areas of the same image at the
taking stage. Used effectively, filters are a powerful tool in your
box of photographic spanners (wrenches). Maybe you want to try
this for yourself now and start thinking about why a red
safelight is essential for multigrade printing work but a yellow
one will do just fine for graded papers.
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SAFETY:
This light-to-heat effect explains why, in theatre lighting for
example, all those dark, deep moody colours burn out so quickly.
There is a lot of subtracting light going on and the heat has to go
somewhere - into the filter material itself. Thankfully the days of
them bursting into flames are over due to the modern
flame-proof plastic bases.
The average glass filter used in front of a camera lens never
meets this problem of course but some photographers like to
filter their tungsten lamps by covering them with gels. If you do
this, remember to leave plenty of room for ventilation and don't
leave them switched on unattended. Models spend a lot of
money on their hair and clothes especially for you. They like to
leave a session with everything they had when it started.
So, next time you eat a Big Mac, why not think about trying a
little creative filtering for your monochrome work? Lemons (the
fruit your bartender cuts up) and deep blue filters can be fun.
Peter Bryenton (C)
BBC Wood Norton, UK
================================================================================
Note 29.8
-< Is Photography a Language? >-------------------------------------------------------------------------------Is photography a language?
J. David Sapir
University of Virginia
Talk for Brown University
6 March 1995
copyright by J. David Sapir 1995
Photography can be called a language only if you say that any form of human
communication is a language - dance, music, painting, drawing or sculpture.
Note: William Crawford, in his Keepers of Light, picks up the concept of
syntax that was used by William Ivins in Prints and Visual Communication:
"conventions or systems of linear structure" used in the "preparation of a
drawn image." Here is a system of organization "used in putting lines together
to form pictures that can stand as representations of particular objects."
Although Ivins considered photography as having no 'syntax,' Crawford in
exploring the many forms of photographic processes that were used in the 19th
century disagrees. A Daguerreotype is distinct from a caleotype and the two
differ from wet plate callodion photographs.
Consider the frequently reprinted 19th century engraving from Germany (I
believe) a backpacker viewed from the back carrying his photographic
equipment. Crawford titles: 'Wet Plate photographer carrying his syntax on his
back.'
consider also the photo of: William Henry Jackson outside of his 'dark tent'
and William Henry Jackson's two assistants (a man and a mule).
Note: Alan Sukula mocked the idea of photography being a "universal
language", though he might accept it as a language.
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I don't find it terribly useful to call photography a language. Having at one
point worked out the grammar of an African language, I am hard pressed to see
any useful parallels and anyway would insist on trying to find irregular verbs
in photos, if photography was indeed a language.
The old distinction made by Susanne Langer in her 1940 Philosophy in a New
Key, is a good place to start. She talked of two types of symbolism (using
symbol in the broad sense, the way Peirce would use sign). Discursive and
Presentational. Quintessentially language is discursive: it is lineal, it is
atomistic and it is paraphrasable. That is: words are strung out, one after
the next. You don't get the idea until the sentence, or paragraph - chapter,
book is gone through. A sentence can be broken down into words and each word
carries meaning and can be put into a lexicon. And the sense of what is
communicated in language can be communicated by using different words, or a
different order to the words - here is the cat -> the cat is here -> voici le
chat. Now each point can be disputed, or greatly modified given particular
instances. For example poetry defies paraphrase - although you can explain it
- or try to explain it, a lot is lost, even beyond the disruption of what
Roman Jakobson called the 'poetic function,' the musicality of verbal sounds.
'If music be the food of love, play on, give me excess of it ... ' Try to
paraphrase that.
Presentational symbolism - the opposite: here everything together - at once it finds its 'meaning' from the entire gestalt. The relation ship of parts to
a whole - where the parts are themselves without meaning. The idea of
paraphrase does not apply. An image - a drawing, a painting, would be the
quintessential presentational symbol. There would, of course be exceptions.
For example a sequence of images in a set would imply a discourse.
Photography fits squarely with presentational symbols - on the other side
from language. So, at this initial point photography and language emphatically
part company, as they would in taxonomies more complex than that of Langer.
But if there is little point in talking of a photographic language, it becomes
very interesting when we ask ourselves how photography finds its place among
other presentational forms. What kind of image is a photograph? It is not,
primarily, an image at all. It is an index. This we learn from Charles Peirce.
Let me quote the one place where he speaks about photography:
Photographs, especially instantaneous photographs, are very instructive,
because we know that they are in certain respects exactly like the objects
they represent. But this resemblance is due to the photographs having been
produced under such circumstances that they were physically forced to
correspond point by point to nature. In that aspect, then, they belong to the
second class of signs [indices], those by physical connection. (Buchler,
1955:106).
I am not exactly sure when he wrote this paragraph, but I am sure it was after
the invention and broad distribution of the Kodak which was introduced in the
1880's.
It is the photograph's indexicality that determines its uniqueness. Hence, its
interest to semiotics. To deny or ignore a photograph's indexicality, its
trace (as Susan Sontag puts it), is to absorb it into the class of all
graphic forms - photography becomes one out of a repertoire of image
processes: engraving, lithography, woodcutting, painting, etc. This is
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precisely the position taken by commentators who come to photography from the
angle of art: that is, those art critics who have decided that photography is
an art. In fact, according to some of those critics, it is today's art of
choice.
Let us worry the idea of indexicality - and in our discussion we will want to
ask two separate questions: First: when is it important, in fact essential, to
take into account the indexicality of a photograph, and when not. Secondly,
why are art critics and art photographers disinclined to consider the
indexicality of a photograph. Or, if they consider it, they consider as
something of no great moment.
The importance of indexicality. We learned from James Frazer that there are
two types of magic: The magic of contagion; which is the magic of things that
are once together, are always together - you work on someone's finger nails or
hair clippings and you work on that person. And the magic of sympathy - things
that are similar to each other are the same. Thus, you burn in effigy the
image of someone you wish to harm. Images - pictures - participate in the
magic of sympathy. Photographs participate in both.
There are lots of stories about people who believe that a part of themselves
is taken away when they are photographed. These are said to be "primitive"
people. But not just socalled "primitives," back country hayseeds. John
Thomson experienced difficulties making his memorable photographs during his
travels in China in the 1870's. And that great primitive Honore/ de Balzac
thought as much. 'He had a theory .. that each time the shutter clicked a
layer was peeled off the personality of the sitter.' Nadar said of the theory:
'He had nothing to fear; his abdominal contours allowed plenty of latitude for
shedding ghosts.' [There is only a single known daguerreotype of Balzac, owned
at one time by Nadar and used by Rodin for his great sculpture of Balzac.]
Franz Boas gave this example to show the universality of "primitive thought:"
I take your photograph - today it would be very simple to take a polaroid Your image emerges, I take it, spit on it, crumple it up, toss to the floor
and stamp on it, all the while saying 'horrible picture, horrible picture.'
What is your reaction?
The double magic of a photograph - its indexicality coupled with its imaging presses upon us mainly in one specific variety of photograph: Photographs of
people and this would come up most particularly in family pictures and beyond
them to photographs of, what I like to call 'people in the world' ...
documentary photographs, photojournalism, street photographs, papparazzi
pictures. Throughout all, the photograph, at an important level, remains
attached to its referent. The referent is omnipresent.
This, of course, is what fascinated Roland Barthes in his last book, La
Chambre Claire. The link between the photograph and the subject leads him to a
dramatic discussion of the sinister nature of a photograph: a person is
present, but as the photograph was taken at a time in the past, the person is
no longer or, at least, is no longer in the situation and condition as appears
in the photograph. He or she might be dead. Thus he reflects on a photograph
of his mother when she was five years old - a young child full of the energy
of youth. But his mother is dead. Thus he talked of a photograph as
representing the living dead. In his dramatic rhetoric: Photographs are a form
of madness.
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It is the indexicality - the
that a photograph never lies
untruth of a photograph does
Lange (is said to have) said
lots of photographs.
contagion - of a photograph that leads us to say
- a picture is worth a thousand words. The
not rest with its indexicality. As Dorothea
'photographs don't lie, but lots of liars take
However - if there is an indexical and mechanical relationship between the
photograph and the subject of the photograph there is also, on the flip side,
a subjective choice, made by the photographer, to take a picture at a precise
moment and from a precise angle and in a precise light. So here we have a
photographer controlling the recording of a subject's trace. If a photograph
"maps" reality, then the contours of this reality will be chosen by the
photographic "operator."
But if the photographer controls the action of taking, the photographer at
the same time is never relieved of the actuality of his/her subject. This, of
course, has ethical implications, a fact that concerns serious
photojournalists, not to mention family shutterbugs and portrait
photographers. In taking a picture you owe something to your subject. If you
think otherwise, as does Richard Avedon, your photographs will surely come
back to haunt you.
What I say applies primarily - if not exclusively - to photographs of human
subjects especially of subjects that present themselves or are taken by the
photographer as photographs of themselves as they are or as they believe
themselves to be. A studio model, paid to comply, would have less involvement.
And of course these issues scarcely arise when the subject is non-human or
inanimate - a rock, a tree, a mountain, or a pepper. You photograph the
pepper, then you eat the pepper, as Edward Weston would do. Although the grand
photographs of the West taken in the latter decades of the 19th century by
Carleton Watkins, William Henry Jackson, Timothy O'Sullivan and others have an
indexical presence which even today is truely thrilling.
This brings us to the second topic to worry, the disinclination of an art
critic to take into account a photograph's indexicality.
We learn from Kant that an aesthetic entails a 'pleasure without concept,' and
thus is detached from any moral judgements and practical reason. This, of
course, gives us our 'art for art sake' and to the expressiveness of the
individual artist. From this angle, if a subject of a photograph maintains an
indexical claim to his or her image, then the artist photographer loses total
claim to the creative process.
[As an aside. It is fascinating to read - by report or often in how-to manuals
- about the subtle play, theatre really, that evolved between the great 19th
century portrait photographers and their subjects: Southworth and Hawes in
Boston, Nadar and Carjat in Paris, Julia Cameron, Hill and Adamson, Lewis
Carroll in England. We find this today in the Mann Family Theatre Company:
Sally the producer and director; Emmett, Jessie and Virginia the script
writers and actors.]
When the referent persists, resisting transcendence, the photographic work of
art becomes entailed, it is forever contingent. This will not do, and such a
relationship must be brushed aside or, more likely, simply ignored.
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Or - if an indexicality is admitted as part of the basic photographic process
- it is purposely obliterated. This is where 'art photography' seems mainly to
be at this moment. Many processes are available to relieve a photograph of any
recalcitrant ties to the world. There are forms of manipulation that have been
available for many years: combination photographs - photographs made up of
many separate photographs - complex processes that overlay a photograph with
various gums and sticky inks and other substances or by simply painting over a
photographic base. The possibilities are many.
But the top of the list and the most talked about is the manipulation of
photographic material by way of computer processing. The possibilities are
limitless and I shall not go into them for I am sure you are familiar with
what can be done. I will, however, mention the vocabulary that goes with
computer imaging: A photograph is taken - it is than digitized by scanning this is called 'image capturing,' the next step is 'image processing' here you
work upon the image within an application such as Photoshop. The final step
is image storing, either by filing to disk or by sending the image to a 'list
device' (lst) - a printer. Throughout any discussion of computer photography
the major focus is on the 'processing.' The original act of taking a
photograph is merely the procurement of an image to be processed. This is a
far cry from Edward Weston's belief that you should 'pre-visualize' the final
print in the ground glass of your camera. Or from Cartier-Bresson, who
considered the act of seeing and of taking the photograph as the essential
element, the realization of geometry in emotion at an instant in time. The
final photograph was of lesser moment. For Cartier-Bresson, an intense
engagement with the world was more important than what might come from it.
Our discussion brings up four variables which may be very briefly summarized
as follows:
Photography 1. A photography in the strict sense where the integrity of the
index is left in tact. I would like to call it, "straight photography,"
however the stylistic contrast between straight and pictorial photography
leads to confusion. Obviously, much of pictorial photography is straight in
the way I would want to use the word. Let me settle for an inelegant
'unmanipulated' photography.
Photography 2. A photography that obliterates, through manipulation, the
indexicality of the photograph. The manipulation destroys photography's
uniqueness.
Commentator 1. Commentators on photography who are sensitive to it
indexicality. They focus on the photograph in relationship to the world
revealed by the photograph - the historical context, issues of ethics and
power in the relationship of the photograph to and photographed. One topic
that rubs up into my field of anthropology is the representation of the
"other," especially during colonial expansion. The art of the photograph is
not addressed.
Commentator 2. Commentators on photography who see photography as an art form
and welcome the complex mixed media genres as harbinger of a regenerated
photography. The indexicality is belittled as a 'myth' or is simply ignored.
What is interesting is when the two types of commentary cross paths as they
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invariably do before a simple indexical photograph of a human subject. Let's
take a look at America's most celebrated person picture, Dorothea Lange's
'Migrant Mother.'
Commentator 1. will tell you immediately that we are talking about Florence
Thompson and her daughters Norma, Katherine & Rubby. What has become of them?
How did Lange approach the family when she came to take the picture? Where did
the photograph fit into the FSA project, what was the relationship of Lange to
the other photographers and they all to Roy Stryker and what was the
relationship of the FSA to ideology of the New Deal? How was the photograph
used then and how is it used now. And what prompted the creation of this
unique documentary archive and how did it end up in the library of Congress?
If commentator 1. looks at the set of six photographs Lange took he/she notes
that in one Florence Thompson has the start of a smile and in two others
there is a fourth child, an adolescent lounging in a rocker. The adolescent
has a far away look in her eyes. Is she dreaming about Clark Gable? By pulling
the one photograph out and forgetting the others can we infer that there is
some propaganda angle at play? These are just the beginning of the questions
to ask and explore!
Commentator 2. may perhaps dismiss the photograph as a 'shop worn' cliche (as
one critic I read referred to Brassai's Paris at Night photographs). But if
pressed Commentator 2. will talk of the emotion in the face, the iconography
of the madonna, and strong formal arrangement with the mother's arm bringing
our eye to her face. The children are present but bury their faces against
their mother. We know they are there, but we are not distracted from the
mother. If commentator 2. exams the set of six he/she will see the
progression of Lange's eye, step by step as she approaches her final pose the contact sheet as a page from a poetic sketch book, is the phrase. Beyond
the "migrant mother" photograph commentator 2. will want to place it in
Lange's other work at the time and compare it to what preceded the FSA time
and what came later.
How can I end? Can I imagine that these two conflicting commentators exist
simultaneously in the spirit of an any active and accomplished photographer of
people? They must, and perhaps the presence of commentator 1. explains why
photographers like Dorothea Lange resisted calling themselves artists.
-----------------------------------------------------------------------I concluded my talk by showing two sets of photographs. The first set stemmed
from the latter part of the discussion and consisted of a sample of
photographs I took during my field work in Africa. I'll post a set of them on
the WWW within a month. Regardless of their intrinsic merit they represent a
photographer's frame of mind.
Secondly, going back to the opening question of photography and language and
the kinds of communication each represents I ran photographs against a text.
Short excerpts from Lewis Carroll's Alice book were read while thrown up on
the screen were a set of Charles Dodgeson's child pictures. Do looking at the
pictures effect how we hear and understand the words was my query? Do they
make us think differently about Alice and her creator? Try it for yourself to
see. It is a lot of fun.
"The question is," said Alice, "whether you -can- make words mean so many
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different things."
"The question is," said Humpty Dumpty, "which is to be master - that's all."
J. David Sapir
Department of Anthropology
University of Virginia
Charlottesville, VA 22903
(804) 924-6821
[email protected]
http://fermi.clas.virginia.edu/~ds8s
"Fixing Shadows"
================================================================================
Note 29.9 -< Hundreds of Film/Developer Processing Instructions >-------------------------------------------------------------------------------Subject: FAQ: B&W Film/Developer combinations
From: [email protected] (Phil Herring)
(Last update: December 1994; some times for Tri-X added; times for
Ilford Delta films added. The list now contains 296 film/developer
combinations.)
B&W Film + Developer Combinations ------------------------------This list has been compiled from data sheets that I've accumulated over the
years, and shows the recommended processing times for a wide range of films
in a wide range of developers. For each, the recommended ASA rating is
listed; some are intended for push-processing. The recommended agitation
routine is also shown, along with an indication of the resulting negative
contrast, and the source of the information.
Old and/or obsolete films have been included. Beware: some of their
replacements have similar names but may have quite different processing
requirements.
Note that these times should be treated as starting points only. Processing
variables will mean that you will never be able to replicate the conditions
used by the manufacturers to produce their figures; besides, only you can
decide how you want your negatives to look.
All times are for 20 degrees C; that's 68 degrees F for those of you still
living in the dark ages. (Except for the time for Kodak TMZ from Kodak; the
figures shown are for 21 degrees C/70 degrees F.) 35mm format in a daylight
tank is assumed.
Disclaimer: I'm not responsible for any of this information. Errors
probably typos.
Thanks go to Andreas Wolpers ([email protected]) for
times for Ilford Delta films.
are
supplying the
If your favourite film/developer combination isn't here, feel free to mail
me the details for inclusion in future versions of this list. Be sure to
send times at 20 degrees C, and include the resulting film speed, the
intended agititation pattern, resulting contrast (i.e. whether it's intended
for a condenser or diffusion enlarger) and the source of your information.
For consistency, manufacturers' recommendations are preferable, but personal
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processing times will be included when
nothing else is available.
Film
----
Developer
---------
ASA
---
Agfa Ortho 25
Neutol NE
Neutol
Rodinal 1:10
Refinal
Atomal
Refinal
Rodinal 1:25
Rodinal 1:50
Rodinal Special
Studional 1:25
Atomal
Refinal
Rodinal 1:25
Rodinal 1:50
Rodinal Special
Studional 1:15
Atomal
Refinal
Rodinal 1:25
Rodinal Special
Rodinal 1:50
Studional 1:25
Atomal
Refinal
Rodinal 1:25
Rodinal 1:50
Rodinal Special
Studional 1:15
Atomal
Agfapan 25
Agfapan APX25
Agfapan 100
Agfapan APX100
Agfapan 400
Fuji Neopan 400
Fuji Neopan 1600
Min
---
Agit
----
Cont
----
Source
------
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
100
100
100
100
100
100
100
100
100
100
100
100
400
1600
Refinal
400
Rodinal 1:25
400
Rodinal 1:50
400
Rodinal Special 400
Studional 1:25 400
HC110 dil B
400
3
3
5
10
7
4
4
6
2.5
2.5
17
6
6
10
4
4
7
6
5
4.5
7.5
4.5
13
6
8
17
4
4
11
16
6
7
11
4.5
4.5
6
NA
NA
4
D
C
4
E
C
5
D
D
4
D
C
4
E
C
5
D
D
4
D
C
4
E
C
5
Rodinal 1:25
Rodinal 1:50
Microfine
T-Max
6
11
6
10
4.5
15
7.5
9
7
8.25
6.5
7
5.75
D
D
4
A
C
1
D-76
D-76 1:1
Microdol-X
HC-110 (Dil B)
Microphen
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400
400
400
3200
1600
3200
1600
1600
800
800
400
1600
3200
C
4
ID-11
SPD
SPD 1:1
Fujidol
Rodinal 1:25
Rodinal 1:50
Ilford Pan F
Ilford FP4
Ilford FP4+
Perceptol
Perceptol 1:1
Perceptol 1:3
ID-11
ID-11 1:1
ID-11 1:3
Microphen
Microphen 1:1
Microphen 1:3
Rodinal 1:25
Rodinal 1:50
Perceptol
Perceptol 1:1
Perceptol 1:3
ID-11
ID-11 1:1
ID-11 1:3
Microphen
Microphen 1:1
Microphen 1:3
Rodinal 1:25
Rodinal 1:50
Plus 1:9
Plus 1:19
Plus 1:29
Ilfosol S 1:9
ID-11
Microphen
Ilford HP5
Perceptol
Perceptol
Perceptol 1:1
Perceptol 1:3
ID-11
ID-11 1:1
ID-11 1:3
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1600
800
1600
3200
800
1600
1600
1600
1600
6.5
4.5
4.25
8
4.5
6.5
6.5
5
8
25
32
32
50
50
50
64
64
64
32
32
64
100
100
125
125
125
200
200
200
125
125
125
200
50
125
200
50
125
200
50
125
200
50
125
200
125
200
50
200
200
200
400
400
400
11
12.5
17
6
8.5
12.5
4.5
5.5
8.5
5
15
10
11
16
6.5
9
15
5
8
11
9
18
3
4
4.5
6
8.5
6
8
12
3.5
4
5
5
6
8
5.6
6.5
7.5
11
14
21
7.5
12
21
D
D
4
B
C
2
D
D
4
B
C
2
D
D
4
B
C
2
B
C
2
Ilford HP5+
Microphen
Microphen 1:1
Microphen 1:3
Rodinal 1:25
Rodinal 1:50
HC-11O "B"
500
500
500
400
400
800
400
6
11
22
6
9
8
7
Perceptol
Perceptol 1:1
Perceptol 1:3
ID-11
400
400
400
400
800
1600
400
800
400
500
800
1600
3200
400
800
400
400
800
1600
3200
400
800
1600
400
400
800
1600
3200
400
800
1600
400
800
1600
3200
400
800
1600
400
400
800
1600
400
800
400
800
1600
11
15
25
7.5
10.5
14
13
16.5
20
6.5
8
11
16
12
15
23
3.5
5
7.5
11
6.5
9.5
14
9
3.5
5
7.5
11
6.5
9.5
14
3.5
5
7.5
11
6.5
9.5
14
9
7
8.5
14
9.5
14
7.5
9.5
12.5
ID-11 1:1
ID-11 1:3
Microphen
Microphen 1:1
Microphen 1:3
Plus 1:9
Plus 1:19
Plus 1:29
Ilfotec HC 1:15
Ilfotec HC 1:31
I'tec LC29 1:9
I'tec LC29 1:19
I'tec LC29 1:29
Ilfosol S 1:9
Ilfosol S 1:14
D-76
file:///C|/faq.html (264 of 555) [7/19/2002 3:46:28 AM]
E
C
5
C
2
C
C
B
T-Max 1:4
Acufine
Rodinal 1:25
Rodinal 1:25
400
800
1600
3200
400
800
1600
400
800
400
6.5
8
9.5
11.5
4.5
6.5
9.5
6
8
8
D
D
4
Ilford Delta 100
ID-11
50
100
200
Microphen
100
200
Perceptol
50
100
I'tec HC 1:31
50
100
I'tec LC29 1:19 50
100
Ilfosol 1:9
50
100
D-76
50
100
200
T-Max 1:4
100
200
Acufine
100
200
Rodinal 1:25
50
100
200
6
B
C
2
7
11
8
12
10
15
4.5
5.5
4.5
5.5
3.5
5
6
7
11
6
8
3.5
5
4 **NR poss uneven development
7
NR
Ilford Delta 400
ID-11
5.5
7
9.5
5.5
8
10.5
13
6
7
9.5
6
7
9.5
4.5
7
10.5
5.5
7
9.5
5.5
200
400
800
Microphen
400
800
Perceptol
200
400
I'tec HC 1:31
200
400
800
I'tec LC29 1:19 200
400
800
Ilfosol 1:9
200
400
800
D-76
200
400
800
T-Max 1:4
400
file:///C|/faq.html (265 of 555) [7/19/2002 3:46:28 AM]
B
C
2
Acufine
Rodinal 1:25
Rodinal 1:50
Kodak Tech Pan
Kodak Panatomic-X
Kodak Plus-X pan
Kodak Tri-X pan
Technidol LC
Dektol
D-19
D-19 1:2
HC-110 (Dil B)
D-76
HC-110 (Dil F)
Perceptol
Perceptol 1:1
Perceptol 1:3
D-76
Microdol-X
HC-110 Dil. B
ID-11
ID-11 1:1
ID-11 1:3
Microphen
Microphen 1:1
Microphen 1:3
Rodinal 1:25
Rodinal 1:50
Perceptol
Perceptol 1:1
Perceptol 1:3
ID-11
ID-11 1:1
ID-11 1:3
Microphen
Microphen 1:1
Microphen 1:3
Rodinal 1:25
Rodinal 1:50
Perceptol
Perceptol 1:1
Perceptol 1:3
ID-11
ID-11 1:1
ID-11 1:3
Microphen
Microphen 1:1
Microphen 1:3
T-Max
T-Max RS
file:///C|/faq.html (266 of 555) [7/19/2002 3:46:28 AM]
400
800
400
800
200
400
800
200
400
800
1600
16-25
200
100-200
100-160
100-250
64-125
32-64
25
32
32
32
32
32
32
32
32
64
64
64
32
32
64
64
64
125
125
125
200
200
200
125
125
320
320
320
400
400
400
500
500
500
400
400
7
9
4.5
6
6
7
10.5
12
16.5
NR
NR
5-11
3
2-8
4-7
4-12
6-12
6-12
7
8.5
9
5
7
4.25
5
7
12
5.5
7.5
13.5
5
11
8
8.5
12
6
8
13
6
8.5
13.5
6
13
10
12
15
8
11
9
6
11
22
6
6
F
3
B
C-D
H1
H2
H3
H4
H5
H6
C
D
D
4
B
C
2
D
D
4
B
C
2
C
C
3
2
HC-110 (Dil B)
D-76
D-76 1:1
Microdol
Rodinal 1:25
Rodinal 1:50
D-76
HC-110 (Dil B)
D-19
T-Max
D-76
D-76 1:1
HC-110 (Dil B)
Microdol-X
Rodinal 1:25
Rodinal 1:50
T-Max
D-76
D-76 1:1
HC-110 (Dil B)
Microdol-X
Rodinal 1:25
Rodinal 1:50
T-Max
Kodak HS IR
Kodak TMX
Kodak TMY
Kodak TMZ
Rodinal 1:25
Rodinal 1:50
Rodinal 1:25
400
400
400
400
400
400
NA
NA
NA
100
100
100
100
100
100
100
400
400
400
400
400
400
400
800
1600
3200
6400
12500
1600
3200
6400
1600
3200
6400
3200
3200
?
7.5
8
10
10
7
16
11
6
6
8
9
12
7
13.5
5.5
12
7
8
12.5
6
10.5
5
10
7.5
8.0
11
13
15.5
10.5
13.5
16
7.5
10
12
8
16
4.5
Rodinal 1:50
?
10
Konicadol DP
D-76
Konicadol Fine
DK-20
Konicadol Super
ID-66
32
32
32
32
32
32
6
6
7
7
6
6
D-76
HC-110 (Dil B)
Kodak Recording 2475
4
Konica IR 750
D
D
4
C
NA
3
C
C
3
D
D
4
C
C
3
D
D
4
C
C
3
D
D
4
D
D
A
C
Agitation
---------
6
A
B
C
D
E
Cont.
Cont.
Cont.
Cont.
Cont.
for
for
for
for
for
first minute, then five seconds each minute
first 10 seconds, then ten seconds each minute
60 seconds, then five seconds every 30 secs.
first minute, then every 30 secsonds
30 seconds, then five seconds every 30 seconds
file:///C|/faq.html (267 of 555) [7/19/2002 3:46:28 AM]
F
Shake tank 10 times rapidly for 2 seconds every 30 seconds.
Contrast
-------C
D
H1
H2
H3
H4
H5
H6
Condenser enlarger
Diffusion enlarger
CI = 2.50
CI = 2.25-2.55
CI = 2.40-2.70
CI = 1.20-2.10
CI = 1.10-2.10
CI = 0.80-0.95
Official Sources
---------------1
2
3
4
6
Fuji Photo Film Co., Ltd.
Ilford Limited
Eastman Kodak Company
Agfa-Gavaert
Konica Corporation
Note 30.1
-< Making Masks to Make Money w/ Trading Cards >------------------------------------------------------------------------------->Anyway my idea is this, Print out the text and symbols for whatever masks
>I'd like to create using standard White Paper and a Laserjet printer. Then
>using a Copy stand and Kodalith Film make a mask which I can then sandwich
>with a negative and print as usual. Seems like a GREAT way to make Trading
>Cards for Little League teams and such. So am I completely DAFT or is this
>a feaseable idea? What speed is Kodalith available in? How difficult to
>process is it?
You can start your exposure tests at ISO 8 under tungsten lights, with the
film processed in Kodalith developer, and ISO 25 processed in D-11.
Sheet film processing can be done in trays, and can be done under a red
safelight (Kodak 1a), so you can see a little of what you are doing.
Agitation should be continuous and development time is 2.75 minutes for
Kodalith developer and 2.5 minutes for D-11. Make your trial exposure
readings from an 18-percent gray card.
If you are shooting the 35mm film, you can load the film on reels and then
agitate continuously in the tank for the same times.
Consider creating your computer artwork at the largest size your printer
can produce (so a trading card would fill as much of a letter size page as
possible, for example), include black boxes where the photo will go (to
create a transparent "window" on the Kodalith film), and then shoot to the
size you need on sheet film, or to the appropriate size for enlarging from
35mm film. The result will be a higher resolution from your laser printer
than you would get if you created your artwork at actual size.
Best of luck to you.
file:///C|/faq.html (268 of 555) [7/19/2002 3:46:28 AM]
~NORM
- - - - - - - - - - - - - - - - - - - - - - - - - - - - NORMAN LENBURG, Photo/Imaging Instructor
Madison Area Technical College
3550 Anderson St., Madison, WI 53704 USA
trans-121
608-246-6521 (office), 608-246-6880 (fax)
...............................................................................
>Anyway my idea is this, Print out the text and symbols for whatever masks
>I'dlike to create using standard White Paper and a Laserjet printer. Then
>using a Copy stand and Kodalith Film make a mask which I can then sandwich
>with a negative and print as usual. Seems like a GREAT way to make Trading
>Cards for Little League teams and such. What speed is Kodalith available in?
>How difficult to process is it?
That is probably exactly how the masks you bought were made although I'd
think that the type was typeset and the graphics were reduced from some
significant sized original. The masks generally are used as contact masks
placed on your print during enlarging instead of masks to be used in the
enlarger. Whether a laserjet generated original is acceptable in terms of
edge quality is something you and your customers will have to decide.
Kodalith is pretty slow material, much like photographic paper. It can be
processed under a red, 1A, safelight. The chemicals tend to be significantly
more active than D-72 but if you can do prints you should not have much
trouble with Kodalith. One thing to watch for is pinholes that show up due
to dust in the black areas. These can be avoided by careful darkroom
technique or by using an opaqueing product ... dense black or red water
based dye or "paint".
andy
o o 0 0 o
o Andrew Davidhazy, at RIT's Imaging and Photo Tech Dept
\/\/\/\/\/\/
[email protected]
High Speed Photography Lab
________|
|__________________________________________________________
================================================================================
Note 30.2
-< More Wedding Photography Tips >------------------------------------------------------------------------------->I will be shooting my first wedding soon. I was wondering if someone could
>point me to a site on the web or anywhere for some pointers, FAQ's, advice?
I recommend reading as many books on wedding photography as possible.
Also go out and look at other wedding photographers work to get a feel
for types of poses to use as a starting point.
Put together a photo wish
formal poses of the bride
single, couple, and group
photographs she wants out
list with the bride and groom. For example
with the parents and family members and other
shoots. Have the bride gather some example
of bridal magazines.
Then do a couple of dry runs. Go to the wedding/reception locations and
take some photographs of the wedding couple. Practice some of the poses
and watch the backgrounds. Look for good interior locations (wooden
stairways, hallways with french doors etc.) in the event of bad weather
forces the wedding indoors. One thing I like to do is have only one ear
file:///C|/faq.html (269 of 555) [7/19/2002 3:46:28 AM]
(per subject) showing towards the camera, take a look at some wedding
photographs and you will see what I mean. Also when the lighting will
only produce a good photograph for either the bride or the groom shoot
the bride in the best light.
Notice the light levels during your dry runs and decide which film speed
is better suited for the location. Also determine what lenses are needed
or better suited per location. You might want to try out some soft
lighting effect filters while you have the chance. And no matter what
keep notes on locations and exposures and flash settings, this is very
important.
On the wedding day be sure to bring at least two cameras (one as a back
up to the other) with fresh batteries and have some spare ones in the
camera bag. During the wedding try to use both cameras for the important
shots in the event one camera is having unforseen problems.
Bring
enough film to take 720 pictures. While most weddings will only use
about 240 to 360 exposures you should always bring enough to cover the
wedding twice over. It is better to have to much film than not enough.
At the wedding don't be afraid of running out of film and don't forget to
take more than one frame per pose, try about three per pose as a starting
point. This in case some is blinking their eyes during the exposure.
If you are shooting 35mm I recommend ten rolls of VPS or NPS (160 ASA)
and ten rolls of PMC or NHG (400 ASA). You should try out a roll of each
and decide which gives you the colors you like. You might want to try
derating the film to a lower ASA for better shadow detail and a whiter
dress. Pass the samples by the couple for their input. This will also
allow you to check your camera equipment, walking the shutter and f/stop
combinations to make sure everything is working.
Be sure to use your flash whenever it is required, when in doubt take a
shot with and without the flash. Try to get a hold of a flash bracket
and flash extension cord to place the flash high oer the camera, to
prevent red eye and to throw the shadows down behind the subject instead
of on the background.
Don't forget the wedding group shot of the entire wedding party guests
and all, the best time for this shot is at the best mans toast. Have
everybody turn and face the camera and raise their glasses to the bride
and groom. You should be on a high location allowing you to shot
downwards at the party.
I recommend that you recommend to the wedding couple the use of Kodaks
wedding cameras, to be placed on the tables at the reception. This will
help cover the wedding reception events.
At the wedding remember to shoot the behind the scenes events like the
best man and groom straighten out the grooms tux or ties. Or the Mother
of the bride with the bride helping the bride with her dress or brushing
her hair. Another good shot is the bride with her father just before
they start the walk, maybe him giving her advice or kind words before
giving her away.
file:///C|/faq.html (270 of 555) [7/19/2002 3:46:28 AM]
Bottom line go beyond the average stuff you see in the wedding albums.
You are taking pictures for them to help them remember the one special
day in their lives. Don't be afraid have fun.
Good luck,
Don
From: Don Farra <[email protected]>
================================================================================
Note 30.3
-< Photo Archives of an old Photo Discussion list >-------------------------------------------------------------------------------There is, in regard to other sources, a digest of photography info at
ftp.nevada.edu in the pub/photo directory.
From: Marshall Kragen <[email protected]>
(these seem to be archives of the old "photography phorum" mailing list)
================================================================================
Note 30.4
-< 8mm and 16mm film source and brief movie primer >------------------------------------------------------------------------------->Does anyone know where to get 8mm and 16mm film cameras and film? Also
info on use of such camera would be appreciated.
I recommend you call Chambless Cine Equipment in Atlanta, 706 636 5210,
and get their catalog. The value of this catalog is that it's an
extensive description of most cameras, lenses, and accessories
available on both the used and new market for 8 and 16mm moviemaking.
You can buy directly from them--they're reliable, but their prices are
naturally high since they market to professionals. Equipment can be
picked up at camera shows --there's one in Fort Washington at the Expo
Center on June 4, for example. Local camera dealers also have this
stuff from time to time; try Fotorama, 1831 Chestnut in Phila. or
PhotoCine on 18th St. These dealers and fleamarketeers don't know much
about cine equipment so you have to do some homework to get what you
need. The upside is that prices can be quite low since these guys are
anxious to get rid of this stuff; the market for movie equip is thin.
You can get good old cameras (early 1950s; I'd avoid prewar stuff),
often with several good old lenses, for a couple hundred dollars and in
my experience these simpler cameras are better for learning how to film
than the later, overly automated ones. This includes nonreflex Bolex
cameras, Bell and Howell 70 series (the 70DR is still in production
but can be got used at a flea market for $150 or so) and the Kodak
Cine Special II and K-100, my personal favorites. >so how do you
determine exposures when doing movies?
Exposure in cine cameras is controlled through lens aperture, filming
speed (frames per second) and degree of shutter opening. Simpler
cameras have fixed shutters--they don't have control of the degree of
shutter opening, although some old 8mm cameras have it, strangely
enough. Changing the shutter opening is rarely used as a way of
controlling exposure; it's primarily a way of "fading" in and out--you
know the effect. without fades, scene changes are abrupt. One thing
file:///C|/faq.html (271 of 555) [7/19/2002 3:46:28 AM]
about movie making that surprised me is that the adjustment part of the
process--fiddling with aperture, focus, etc. is a lot simpler than
with still pictures. Focus is easy with 16 and 8mm movies since you're
using very short focal length lenses. The normal lens for 8mm is 12.5mm
and for 16mm, 25mm. These are "wideangle" lenses by 35mm standards and
have great depth of field. About all you really need to worry about is
aperture, and that's no big deal. In the late 50s, consumer 8mm and
super8 cameras often had automatic aperture control. In my experience,
this is mostly a pain in the neck. It acts very slowly, so a lot of
scenes are ruined by transitions in aperture. And, in some cameras you
can't defeat it, so when the meter gives out--and they always do
eventually--the camera is a useless piece of junk. (These later cameras
are rarely worth paying someone to fix, and nearly impossible to fix
yourself.) With a good movie camera, even with manual aperture control,
you can concentrate mostly on creating good scenes--which of course is
not so easy. Zoom lenses-- not worth the extra money in my opinion
unless you're really committed to buying yourself a new, pro outfit.
Earlier, used zooms are not as sharp as fixed focallength lenses, and
the fixed lenses can be picked up cheaper. Zooming while shooting is a
nearly useless effect, and since the lens is mostly going to be at one
focal length while shooting, why not use separate lenses?
BTW ... normal filming speed for silent movies is 16 frames per second
(since the 1950s texts say 18 frames per second) and 24 frames per
second for sound movies. The higher speed for sound is principally to
improve sound fidelity, just as faster speeds on a tape recorder sound
better. This is why old silent movies look jerky--they are projected on
sound projectors too fast. Anyhow, most cameras permit a variety of
speeds from about 8 frames per second sometimes up to 64. Filming
faster than the norm (more than 16 for silent films) produces "slow
motion" effects when projected at normal speed, and filming slower
produces the effect of watches and clocks speeding up, etc.
Chambless Cine Equipment
Route 1 Box 1595
Highway 52 West
Ellijay, GA 30450-9723
Ph: (706) 636-5210
Fx: (706) 636 5211
.... the item above was composed by [email protected] and posted on rec.photo
================================================================================
Note 30.5
-< Pinhole Cameras and Supplies Source >-------------------------------------------------------------------------------I have a 4x5 pinhole camera that I recently purchased from the Pinhole
Resource. I'm almost positive that they make several 8x10 cameras as
well. Their design would allow you to use standard 8x10 film holders
and 8x10 polaroid holders, ( if you really like to spend money! ) which
makes it rather convenient for field use. Their address is:
Pinhole Resource
Star Route 15, Box 1355
San Lorenzo, NM
88041
(505) 536-9942
file:///C|/faq.html (272 of 555) [7/19/2002 3:46:28 AM]
They also offer books, a newsletter, exposure calculators, and other
miscellaneous pinhole stuff.
From: Pietr <[email protected]>
...........................................................................
For supplies for Pinhole Photography please contact Minute Aperture Imaging.
Minute Aperture Imaging: Photographic Workshops, Supplies for lensless imaging
W. Joseph Christiansen, 7586 County H, Maplewood, WI 54226
[email protected]
414-856-6842
================================================================================
Note 30.6
-< What shutter speed to STOP motion? >-------------------------------------------------------------------------------There was a question related to determination of the shutter speed
required to make a sharp picture of a race car what would be the
exposure time required to achieve a sharp photograph? Consider this:
From: Grover Larkins, [email protected]
Florida International Univeristy
******************************************************************************
At 90 degrees between Car's direction and Camera's Optical Axis:
Race Car -Length = 5 meters,
Width = 2 meters,
Speed is 80 meters/sec.
Image Size in Camera = percent of viewfinder occupied at time of
shutter release X 36mm
Magnification is = (Image Size in Camera)/(1000 X Length of Car) -- for example
use Image size in Camera = 18mm
Max Allowable Blur is 1/40 mm for 35mm format (somewhat arbitrary but <1/30 mm)
Max Allowable Blur = (Speed in m/sec)X(Magnif)X(Shutter Time in sec)X(1000 mm/m)
Hence:
Shutter Time = (Max Allow. Blur)/((Speed in m/s)X(Magnif.)X(1000 mm/m))
******************************************************************************
If Car's Direction and Optical Axis are Co-Linear:
(Assumption that the Car is far from the Camera)
Init. Magnification = M1 -- for the example use M1 is 0.009
M1= (Width of Car in Viewfinder in mm)/((Width of Car in m) X 1000mm/m)
Dist. When Shutter Starts = d1 -- for the example use 100m
Dist When Shutter Stops = d2
delta t = t2-t1 = Shutter time
d2 = d1 +/- (delta t in sec)X(Speed of Car in m/sec)
Note:
Plus for going away, minus for approaching the camera
M2=(1+/-(Speed of Car in m/sec)X(delta t in sec)/(d1-fl of lens in meters))x(M1)
Note: Since d1 and d2 >> fl we can ignore fl in the above.
file:///C|/faq.html (273 of 555) [7/19/2002 3:46:28 AM]
Max. Allow. Blur > (M2-M1)X(Width of Car in m)X(1000mm/m)
delta t<+/-(Max Blur mm)X(d1 in m)/((Speed in m/sec)X(1000XM1)X(Car Width in m))
------------------------------------------------------------------------------Answers:
90 degrees with 50% of viewfinder => 1/11520 sec or less for shutter time
Co-Linear=>
1/520
sec or less for shutter time
Hope this Sheds some Light on the Problem,
Grover Larkins, [email protected]
Florida International Univeristy
PS -- Hummingbird Wings at 1/5 lifesize and 60 beats/sec require ~1/20,000 sec.
================================================================================
From: [email protected] (Michael Gudzinowicz)
>I'm looking for general rules of thumb for shutter speeds to stop motion ...
The other posts contain definitive answers, so I'll offer a
and its derivation.
"rule of thumb"
Simply determine the time it takes the subject to cross the frame, and divide
by 1200 to determine the shutter speed for small (5X-8X) prints. If you can't
determine the time (too fast), use the fastest speed possible and pan.
Let's assume that a 0.030 mm blur of the circle of confusion is acceptable for
an 8X enlargement (borderline). The velocity (v) of the image to moving on the
film in mm/sec is equal is the time to cross the frame divided by 36 mm.
The time to move 0.03 mm is 0.03 / v
or 0.03 * ((time to move across the frame) / 36)
or (time to move across the frame) / 1200.
For larger prints, use a smaller blur value, such as 0.015 which gives (time
across frame) / 2400 for the shutter speed. For subjects with "moving parts",
such as a person walking, consider relative motion of the "parts" (legs & arms)
which might be 2X fater than the "average" speed.
With objects moving toward or away from you, you'll have to estimate the rate
of change of magnification, or a rate to fill the frame. For a small object
relative to frame size whose rate of change of size is small, shutter speed may
not be that important. If the photo is taken during the period when an object
goes from 1/2 to frame filling size, the time to do so may be considered 1/4 of
the frame travel time above (note, the distance at the object's edge traverses
is 1/4 the frame size as it goes from 1/2 frame to full frame size. In this
case, the time to go from 1/2 to full frame would be divided by 300 rather
than 1200, though 1200 could still be used to be "safe".
The same simple approach can be used to estimate deliberate blur of a moving
object. If you want it blurred for 1/8 the distance across the print (or
negative), exposed at 1/8 the speed which it takes the object to cross the
frame. To blur the background over 1/8 of the frame, use the same speed but
pan.
file:///C|/faq.html (274 of 555) [7/19/2002 3:46:28 AM]
If you're at Indy, with cars going by at 220 mph or 322 feet per sec, you can
"guess" the frame travel time by dividing the field of view (in feet) of your
lens at the subject by 322... with a tele fast speeds and panning are
necessary, and always pre-focus.
-- Mike -- [email protected]
================================================================================
from: [email protected] (Andrew Davidhazy)
In several articles related to stopping motion the magnification factor was
invariably included in the determiantion of the necessry shutter speed to
achieve a particular degree of sharpness. I would like to add to the discussion
an observation that while including magnification as a factor may be ok it can
lead to misconceptions in terms of recording "detail" in the subject.
It does no good (sort of) to achieve a sharp image if the image is so small
that one can not see it! ... which is the inevitable result of trying to
photograph a fast moving subject with a slow shutter speed and using as a
controlling factor the magnification of the image by either moving back from a
subject or using a shorter focal length lens.
I think it may appropriate to also think about required exposure time by
simply deciding how much blur can be tolerated _at the subject_ (one then has
to be careful about specifying what part of the subject is the true subject,
like is all of it what one is interested in or a small part of it). It seems to
me that if you decide allowable shutter speed in terms of the subject size
magnification becomes irrelevant and what you will want to use in fact is the
largest possible magnification to keep emulsion "noise" down.
Basically what I am thinking is that it makes no sense to photograph with a
short focal length lens if later on one will enlarge the image to the same size
it would have been with a longer one.
Don't get me wrong, either approach will work but in terms of resolvable detail
it turns out it does not matter at all what the magnification was ... blur is
simply a factor of exposure time (sure motion angle also enters into it but
that is a longer story) and subject velocity.
.... what do you think?
andy, [email protected]
================================================================================
Note 30.7
-< Filter to make color scene look as B&W sees it! >------------------------------------------------------------------------------->There is a filter used to show the contrast or lack of same in a scene and to
>give the viewer a look in almost black and white tones to see if the potential
>photo would give a reasonable bxw pix. What is the number of this filter?
FYI, the viewing filter is the Wratten # 90 Monochromatic Viewing Filter.
The Wratten catalog (1945) description follows:
"This filter, No. 90, of a pure yellow color, transmits a narrow region of the
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spectrum. Although it is possible to distinquish between a red and a green
viewed through this filter, the difference between colors is so dulled that
they no longer materially affect judgement as to their relative luminosity. It
is of course, impossible to construct a filter which will remove all appearance
of color from a subject, and at the same time strictly retain relative
luminosities. The filter we have produced is, we believe, the best compromise
which can be obtained; it will enable all workers who are in the habit of using
orthochromatic methods for the reproduction of colored objects to anticipate
the effect upon the photographic material before exposure. This knowledge will
also show when it may be necessary, as it sometimes is in special cases, to
modify a strictly orthochromatic reproduction by allowing play to the effects
of color contrast by the use of suitable filters."
In other words, it suggests where tones are likely to merge, which is useful
information since colors may appear quite different, though the tone reproduced
on film might be the same. Gels may be acquired at dealers and mounted in the
aspect ratio of the format between plastic sheets to prevent damage.
The total transmission is 12% (8X) which gives it a very deep yellow/brown/
sepia look. An insignificant amount of blue and green light to 550 nm are
transmitted (a "peak" of 1% at 340 nm); at 575 transmission rises to 35%,
drops to < 1% at 650 cutting red, and rises in the near IR.
From: [email protected] (Michael Gudzinowicz)
===============================================================================
Note 30.8
-< Polarizers for Infrared Photography - Q&A >------------------------------------------------------------------------------->A while ago, I read in an older German book [printed in 1979] that a normal
>polarizing filter has no effect on IR-film (black&white), since true
>IR-waves are not affected by the common polarizers; apparently it looses
>its polaring-effect in the longer wavelengths. The book suggested to use
>IR-polarizing-filters....
What is actually the case is that the material used in "regular", light,
polarizers transmits IR so obviously these will not polarize IR.
>I spoke to a specialist from B+W filters; filters like these are no longer
>in production, the only current type that polarizes IR works only between
>1000 and 1200nm, and are 100% black to the naked eye. Estimate price for
>this filter in the size 100x100mm is above 700 US$....;-( Does anyone know
more about this kind of polarizing filters? Brand, type, sizes, and price?
Polaroid does in fact sell Polarizing material that is effective in the near
IR. Still not cheap but available. You can order direct from Polaroid by
calling 1-800-225-2770 and they also will send out product spec sheets on
request. I was able to find out that material which works between .8 and 2.2
microns is called HR4 and the product number for a 2x2 inch piece is 605211 and
cost is $ 116 each, for a 3" square the number is 605212 and price is $182 ...
they also have larger sizes and may have near-ir polarizing filters as well.
^^^
andy, [email protected]
............................................................................
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Here is a summary of the information about IR-polarizers that I found
up til now:
Besides B+W, the Goettinger Farbfilter GmbH also produces IR-polarizers, but,
like B+W, only above 800nm (same type I guess as the polarizer Andrew
Davidhazy mentioned). Price?, oh well....10 to 20 DM....but not per filter,
_per cm2!_ ....for 10x10cm that would be ehh....up to 1500 US$....
But I also spoke to Ian Gobey from the Polaroid Filters (European) headquarter
in the UK. At first he told me that they had only one IR-polarizing filter,
for use between 800 and 2000nm. But after mentioning the 'HN 7'-type, he could
remember that there was a type not listed in the regular productcharts. He
contacted Polaroid USA, and confirmed that this HN-7 type (working between 700
and 900nm) was still available, but on special request order only. It was
definately not on stock, not in the US nor in Europe. Delivery could take 4 to
6 weeks. Estimate price was 70US$ for a sheet of 12"x12", 0.015 thick
(propably mm, but I am not sure about this).
Found not only the right filter, but for a very reasonable price
also!....:-))
The only thing that puzzles me right now, is, whether typical 'broadband'
IR-polarizers also exist. Since the Ektachrome, used with a orange filter, is
sensitive to the range between 500 and 900nm, the Polaroid HN 7 filter would
have no effect on the visible range. Perfect solution would be a IR-polarizer
that has a continuous working range between 500 and 900nm....
Any ideas, beside the obvious stacking of a normal *and* a IR-polarizer?
BTW, I also discovered an interesting feature of normal polarizers. When
cross-polarizing two normal (linear?) polaroid filters, the dark setting has
no effect on IR-waves, thereby making it a perfect black IR filter! (my German
book says it equals a 87 filter!).
I am curious what kind of effect this will
have on the Ektachrome, since no visible color filtering takes place....the
colors don't change as with the recommended orangefilter....and the filtering
is continuous, from 0% to 100% black, so in-between-effects are also
possible....curious! I smells lots of experiments....;-))
From: MARKERINK <[email protected]>
Subject: IR-polarizer!
==============================================================================
Note: 30.9
-< What makes a macro photograph? >----------------------------------------------------------------------------->>Subject: Is close focus = macro? If not, could some one tell me what is the
>>difference.
>Close focusing doesn't necessary mean macro. When using the same lens say
>50mm. you will get higher magnification as you get closer to the subject.
>You can get closer by several method(the easiest is the closeup attachments).
>As you use stronger attachments, you get closer and the image gets larger.
>The other and better way to get higher magnification is to use a telephoto
>lens say 200-300mm. By this way, you get much higher magnification without
>the need to get closer to the subject. This is spicially true for
>photographing living beings such as butterflies that get scared and fly away
>if you get very close to them.
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Macro or photomacrography generally simply refers to the magnifcation of the
image of the subject at the film regardless of what focal length or film format
you are using. The "macro" range is usually described as images whose
magnification is something between 1:10 life size and 20 times life size but the
"limits" if you want to call them that are quite flexible. Another way to think
about this range is that as long as you are using a "standard" lens you are not
in the "macro" range (unless the lens gets you to 1:1 or life size or so) and
if you have to use a microscope in front of your camera then you are in the
photomicrograph range and again not "macro". Anything in between is macro!
A second point referring to the above post is that while it is true that for a
given object distance a longer focal length lens will produce a bigger image
size most telephoto lenses do not allow you to focus as close as a shorter lens
does so you may not get the close-up magnification that you get with a shorter
lens. For nature photography (and in fact most other applications as well) it
is good advice to use the nongets focal length possible to achieve a given
magnification because this means a longer working distance and less likelihood
of the camera or lens interfering with the photography.
andy, [email protected]
.............................................................................
>>For nature photography (and in fact most other applications as well) it
>>is good advice to use the longest focal length possible to achieve a given
>>magnification because this means a longer working distance and less chance
>>of the camera or lens interfering with the photography.
>i am curious about this last advice, as I don't have much experience with
>macro work. I would tend to think that at close-up focusing, depth of
>field is so shallow that one might want to use the shortest focal length
>that gives a comfortable working distance from the subject, (which will
>vary with subject, eg flower/butterfly/grizzly bear nostril), or a focal
>length that gives the desired perspective.
In macro situations the one-sided depth of field is given by Ne c / M^2, where
Ne is the effective f-stop (corrected for bellows factor), c is the diameter of
the largest acceptable circle of confusion, and M is the magnification. Note
that f, the focal length does not appear. Thus the DOF does not depend on
focal length. (In case you are wondering if it is lurking in Ne, no, as Ne = N
(1+M), where N is the "marked" f-stop.)
(Note the qualifier above. DOF does depend on focal length when the subject
distance gets close to the hyperfocal distance. See the Lens Tutorial - (also
available for [email protected] with Subj: faq-lenses$txt)
From: [email protected] (David Jacobson)
...............................................................................
There's a crucial issue being left out of this discussion. A lens by one
of the reputable mfrs sold as a micro or macro lens will not only focus
close, but IS DESIGNED OPTICALLY TO DO A GOOD JOB AT CLOSE DISTANCES.
Optimum lens design for shooting in the 1:2 or 1:1 range, not to mention
closer, is quite different from optimum lens design for "normal" (10 ft to
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infinity) design. Ironically, some of the "micro" lenses---I'm familiar
with the Nikon line, as it happens, do very well at infinity; but the same
certainly can't be said of (say) their 50mm f 1.4 when bellowed out or
extension ringed out to do an ultracloseup. Volumes have been written
about this, but the routine amateur needs to know that for close up work
(a) just racking out the "normal" lens further WON'T get a very sharp
picture, and (b) the so-called macro setting on a lot of the newer Zoom
lenses, while a convenience, again, won't produce work of the quality of a
purpose-designed macro lens.
[email protected]
==========================================================================
Note 30.10
-< Making B&W slides from B&W negatives >-------------------------------------------------------------------------How to make b/w slides from negatives.
Some time ago, I enquired about methods to obtain black and white slides from
black and white negatives. I received many answers, and in particular I had
long email discussions with Ron Speirs. He taugth me a very simple and
effective procedure, that I followed with very rewarding results. In this post
I will present that procedure, together with some additional suggestions.
Let me remark that black and white slides can be truly beautiful. Their tonal
range greatly exceeds that of b/w prints, and often exceeds that of color
slides. You can see the most brilliant highlights side to side to detail in the
deepest shadows, without sacrificing the overall contrast.
Also, making b/w slides from negatives takes far less time than making final
prints. I once used to spend hours printing, and there were still many, many
negatives that I would have liked to see, but had no time to print. Now I can
quickly make slides from all the interesting negatives, and I can print only
the ones that I feel deserve it. I can do my snapshooting in b/w now!
The method.
The method is rather simple. With a slide duplicator, shoot duplicates of the
negatives on Kodak 5302 Fine Grain Positive Release Film, then develop in Kodak
D-11.
The film.
Kodak 5302 film is sold in 100 ft rolls, so that you need a bulk loader to load
it in film cassettes. It is very inexpensive: a 100 ft roll is about $12. Other
films that can be developed to a moderately high contrast would do as well: for
example, Technical Pan. I stick to 5302 because it is so inexpensive, it
tolerates process variations fairly well, and because I don't want to begin
again testing exposure and development times for a different film.
The duplicator.
I use a Rokunar 1:1 non-zoom slide duplicator. It is a fixed f/8 duplicator,
and the quality is good enough for my taste. This means that the weakest link
of the chain is the quality of my projecting lens, and not the quality of the
slide duplicator. The duplicator requires a T-mount, that is rather
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inexpensive. Mail order, one can get the duplicator and the T-mount for $65 +
shipping.
The type of the duplicator is important. The duplicators are normally designed
for slides, not for negative strips. The above 1:1 duplicator can be used with
negative strips; but I don't know whether the same applies to other brands or
to zoom duplicators.
With the above duplicator, all you need to do is to get one of those glassless
slide mounts with hinged cover, such that the hinge runs parallel to the long
side of the slide. Then, file the mount so that you can slip in it a whole
negative strip without the mount scratching it. The mount should still be able
to grip the film strip so that it won't move. Once this is done, it is very
simple to position the slide mount on the negative strip and copy one frame at
a time.
Exposing the film.
Kodak 5302 is not very light-sensitive: depending on the blue content of the
light, it is between 1.2 ASA and 0.3 ASA. In fact, the film is blue sensitive,
and can be handled under a red safelight (see the instructions packaged with
the film).
I have found that the best way of exposing it consists in shining the light
from a slide projector on the white piece of diffusing plastic of the
duplicator. This is the most intense light source that I have available in my
darkroom. I keep the duplicator about 15 cm from the projector lens. One must
be careful that the light from the projector illuminates uniformly the piece of
white diffusing plastic.
I set the ASA dial of my camera to 50 ASA, and when I read an exposure time
between 1/15 and 1/8, I set the shutter speed to 2 seconds. This is a starting
point (but works fairly well). As usual, you can change this to obtain
particular effects: longer time for a darker slide, shorter for a lighter
slide. The film does not seem to suffer much from reciprocity failure for these
times. I did not find mirror lock-up to have much effect on the sharpness of
the duplicate.
Processing the film.
I develop Kodak 5302 in working-strength D-11, for about 6 minutes at 20 C,
with 2 inversions every 30 seconds. Then, I follow the usual processing steps:
stop bath, fix (I use two baths of Ilford rapid fixer for two minutes each),
rinse, hypo clear, final wash. By varying the development time, it is possible
to control somewhat the slide contrast.
I found that Dektol and HC-110 do not provide enough contrast for my negatives:
the slides have a grayish look, and the maximum density is not high enough.
Dektol can be a useful developer for negatives that have a higher contrast than
mines, though.
Luca de Alfaro ([email protected]) (opinions stated here belong to me, and
do not necessarily reflect those of my employer).
==========================================================================
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Note 30.11 -< Photo Attractions in Boston, Chicago, Las Vegas & Mobile >-------------------------------------------------------------------------BOSTON .....................................................................
>
>
>
>
Later this month I will be going to Boston and Northern New England for the
first time. I'm from Arizona and this part of the country will be new and
different for me. I could use some suggestions on what to see and photograph
to get a feeling for the culture and environment of the area.
I live outside of Boston and have never been to Arizona, and have only seen
photos. Depending on what you are interested in, NE has a very wide variety of
scenery. Boston itself is very attractive, with buildings dating back over 200
years, so the architecture would probably be very different from what you are
used to. Cape Cod National Seashore is one of my favorite places. There are
sand dunes, but probably very different from what you are used to seeing in the
SouthWest. For Historical Interest, Plimouth Plantations and Old Sturbridge
Village are interesting for their perspective on life in Colonial America, and
the architecture and town layout. North of Boston are the towns of Gloucester,
Rockport, Magnolia, and Manchester. These offer very different scenery, as the
coast there is very rocky (Rockport is very appropriately named) which is quite
different from the Cape Cod coast line 2 hours away. These towns are on Cape
Ann ("The Other Cape"). Rockport has a red fishing shack on a pier jutting out
into the harbor, which has the reputation of being one of the most photographed
and painted buildings, at least in New England. It is usually referred to as
"Motif No 1".
Further north into Maine the coastline is also very rocky, with long rocky
inlets from the ocean. The mountains in New Hampshire are much older than the
Rockies, so they are considerably more worn down, and not as striking, but
beautiful in their own right.
There are towns throughout the area, which may not necessarily have anything
particularly distinctive, aside from having town centers which have not changed
much in 200 years. For some of them, perhaps spring, when all the flowers are
in bloom, and fall, when the leaves are turning, are the prettiest times to see
them, but they might be worth a visit depending on your time frame.
From: Bill Leigh, [email protected]
CHICAGO ........................................................................
>
>
>
>
I will be travelling to Chicago. I will only be there for three days but I
hope to do some sight-seeing and hopefully get some shooting in. I will be
quite limited to the downtown area and would appreciate it if anyone has any
suggestions of good places to visit (and any areas I should avoid)
Chicago is a nice place to visit, and you know the rest. It is full of
interesting things to photograph. I particularly like Michigan Ave. w/ the
colorful people and street musicians. Perhaps for a donation, they will let you
photogaph them. The tall buildings are awesome, as is the view from the John
Hancock and Sears Towers which you can get about a fifty mile view on a clear
day. Night is also spectatular. I like photographing the skyline and it's
reflection in Lake Michigan from the Adler Planetarium. It 's a small peninsula
that juts out in the lake. It makes a great view just after sunset. Be sure to
pick up a map of downtown. The Chicago River has many drawbridges with various
vessels afloat. Also, Chicago is known for it's modern architecture. As a
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country boy, I am facinated by the lights, glamour and excitment of Michigan
Ave. On my first visit, I sunburned the roof of my mouth. Check out the great
museums, The Art Institute, Museum of Science and Industry, and the Field
Museum of Natural History. An awful lot for three days. Have Fun.
Always the Art Institute and the Museum of Contemporary Photo south on Michigan
From: Kim Mosley <[email protected]>
MOBILE (Alabama) ..............................................................
In addition to the USS Alabama, in downtown Mobile you have historic Fort Conde
which is a partial restoration of the orginal city hundreds of years ago. There
is also Fort Gaines located on Dauphin Island about 25 miles south of the city.
Fort Morgan is located opposite Gulf Shores in the next county. Both Forts
Morgan and Gaines protected the mouth of the Bay from invasion during the Civil
War. Very little has been done to Fort Morgan. It is pretty much in ruins as I
recall, but picturesque. Fort Gaines has been restored and is a thriving
tourist attraction. There is a Ferry that links both Dauphin Island and Fort
Morgan. The trip last about 30 minutes. The alternative is about a 1 1/2 hour
drive by car. Since I am here, will be glad to answer any additional questions
you or anyone else may have.
From: [email protected] ("Robert A Vogtner")
more:
The boat's there, but if I may jump in with an alternative suggestion: don't
miss the gardens if you're in the area -- Bellingrath (spelling?) Gradens are
world class. They are grand southern gardens -- plantation style opulence. If
you have to choose, forget the boat.
From: Joe Angert, St. Louis Community College, <[email protected]>
LAS VEGAS......................................................................
> Will be heading to Las Vegas in August. Can anyone tell me some good sites to
> photograph (Outside of Vegas)? Will have a rental car so that will not be a
> problem. Let say about a fifty to hundred mile range of Las Vegas.
You may want to consider visiting Hoover Dam and Lake Mead south of Las Vegas.
Raft trips down the Colorado River below the dam are available (much more
sedate than the ones through the Grand Canyon!).
Local Las Vegas attractions (*besides* casinos) include Red Rock Canyon
Conservation Area about 45 minutes west of town along the Spring Mountains, Mt.
Charleston (also in the Spring Mt. range) (ele. ~12,000 feet) northwest of town
about an hour and Valley of Fire State Park northeast of Las Vegas about an
hour by freeway. Two photo-l members who have visited Las Vegas have really
enjoyed their trip out to this park, noted for its firey red rock formations.
From: [email protected] (Erik Jonker)
Yes try "Valley of Fire" state park N.E. of Las Veges, great for late afternoon
shots with sun low in the sky.
From: [email protected]
Hoover Dam would be a start... :-)
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Near Boulder City. I'd take a helo ride
from SunDance Helicopters - get the LEFT side in the passenger area and shoot
through the sliding vent.
Red Rock - you will need to find out sundown time and get there about an hour
before - the place really mellows as the sun drops in the sky. Good cacti
against a red background!
From: [email protected] (Roy Roper)
Be prepared for the heat (100-120) when you come out in august.. :)
after
living here almost 6 yrs im still not used to it. PS: if you're tight on time
(can't go to red rock and valley of fire) i would say skip red rock and head
out to valley of fire its much nicer IMHO. sunsets/rises at valley of fire are
beautiful, at red rock you have to wait for the sunsets.
From: Casey Lewis, [email protected], University of Nevada, Las Vegas
The Mormon Temple in Las Vegas is really cool at night...
From: Brett Pfingston ([email protected])
==========================================================================
Note 30.12
-< Favorite Textbooks of PhotoForum readers >-------------------------------------------------------------------------The Focal Encyclopedia of Photography by Stroebel & Zakia - Focal Press
should be a required reference and considered for the upcoming gift-giving
season. :)
From: [email protected] (Eugene Kowaluk)
Photography From Theory to Practice from Star Publishing is a good basic text.
From: "Leary, Mike" <[email protected]>
Photography and the Art of Seeing - Freeman Patterson
Photography of Natural Things - Freeman Patterson
Both are excellent books. The first is my favorite. FP also now has a book out
which is a "workshop in a book" book. Have not seen it yet but it's on order.
From: [email protected]
One of the books that I rely upon constantly is:
_Photographic Facts and Formulas_ by E.J. Wall and F.I. Jordan. (a more recent
version, was edited by J.S.Carroll and appeared from Focal Press in 1975.)
This is more of a reference book, I guess, but it is so full of information I
just don't understand why anyone would try to get by without it.
From: Larry Bullis <[email protected]>
I have found the following to be of interest:
1.
The Burden of Representation - John Tagg 1988
2.
13 Essays on Photography- Canadian museum of Contempory Photography 1990.
3.
Classic Essays on Photography - ed. Allen Trachtenberg 1990.
4.
Photogenic Papers - ed. John Richardson (Continuum - The Australian
Journal of Media and Culture, Vol 6, No 2 1993)
5.
The Critical Image: Essays on Contempory Photography - ed. Carol
Squires, Bay Press Seattle 1990.
6.
Disrupted Borders: An Intervention in Definitions of Boundaries - ed.
Sunil Gupta,Rivers Oram Press / London1993
From: [email protected] (Brett McLennan)
The book " Photographers On Photography" edited
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by Nathan Lyons is an
excellent collection of essays by photographers. Unfortunately it is out of
print also. I have found "Seeing with the Mind's Eye" by Samuels & Samuels to
be a good book to get students thinking creatively.
From: Russell J Rosener <[email protected]>
I have twice used as a text Mark Jacobs and Ken Kokrda's *Photography in
Focus*. In many ways it is an ordinary textbook, but it does contain some
rather well-presented chapters on photograms, pinhole cameras, "visual aspects
of photography," special processes and techniques, and the history of
photography. It was the chapter on the history of photography that initially
attracted me to the book: although it's short, it does give the students some
readymade "notes" which I am able to amplify with lectures and slides.
I also recommend that students have a look at Terry Barrett's *Criticizing
Photographs: An Introduction to Understanding Images*. Barrett presents a good
*introduction* to art criticism and to aesthetic theory, and does an especially
nice job regarding describing, interpreting, and evaluating photographs. These
last three sections are very helpful when we begin critiques.
From: "David L. Rayfield" <[email protected]>
There are a couple of books which are my favorites, (though I have a vested
interest-I have workbooks available for each.) One is Henry Horenstein's
classic, Black and White Photography and the other is David Curl's
Photocommunication. If you are a teacher, please email me if you would like
sample copies of either (and/or the workbooks which accompany them.)
From: Kim Mosley <[email protected]>
"vintage and classics"
Handbook of Photography by Henney and Dudley - Whitlesey House
Ilford Manual of Photography - Ilford
Applied Photography by Arnold, Rolls and Stuart - Focal Press
The Photographic Process by Mack and Martin - McGraw Hill
Principles of Photographic Reproduction by Miller - MacMillan
Fundamentals of Photography by Neblette - D. Van Nostrand
Fundamentals of Photography by Boucher - Morgan and Morgan
View Camera Technique by Stroebel - Focal Press
In-Water Photography by Mertens - Wiley Interscience
and books by Langford (Focal Press) and Blaker (Freeman)
I also can't resist picking up any book by Andreas Feininger
but they all tend to look alike after a while! :-)
From: [email protected] (Andrew Davidhazy)
Amateur Photographer's Handbook by Aaron Sussman. I have noticed how quickly
I whip out my cash whenever I find a used copy this book. I always know some
student who needs a book that has a lot to say about the basics. I like to
have a few on hand to give away.
From: Larry Bullis <[email protected]>
==========================================================================
Note 30.13
-< The Argyrotype Process >-------------------------------------------------------------------------ARGYROTYPE
Mike Ware
(version of 12 August 1994)
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A new 'user-friendly' iron-based silver printing process, related to the
Kallitype, Argentotype, Sepia, Brownprint and Van Dyke processes of the
19th Century, but offering some advantages over them in the economy of
materials and effort, and in the quality and permanence of the image.
Sensitizer Chemicals needed:
Sulphamic acid 7 g (spelt 'sulfamic' in the USA)
Silver(I) Oxide 7 g
Ammonium Iron(III) Citrate (green crystals) 22 g
Tween 20 (wetting agent) about 0.2 cc
Distilled water to make 100 cc
Making up Sensitizer (under tungsten light)
1) Heat about 70 cc of distilled water to 50-60 C, and dissolve 7 g of
Sulphamic Acid in it.
2) Add 7 g of powdered Silver(I) Oxide to the hot solution 1) in small
amounts with vigorous stirring until all is dissolved.
3) Add 22 g of Ammonium Iron(III) Citrate (the green variety) to the warm
solution in portions, with stirring, until it is all dissolved. Allow to
cool.
4) Add 0.2 cc of Tween 20 and mix well.
N.B.The appropriate quantity of this wetting agent is variable and will
depend on the paper used.
5) Add distilled water (at room temperature) to make a final volume of 100
cc and filter the solution to remove any small amount of solid remaining.
(The solution should be a clear deep olive-green colour.)
6) Store in a brown bottle in the dark at room temperature.
(The solution should keep for a year, at least. If it throws down a small
amount of black precipitate, it should be re-filtered.)
7) To make a more contrasty sensitizer, dissolve an extra 1 g of sulphamic
acid in 100 cc of sensitizer.
CAUTION The solution is toxic and will stain skin and fabrics: wash away
spillages with plenty of cold water.
Papers
The purity of the paper is critical: of the UK papers tested so far,
Whatman Watercolour, Saunders Somerset and Atlantis Silversafe Photostore
are recommended, but the best is Ruscombe Mill's handmade Buxton paper. The
wetting agent, Tween 20, is included in the sensitizer formulation to
assist uptake of the sensitizer by the cellulose fibres, which minimises
"bleeding" of the colloidal metal image during processing, but it may cause
uneven penetration of some papers that contain a mixture of fibres.
Discovering the best paper is a matter for personal experiment.
Coating
A 10"x8" coat requires about 1.6 cc, depending on the paper, if a glass rod
spreader is used. Brush coating will consume more.
Allow a few minutes for the sensitizer to soak in, until the paper surface
appears non-reflective, then dry for about 10 minutes in a stream of warm
(40 C) air. Alternatively, simply allow to dry at room temperature and
humidity for about an hour. The sensitized paper should be used within a
few hours, unless a desiccated box is used for longer term storage: 'shelf
life' in a dry environment is at least a week.
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Printing
As with platinum-palladium printing, a negative with a long density range
(0.2 to 2, or so) is desirable, obtained by "overdeveloping" by 70%-80%.
Softer negatives may be accommodated by using the more contrasty sensitizer
recipe. [Indeed, by mixing the two formulations, the contrast of the
sensitizer could be 'fine-tuned'.]
Printing is by contact, using a UVA source or the sun. Exposure is similar
to other iron-based processes, e.g. platinum/palladium.
If the relative humidity of the paper is 'normal' (ambient RH between 40
and 80%), a detailed print-out image will be obtained, orange-brown on a
yellow background, which gives a good indication of correct exposure,
making test strips unnecessary. A little development (half to one stop) can
subsequently be expected to occur in the high values during wet processing,
and there will be considerable 'dry-down' of the tonality: both factors
should be taken into account in judging exposure; the colour will also
darken to a rich brown in the fixer bath. It is better to overexpose than
underexpose, because a dense image can be 'reduced'.
Colour
The colour of the print-out image may be shifted to a more neutral tone if
the sensitized paper is humidified before exposure by leaving it above
water (100% RH) for 30 minutes at room temperature. This is a very
economical method of colour control!
CAUTION: Humidified sensitized paper can damage negatives during contact
printing unless a protective layer of very thin polyester film is
interposed between the two.
Wet Processing
This is extremely simple and non-critical, requiring only one inexpensive
solution, 2% Sodium Thiosulphate: dissolve about 20 g of the crystals in 1
litre of water. This bath has a capacity of about ten 10"x8" prints and
should be replaced when necessary.
1) Develop and clear in running water at room temperature for 5 mins.
2) Immerse in the 2% Sodium Thiosulphate clearing bath for about 3 mins.
3) Wash the print in water for 20 mins and air dry at room temperature.
NOTES:1)
The yellow unexposed sensitizer should disappear completely within
this time. If there is any "bleeding" of colloidal silver metal, indicated
by a red-brown stain running off the image and loss of image density, then
this problem results from the paper fibres failing to trap the tiny silver
particles; it is especially likely if insufficient Tween is used. The
effects of "bleeding" may be minimised by processing the print face down,
to avoid staining adjacent areas. If a particularly long tonal range is
desired with very delicate high value gradations, the exposed print should
be left in a humid atmosphere (100% RH) for ten minutes before wet
processing; several steps of highlight detail will build up.
2)
The image should intensify in the fixer, improving the shadow
gradation, and the colour will rapidly transform from red to brown. (As the
bath 'ages' its action in this respect increases). Overlong treatment in
this bath and exposure to air will result in loss of image density
especially in the highlights; it may be used to 'reduce' an overexposed
print, or a standard, non-acid fixer may be used. If, on the other hand,
very delicate highlight detail is desired, a little ammonia may be added to
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the clearing bath to make it distinctly alkaline (pH 9 to 10); this
inhibits the dissolution of silver, but may raise the level of residual
iron in the image.
3)
The image 'dries down' significantly - at least one Zone. Heat
drying on a ferrotype plate or by ironing, may shift the colour to a more
neutral blackish brown.
Permanence
Like any colloidal silver image, an Argyrotype is inevitably rather
susceptible to attack, especially by acids and sulphur-containing
substances. However the residual iron and silver in the unexposed areas
should be very low and image stability and lightfastness are good.
If improved permanence is desired, then try selenium toning (Kodak selenium
toner, diluted 50 to 100 times for a minute or so). Toning with gold,
platinum or palladium should also be possible, and the image should also
respond readily to sulphide toners, but I have not yet tested all these
options.
Disclaimer
This information may be copied and circulated freely (preferably with
acknowledgement!), but the author cannot accept liability for any injury,
damage or loss resulting from its use.
Reference
'The Argyrotype Process' by Mike Ware, British Journal of Photography,
No.6824, 13 June 1991, pp. 17-19.
Note 31.1
-< Porter's Camera Store and Catalogue info >-------------------------------------------------------------------------------I order from Porter's frequently and have always been satisfied
with their service. They sell cameras, lenses, developing & printing
supplies, tripods, cases, etc. and all kinds of interesting gadgets.
Porter's Camera Store, Inc., Box 628, Cedar Falls, Iowa 50613-0628
Warehouse Outlet Store: 323 Viking Road, Cedar Falls, Iowa
Porters advertises a free catalog (it's over 100 pages) that you can
receive by calling 1-800-553-2001.
From: Joyce Sandy, [email protected], College of Education
Arkansas State University, P.O. Box 940, St. University, AR 72467
PHONE: 501-972-3057 FAX: 501-972-3828
================================================================================
Note 31.2
-< Light/Dark and Sound Sync w/delay & intervalometer >-------------------------------------------------------------------------------Schematic of Light/Dark and Sound activated synchronizer
with adjustable delay (analog) and Intervalometer setting
(c) A.Davidhazy * non-commercial use and distribution ok!
._______._.__________.____.___._________._______.____________.
|
| |
|
|
|
|
|
|
|
| |
%
|
|
|
|
|
|
|
| +-> % 1M
|
|
|
|
|
|
|
|
|
_|____|___|__
# 22K
# 10K or so |
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|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
--
22K #
+----|1 4 14 10 |
|
|
|
|
|
|
12 |---. |
|
|
|
+----|2
|
| |
|
V
100K |
|
|
13 |---'-----+----'
+ 12 volts
.--+---- | ---|6
|
| |
(pack of 8 1.5 volt batteries)
| |
|
|
8 |--+---' |
.>% =.001 |
|
556
| = .01 |
| % |
|
|
5 |--+----- | -----+
|
|
|
|
|
|
| 1N4004
|----|
|
|
9 |-------------+-------+--|>-+--> to relay
|
|
|
|
|
|
| |
|
|
|
|
|+
|_3____7___11_|
|
# # 1K |
|
|10uf =
|
|
|
10uf =
| |
|
^ 1n4004
|
|
| .01 =
|
= .01
|
0 0 led|
|
|
*
|
|
|
|
|
| |
|
|
|
/
|------+----*----+---------------+--+----------+--> to relay
|
*
|
|
2 1
|
|
| repeat switch
*
| timers
|
|
|
/ power switch
|indicators |
|
V
*
|
V
|
A
|
|
to A
|
GND (- on 12v battery)
|
|
.____________ | ____.
|
.______|_________.
|
|
| -----------------|*
*
.* |
|
|
FPT100 or equiv
|
|
________/
|
|
\| phototransistor
|__________________|*-'
*
*------'
/|
or
|______|______|__|
|
microphone input
DPDT SWITCH
10K +-###--+
|
|___________________|
DARK <-----> LIGHT/SOUND
Andrew Davidhazy, at RIT's Imaging and Photo Tech Dept, [email protected]
================================================================================
Note 31.3
-< Kodak B&W Sheet Film notch codes >-------------------------------------------------------------------------------Code Notches and ISO speeds for KODAK Black and White sheet films.
All on Estar Thick Base unless otherwise specified.
__________
Commercial 6127, 4127
(not on Esatr Thick base)
__
\/
Daylight
ISO
Tungsten
ISO
20/14
8/10
100/21
80/20
100/21
50/18
100/22
100/22
_____
|__|
______
_ ___ _ ____
\/ \/
\/ \/
Contrast Process Pan 4155
______
Contrast Process Ortho 4154
_ ___
_____
\/ \/
|__|
____________
Ektapan 4162
_
___
\/ |___|
_______________
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___
Fine Grain Positive 7302
(not on Estar Thick base)
|___|
40/17
10/11
10/15
6/9
_ ___ _____
\/ \/
\/
40/17
36/16
_ _ ___
__
\/ \/ \/
|___|
125/22
125/22
320/26
320/26
_ _____
\/ \/
200/24
200/24
_ ____
_
__
\/ \/
\__/ \__/
320/26
200/24
1250/32
1250/32
400/27
400/27
100/21
100/21
400/27
400/27
25/15
12/12
Kodalith Ortho 2556, Type 3
(Estar base)
not notched
_______
Kodalith Pan 2568
(Estar base)
____
Plus-X Pan Professional 4147
_________
_ _ _____
\/ \/ \/
Tri-X Pan Professional 4164
____________
Super-XX Pan 4142
__
Tri-X Ortho 4163
___
_ _ ___
___
\/ \/ \/
|___|
Royal-X Pan 4166
____________
___
Royal Pan 4141
___
\/
_____
T-Max 100 Professional 5052
(not on Estar Thick base)
\/
________
_____
\/
\/
_______
. _
____
\/ \/ |___|
T-Max 400 Professional 5053
(not on Estar Thick base)
__
Professional Copy 4125
____
\/
__
\/
_
_
\/
_
____
\/
_
\/
___
\__/
____
\/
____
__
____
\/ \/ \__/
__
Separation Negative 4131, Type 1
(not on Estar Thick base)
__
__________
Pan Masking Film 4570
(not on Estar Thick base)
Pan Matrix 4149
_
\/ \__/ \__/
__
Matrix Film 4150
_
______
\/
_
______
\/ \__/ \__/
_______
__
_____
Separation Negative 4133, Type 2
\__/ \__/
(not on Estar Thick base)
____ ___ ___ ___
___
High Speed Infrared 4143
\/
\/
\/
|___|
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-when notches are at the right side of the top edge the emulsion is facing youandy, [email protected]
================================================================================
Note 31.4
-< US Photography Related Magazines List >-------------------------------------------------------------------------------US Photographic Magazines & Newsletters - list compiled by Lance W. Bledsoe
[email protected], 30 Jun 1995
(...plus some more as seen on the "net")
AMERICAN PHOTO
1633 Broadway
New York, New York 10029
A bi-monthly, glossy magazine devoted to the art of photography.
APERTURE MAGAZINE
20 East 23rd Street
New York, New York 10010
A quarterly magazine dedicated to fine art photography.
ART DIRECTION MAGAZINE
10 East 39th Street
New York, New York 10016
A monthly magazine offering art director's views on photography and
advertising.
ASMP BULLETIN
419 Park Avenue South
New York, New York 10016
A monthly newsletter issued to members which reports on trends and
business pertinent to the field of magazine photography.
COMMERCIAL IMAGE
PTN Publishing Co.
445 Broad Hollow Road
Melville, NY 11747
(516)845-2700
Monthly - geared to commercial/professional photographers
GREETINGS MAGAZINE
309 Fifth Avenue,
New York, New York 10016
A paper products trade publication.
THE GUILFOYLE REPORT
Published by AG Editions
New York City.
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A quarterly tipsheet for nature and stock photographers.
THE IMAGE BANK NEWSMAGAZINE
Published by TIB
Profiles Image Bank photographers and their work. Also covered are such
topics as news, electronic imaging, and fine art photography.
LOUPE
49 East 21st Street
New York, New York 10010
A quarterly magazine, produced by PHOTO/DESIGN MAGAZINE, which showcases
the work of stock photographers.
(Loupe is a supplement to Photo District News who folded the
Photo Design book and incorporated that feature in the Newspaper.)
-- Gary Gladstone, [email protected]
NEWS PHOTOGRAPHER
3200 Croasdaile Drive
Suite 306,
Durham, North Carolina 27705
A monthly magazine produced by the National Press Photographer's
Association for still and television news.
OUTDOOR PHOTOGRAPHER
Suite 800
16000 Ventura Boulevard
Encino, California 91436
A monthly magazine devoted to the techniques and needs of outdoor
photographers.
PETERSEN'S PHOTOGRAPHIC
8490 Sunset Boulevard
Los Angeles, California 90069
A monthly magazine covering all aspects of photography and geared toward
all levels of expertise.
PHOTO/DESIGN
49 East 21st Street
New York, New York 10010
A monthly publication covering photography as used in the design and
advertising fields. (This magazine may be out of production. -- LWB)
PHOTO DISTRICT NEWS
49 East 21st Street
New York, New York 10010
The monthly trade magazine of photography which takes it name from the
area of New York City in which it is located.
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PHOTOGRAPHERS FORUM
Published by Serbin Communications
511 Olive Street
Santa Barbara, CA 93101
(805) 963-0439
Features upcoming photographers & students as well as interviews
with established professionals. -- Steven Lunetta, [email protected]
PHOTOGRAPHY IN NEW YORK
PO. Box 20351
Park West Station
New York, New York 10025
A bi-monthly guide to photographic exhibitions and galleries. Private
dealers, auctions, and photographic books are also covered.
PHOTOSTOCKNOTES
PhotoSource International
Dept. H
Pine Lake Farm
Osceola, WI 54020-5602
(715) 248-3800
Internet: [email protected]
A monthly newsletter consisting of 8 tightly-knit pages designed to keep the
busy stock photographer up-to-speed on the changes in this evolving field.
Free sample issue available. -- Bill Hopkins, [email protected]
SHOTS
P.O. Box 38149
Dallas, TX 75238
Shots is one place you can see your work in print, as well as the
work of others. No ads, just images and a bit of writing. Membership is
$20.00 per year and a best bet if you love to see photographs.
-- Steven Lunetta, [email protected]
POPULAR PHOTOGRAPHY
1633 Broadway
New York, New York 10029
The world's largest monthly publication devoted to photography and covers
new equipment, pro advice, contests, and more.
THE RANGEFINDER
1312 Lincoln Boulevard
Santa Monica, California 90406
(310) 451-8506
A monthly magazine devoted to the technical aspects of photography and
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includes equipment reviews and coverage of new products.
SHUTTERBUG
Box 1209
Titusville, Florida 32781
A monthly magazine featuring perhaps the most extensive equipment and
product advertising in the photo community, complimented by news,
features, and reviews.
SHUTTERBUG'S OUTDOOR & NATURE PHOTOGRAPHY
Box 1209
Titusville, Florida 32781
A new monthly photo magazine has just premiered (in the USA anyway).
It is called _Shutterbug's Outdoor & Nature Photography_. Using the
same size and format of _Shutterbug_ magazine, it concentrates on the
same outdoor themes as Outdoor Photographer (though not as erudite in
tone) and the review style is similar to Shutterbug. Premier issue
covers tripod selection, new color films, backpacks, trip planning,
filter usage, etc. -- John McCormack, [email protected]
TAKING STOCK
(was: STOCK PHOTO LETTER)
by Jim Pickerell
110 Frederick Avenue
Rockville, Maryland 20850
A quarterly newsletter for stock photographers.
VIEW CAMERA
2774 Harkness St.
Sacramento, CA 95818
(916) 441-2557
[email protected]
A bi-monthly for View Camera enthusists.
ZONE VI NEWSLETTER
Published by Zone VI Studios/Fred Picker
Newfane, VT 05345-0219
Concise and practicle information on photography, art and life.
They make the most bitchen field camera ever. If you don't use their
meters, you aren't getting good exposures. [I am not affiliated with
them-just love their stuff.] -- Steven Lunetta, [email protected]
and some more from various sources ...
Exposure
3721 A Webster
San Francisco, CA 94123
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Exposure is a new magazine for and about the unknown photographer trying
to make names for themselves. We feature the work of the professionals of
tomorrow. If you have a photo story, great stand alone, or even an idea
for a story, let us know. We are interested in covering all the issues of
the up and coming photographer.
Afterimage
Visual Studies Workshop
31 Prince Street
Rochester, NY 14507
(716) 442-8676
Fine art photography issues
Photo Techniques
Preston Publications
PO Box 48312
7800 Merrimac Avenue
Niles, Illinois 60714
or PO Box 779,
Mt. Morris, IL 61054
formerly Darkroom & Creative Camera Techniques
SEE
Membership
The Friends of Photography
250 Fourth Street
San Francisco, CA 94103
published by The Friends of Photography,
Or, you can e-mail them at [email protected]
or you can call at 415-495-8517
DoubleTake
P.O. Box 1918
Marion, OH 43305-1918
ph: 708-965-0566
fx: 708-965-7639
6 issues/year subscription is $19.95
mostly documentary, but it has very well
written articles and beautiful photographs
================================================================================
Note 31.5
-< X-Ray machines at airports >-------------------------------------------------------------------------------Some logic surrounding X-ray inspections of films
Yesterday I saw a science magazine on public television wich, among other
topics, had a report on airport x-ray machines. It was quite short, but with
some math and commom sense I was able to deduce the following.
_MODERN_ airport x-ray machines use such low radiation doses, that you would
have to pass something through them 1000 (one thousand) times to equal the
(average) annual "natural" radiation background. "Natural" in this case
includes the radiation found in houses due to the decay of radioactive isotopes
found in the building-material.
Assuming (for simplicity) a year had 10,000 hours (actually its less than
8,800) this would mean that one pass through a _MODERN_ x-ray machine (stressed
here for the last time ... I _know_ that there are old ones with higher doses
out there) would correspond to a ten hour normal storage for a film (at
sea-level).
At an altitude of 10km (33,000 for "non-metricists") --- quite a normal
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cruising altitude for airplanes --- the radiation intensity is increased a
hundredfold compared to sea-level. Repeating the calculation from above leads
to the equivalent of one pass through the x-ray machine every six (!!) minutes
if you are travelling at this height. In other words; if you're taking a long
distance flight, your films will get the equivalent of TEN (10 !!) passes
through the airports x-ray for EVERY HOUR of the flight.
So I wouldn't blame the airport security for exessive fogging of film.
Lead-shielded bags probably aren't much of a help either, since the atmospheres
radiation stopping capability is equivalent to a three foot thick lead shield,
and you've already got three fourths (3/4) of the atmosphere below you at 10km
height. Who would pay the air fare for a hundred (hundreds of ???) pounds of
lead just to shield her or his films ?!?
**************************************************************************
Klaus Bagschik, Radioastronomisches Institut der Universit"at,
Auf dem H"ugel 71, D-53121 Bonn, Germany
e-mail: [email protected]
Tel.:
+49-228-73-5658
-3643
Fax:
+49-228-73-3672
**************************************************************************
================================================================================
Note 31.6
-< Testing Shutters the SIMPLE way >------------------------------------------------------------------------------->does anyone know of a simple way to test the times a shutter delivers?
Here's an approach which I have used successfully for years; it requires a
little bit of electronics and a little bit of programming.
Wire a light-sensitive transistor to the push-button input of an Apple II,
then program an assembly-language routine to loop and count as long as the
transistor sees light. An Applesoft routine can call the machine-language
routine, and translate the loop count into actual opening times.
Naturally I don't have the thing here with me and can't tell you what
resistors etc. I used, but the response of the system extends to measure flash
duration - 1/10,000 or better.
I used a similar circuit to make an enlarging timer, which ran entirely in
Applesoft; this requires a circuit to control 110v AC from 5v DC TTL. A piece
of Rubylith over the B&W tv makes a darkroom monitor.
Dan Johnston, [email protected]
.........................................................................
If you have an old 33-1/3 record player, put a small **wheat-grain** light
bulb on the center and another anyplace on the rim. Wire them up to a
battery. Place on the floor in any dark room. Place camera on a tripod,
looking down, over the center. Turn on player. Expose test roll at different
shutter speeds. develop and print. Measure the ***angle*** of the arc.
Convert to fraction of a second. (What shutter speed makes a complete
circle?)
Fred, <[email protected]> "Dr. Fred J. Gunther"
...........................................................................
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>>>>> On 19 Jul 1995 11:26:03 -0400 (EDT), [email protected] said:
> There is also an enlarging timer on the market that may also be
> used for checking shutter speeds (both fp and leaf). The lens or camera
> Is placed over the sensor while light from the enlarger illuminates
> the *whole* A friend has one and uses it regularly for this purpose.
^
there is a hole in the housing of the timer.
> An investment in a new timer may allow you to do both (tho' not at the
> same time) I will inquire (enquire ?) of the make and model and post to
> the list later.
I believe it's the MetroLux II timer you're talking about (because I just
got one). I tried doing a shutter test with just my enlarger light, but it
wasn't bright enough for the sensor to register. I don't really plan on
doing much shutter testing (if any), but it did come along with the rest of
the package (note that the cost of the Calumet meter is something less than
1/4 of the timer cost).
Pete, [email protected] (Pete Bergstrom)
.........................................................................
Calumet sells (sold?) a relatively inexpensive shutter speed checker that
operates exactly as the phototransistror + oscillator + counter + display
circuit I described in an earlier post. When we bought one for our school
the price was in the $75 range. It may be more practical to buy something
like this preassembled and tested than to start from scratch. Often the
attraction of home-built devices is not so much the cost savings but the
pleasure of making something. Calumet's phone number is 800-CALUMET
andy, [email protected]
.........................................................................
Depending on what is meant by "simple" there are two systems that are usually
referred to when one considers testing exposure times "ala cheap". The first
is the turntable system which is useful for speeds up to about 1/60 second or
so. It has the disadvantages mentioned in several earlier posts. For shorter
exposure times one needs a standard with a shorter time base. Television sets
can be used as shutter testing devices but only for the shorter exposure times
starting with about 1/30 second although with a bit of "logic" one can probably
make a fairly good estimate of even 1/15 of a second as long as shutter is not
off by more than 25% or so.
The best type TV to use is a B&W one. It should be tuned to a "clear" channel
where you don't get noise just a plain screen. The TV sets lay down 15,750
lines on the screen (NTSC standard) in one second. It does it in 1/60 second
"fields" or screenfulls each consisting of 262.5 lines. They are laid down
going from top to bottom.
Basically the idea is that if you make an exposure at 1/1000 second you would
count about 16 lines in a vertical direction. If you use a leaf shutter the
exposed "band" made up of however number of lines the set was able to scan onto
the TV faceplate will be horizontal and if you use a FP shutter then the band
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will have a tilt to it depending on the speed at which the curtains are moving
and how close the camera is to the screen. (Assumption is made that the
camera's shutter is made to travel perpendicular to the motion of the TV
scannning action).
You can also roughly estimate the width of the FP shutter slit and appreciate
the fact that its width increases as the shutter moves from one side of the
gate to the other.
BTW ... for the turntable test a variation is to use photo paper placed on the
turntable and have the light project through the lens onto the whirling paper.
You can retrieve an article about this by sending e-mail to: [email protected]
placing in the Subject: line this: article_shutter_testing$txt and SEND in
body.
andy
o o 0 0 o
o Andrew Davidhazy, at RIT's Imaging and Photo Tech Dept
\/\/\/\/\/\/
[email protected]
High Speed Photography Lab
________|
|__________________________________________________________
............................................................................
Hmmm, ... this probably isn't quite what you had in mind, but maybe you
can adapt it for your needs.
Some years ago I wanted to determine the delay I needed to take
pictures of soap bubbles in "mid-pop" --- the contraption being rather
fragile I didn't dare to take it out of the house (I had built it at
home). The only thing that came to my mind as a useful "time standard"
was the turntable of my record player ...
What I did was to tape a bright marker onto the turntable which I set
at 45 rpm and have the contraption release two flashes while taking a
picture of the table; being able to measure the angular separation of
the two marker images to one degree I achieved an accuracy of roughly
1/270 sec --- which won't be enough for you ...
What _YOU_ could do would be to buy a synchronous motor that
rotates at the line-frequency --- 60 cps in the US ((or an integer
part thereof ?!? ... depends on motor)), attach a black cardboard
disk firmly to the motors axle and punch a small hole into the disk
close to its circumference (for best results). Now put a (very ?!?)
bright light underneath the disk and turn the motor on; the disk
-- and with it the brightly lit hole -- now rotates 60 times a second.
If you take a picture of the disk and are able to measure the angular
extent of the streak caused by the hole to only five degrees, you can
obtain an accuracy of 1/4320 sec ... this would mean 25% uncertainty
at 1/1000 sec shutter speed ...
DRAWBACKS: -only usable for speeds faster than 1/60 sec.
(if slower use turntable (if if still exists))
-no good for focal plane shutters !!
-need to wait for developed film
(( If the motor only turns with 30 rps or 20 rps the other figures
are reduced accordingly ))
Side view:
camera
/\
||
||
stray-light shield
file:///C|/faq.html (297 of 555) [7/19/2002 3:46:29 AM]
||
\/
=================
|
===========
----------------|------------ --- <-- Disk
|
\
--------\______Hole
^ ^ ^
| MOTOR |
^ ^ ^
| | |
--------| | |
(LIGHT)
(LIGHT)
If this should be useless, I hope it was at least an inspiration
=8-)
Klaus
**************************************************************************
Klaus Bagschik, Radioastronomisches Institut der Universit"at,
Auf dem H"ugel 71, D-53121 Bonn, Germany
e-mail: [email protected]
Tel.:
+49-228-73-5658
-3643
Fax:
+49-228-73-3672
**************************************************************************
If you can find one, such a device can be easily constructed from an old record
turntable. Assuming you can trust the rotation speed of the turntable, then all
you need to do is paint an old LP with black and white index markings. The bad
news is that such a device requires you to expose a roll of film to actually do
the test. Expose with flash.
Joe Angert, St. Louis Community College
================================================================================
Note 31.7
-< Copying Artwork with Tungsten Lights discussion >------------------------------------------------------------------------------->Which chrome film would you recomend for the most accurate representation for
>the purpose of photographing an artists portfolio. I will be photographing with
>lights and due to the bulbs I know I will have to use tungsten slide film. The
>plans are to use a camera fixed to a location with a zoom so I can switch art
>sizes without having to move the camera/lights back and fourth. On both sides
>of the camera it is planned to place two diffused light sources (unbrella &
>pannel) at 45 deg. to the art. The art will be hanging on a wall with a matt
>black background. Any helpful hints?
Ektachrome EPT. The copy setup you are using may give you problems with your
fixed camera/lights. Ideally use electronic flash for copies of artworks as
this will give you the most neutral rendition. Use polarising filters on the
flash units (tungsten lights will melt them) and on the camera. Cross polarise
the light to the point where, with the modelling lights turned on, you see a
shiny object placed on the surface of the artwork (e.g. a coin) turn black
when you rotate the camera's polar filter. Umbrellas will increase the
posibility of reflection. Reflections will kill the colour in the original and
you will be amazed at the colour saturation of copies done with polarised
light. Transparency film gives the best possible colour range and saturation
too.
James McArdle , Photography Lecturer, Latrobe University, Bendigo
file:///C|/faq.html (298 of 555) [7/19/2002 3:46:29 AM]
[email protected]
...............................................................................
Your setup should work fine with a tungsten balanced film. I have been using
Kodak's 64T and been quite happy with the results. I prefer it to the faster
stuff, due to its finer grain and better reciprocity characteristics. For
similar reasons, I would avoid using a conversion filter with daylight film,
unless you can get fairly short exposures (1/8 or less) at about F/8 (for flat
art).
Be sure to take your reading from a grey card, bracket, and make notes. If you
have time, you can shoot a test roll of a few subjects and base a full run on
how it turns out. Depending on the materials of the portfolio, you might
consider a polarizer. Examine the subjects through it while rotating it to see
if it has any effect.
An alternative is Kodachrome 40. It has a slightly different look to it, but
might be what you like. It is nominally balanced for 3400 degrees, rather than
the more common 3200, but I have exposed it with normal tungsten lights and no
filter for all but the most critical subjects. It has the disadvantages of
being more expensive, a bit harder to find, and taking longer to process, since
it must be sent to a Kodak lab.
Nathan Prichard, Kentucky Historical Society, [email protected]
...............................................................................
I like Ektachrome 50 Professional (Tungsten) film although if you can live with
the inconvenience of getting Kodachrome processed Kodackrome 40 is a very good
film IMHO too. If _all fails_ and you can not get Tungsten film you can come
fairly close to appropriate color reporduction if you use Daylight film and
place a Tungsten to Daylight conversion filter over the lens. This costs you
about two stops of speed. The filter is a 80A if your bulbs have a color
temperature of 3200 degrees K or an 80B if they are of 3400K quality. The
former are generally simply high wattage household lamps while the latter
are specially made photo lamps with generally a rather short operating life.
Althgouh many textbooks recommend lighting at 45 degrees I find this a bit
steep and prefer to light material at more like 30 - 35 degrees with each of
the lights aimed at the opposite edge of the work that the lamps are on. This
makes for more even lighting in my opinion. Another scheme, described in
Kodak's booklet on Copying and Duplicating, is to aim the lights at the side
of the original nearest each of the lamp and the lamps aimed at 45 degrees to
the surface.
The black matt background is a good idea. It will help keep flare down and
contrast up. Use of a polarizer on camera was suggested earlier and typically
needed to control surface reflections somewhat. Also suggested earlier, use of
polarizers on both lights and camera is the only way to extinguish most
reflections (if you really want to do that). Using polarizers will call for
longer times or larger apertures than if you did not use one. Use of of
polarizers over both lights and camera lens makes the problem even worse.
Although since you are using a tripod you should have no real problem dealing
with this.
Andy, [email protected]
file:///C|/faq.html (299 of 555) [7/19/2002 3:46:29 AM]
..............................................................................
>I am going to be taking photographs of flat artwork ... any pointers?
For any significant amount of work of this sort, you might consider
investing in a sturdy copystand and a set of consistent tungsten lights. For
the stand, you'll need one which will permit centering of the camera over
the largest piece you anticipate copying. Watch out for bright metal parts
such as the column which will reflect light onto the subject.
I'm using using an old Polaroid MP-4 with the 35 mm adapter as my copy stand
for such projects. For illumination, I use the quartz modelling lights on a
pair of small Speedotron Brownline heads nounted on light stands and
positioned so that all parts of the original subject receive equal
illumination. The positioning is generally the most time consuming part of
the shoot, and once the lights are set, they're left in place 'til the
client is satisfied. I use a handheld incident light meter in the center of
the subject and at each of the corners. I've come to trust the meter I have
(Minolta Auto IVF) as being right on for transparencies so I generally don't
bracket unless trying a new film.
I shim the copystand so that the board is level, then adjust the camera so
that the film plane is level and parallel to the copy board.
I always add polarizing sheets in front of the light sources to enhance the
color saturation. If glare remains a problem I add a polarizer to the lens
as well, meter TTL off a gray card and bracket.
I try to avoid glass over the original subject because of glare and because
glass itself has a slight greenish tint to it. However, when the shot must
be made thru glass, I add a piece of black mat board to the set up. I keep
on hand a piece about 18" x 20" with hole in the center just large enough
for the barrel of the taking lens to slip through. I put the lens barrel
thru the hole then add the lens shade to hold it in place. The mat board
eliminates reflections from the camera, chrome fittings on the cable
release, my hand, and the ceiling.
For this type of work, I'm using tungsten balanced Ektachrome 64 (both 35 mm
& 4x5) which allows long exposures (i.e. >1 sec) without the need to correct
for reciprocity and which treats the colors of the original properly. Also,
coninuous lighting rather than flash permits easier adjustment & shows
before the exposure is made any relflection problems that need to be corrected.
Written by Roy C. Zartarian
================================================================================
Note 31.8
-< What is a TLR in reference to a camera? >------------------------------------------------------------------------------->I use a 35 mm camera but am interested in understanding cameras with different
>design features. I have seen references to "TLR" cameras with implications
>that they are different than, say , "TTL" cameras. Would anyone be willing to
>provide an explanation of the difference.
The abbreviation TLR stands for "Twin Lens Reflex". This camera has two
lenses, one for viewing, which is reflected upward onto the groundglass
file:///C|/faq.html (300 of 555) [7/19/2002 3:46:29 AM]
or into a prism, and the bottom lens which is fixed in place, in most
cameras, that take the pic. The advantage of a TLR over and SLR is that
the mirror is stationary, so there is no mirror slap or blackout when the
picture is taken.
Examples of TLR cameras include Rolleicord and Rolleiflex, the Minolta
Autocord, the Mimaya TLR's, which have interchangeable lenses unlike the
others, and the old Yashica-Mats. Most of them take 120 size film, so
they are considered MF, or medium format, cameras.
I have an older Rolleicord, and I absolutely love it.
John Thompson <[email protected]> Canton, Ohio
.........................................................................
A "TLR" means Twin Lens Reflex. The design consists basically of two cameras
stacked on top of each other with the top one used for viewing and composition
and focusing through a fixed aperture lens. The viewing lens and the taking
lens are matched in focal length and focusing mechanism so as you focus the
image projected on the groundglass of the top one you automatically bring the
bottom into focus as well. Since bottom lens is equipped with a leaf shutter
the camera syncs with electronic flash at all speeds.
TLR's were (are?) by far the preferred machine for wedding photographs and many
photographers owe their livelihood to one of these cameras.
TLR's come (came?) in most varieties of film formats but the most common is the
2 1/4 film delivering square format pictures. There is a bit of a parallax
problem considering the slight separation between viewing and taking lens but
this can be adjusted for or sort of predicted with cropping marks in the
viewfinder or moving masks in the viewfinder that adjust as the lens board is
racked out.
The most famous example of the TLR is the Rolleiflex and a prolific user of
this camera was Fritz Henle who published several "Guide to Rollei Photography"
books. The most famous 4x5 TLRs are by far the ones made by Peter Gowland right
here in the USA! (I think ... and if so one of the very few remaining
professional camera manufacturing operations in the US with Hulcher and Globus
being a couple more). BTW, Peter Gowland is a prolific "cheesecake" or pin-up
girl photographer. (I don't think it is PC to say this but he has made a good
living at glamour and "boudoir" photography for many years).
Another workhorse is the Mamiya C- series like the C-3, C-33, C-330 etc. This
one system became famous partly because it allowed for interchangeability of
lenses. You had actually to "interchange" two lenses at a time but the camera
survived many years until it was just recently discontinued. The Rolleiflex was
discontinued some years back but a top-notch model of the camera has been
recently reintroduced.
There was at least one 35mm model made many moons ago ... the Bolsey 35mm TLR.
well, the story of the TLR is much too large to be told in a single post and
you may have noticed some of my comments left the door wide open for follow-ups
and additional commentary or criticism.
file:///C|/faq.html (301 of 555) [7/19/2002 3:46:29 AM]
andy, [email protected]
...............................................................................
How about this: TTL => Through The Lens metering. This metering concept
illustrates that the camera's metering is based on the same light that
the film will see. TLR => Twin Lens Reflex, as opposed to SLR. This means
that the camera has two lenses, one for viewing the image, and the other
in which the film actually sits behind. I suppose that TLR camera can
utilize metering through the upper lens, while the actual picture taking
is based on the lower lens. This eliminates any potential vibrational
noise that may be generated from flipping of a mirror commonly used in
SLR cameras.
If I am wrong about any of the above, then I must be human. Take care.
Brae, <[email protected]>
...........................................................................
TLR stands for Twin Lens Reflex. You probably have seen them. It's a
medium format camera that utilized a lower lens for the shutter, while the
upper lens is for the viewfinder.
Steve, [email protected]
.........................................................................
Ok thats an easy one TTL is Thru the Lens
TLR is Twin Lens Reflex
SLR is Single Lens Reflex.
I own a TLR and Love it, it's quiet and Takes Gorgeous Shots. Problems
with it are that you are viewing thru a lens OTHER than the Taking lens
Forget to take the cap off the Taking lens and you get Blank Photo's.
Also Parrallax Problems come up when doing Closeups.
Used TLR's abound and are IMO a PERFECT way to try Medium Format since
they are readily available and fairly inexpensive. You can go from the
Bottom of the Barrel Russian Lubitel which I've seen advertised in
Shutterbug for as little as $25 to Rolleiflex's for $500 or more.
The only TLR I know of that has Changeable Lenses is the Mamiya C-330
I suggest a good Rolleicord or Minolta Autocord or a Yashicamat 124g
Tho My TLR is a LOW end Yashica "D" that I paid $60 for and which takes
pix as crisp as my Mamiya 645
From: [email protected]
================================================================================
Note 31.9
-< Another note on 2nd curtain sync >------------------------------------------------------------------------------->what is the effect of using a 2nd curtain sync flash? I think i understand
>how it works mechanicaly, but I don't know what kink of effect it is used
>for or when it is used.
file:///C|/faq.html (302 of 555) [7/19/2002 3:46:29 AM]
When there is little or no ambient light present it makes not much
difference which scheme you use, conventional "X" sync or 2nd curtain
sync (more properly referred to as "tailflash synchronization" because
when applied with leaf shutters since these do not have a second curtain
the term is inaccurate). The only difference will be that if you happen
to be using a long exposure time the picture will obviously not be
taken at the time you trip the shutter but at some later time, just
before the shutter closes.
OTOH, if there is a significant amount of ambient light, this will
cause "ghosting" of the moving subject (basically the moving subject
appears blurred) attached to a sharply rendered image of the subject
caused by the short duration of the flash relative to the long
exposure time given by the shutter.
Under this condition, if the flash goes off immediately upon the
shutter opening, the moving subject's blurred image will recorded
subsequent to the flash going off and thus will appear to precede the
sharp image (relative to the apparent subject motion) in the final
print or transparency. This happens with conventional X sync or 1st
curtain sync.
The blured image can be used to suggest motion. In the above instance,
however, the subject will appear to be moving backwards since our
society's artistic convention is that for an illustration to suggest
that the subject is moving in a given direction it must have the blur
behind it, showing up in that side of it from which it is _coming_ and
NOT on that side towards which it is _going_.
So, the conventional sync scheme shows the blur in the "wrong" side of
a moving subject. Here is where TAILFLASH sync (or 2nd curtain sync in
case of FP shutters) comes in. If one first records the blur due to
ambient light with a relatively long exposure time, and just previous
to the shutter closing one pops a short duration flash, the sharp
image will appear at the end of the blur and on a print the blur will
appear to "trail" the moving subject, just like artists have convinced
us this effect shgould look like.
In certain instances one can make the action proceed backwards and use
conventional X sync to show believable subject motion "forwards" but
with human motion or destructive events this is most often not
possible. At least not convincingly so.
BTW... the combination of ambient and flash exposures was much
exploited by photographers such as Philip Leonian and Ben Rose.
Andy, at RIT's Imaging and Photo Tech Dept., [email protected]
................................................................................
>I am interested in the effects of slow-synch flash (blur) but have not
>been able to achieve this with my EOs-1 or Elan. Is there a special switch
>or do I just set the shutter speed for the lowest possible to get a blur?
>Appreciate any advice...
I am not sure your cameras have "2nd curtain sync" but even so intersting
file:///C|/faq.html (303 of 555) [7/19/2002 3:46:29 AM]
things can be done by simply combining flash with high levels of ambient
illumination. Make sure you have a good dark background and overexpose the
ambient exposure by two or more stops. This is best done by working everything
on manual settings. Determine what aperture is required to properly expose your
subject by flash. Then adjust the ambient light level so that the particular
aperture that you determined will result in a 2-3 stop overexposure of the
moving subject that you are wanting to photograph at the chosen exposure time.
Now, if you only have conventional sync on your camera make the action proceed
backwards (in order for it too look like it is going forwards!). If you have
second curtain sync (more appropriately referred to as "tailflash" sync) just
make everything move normally.
The reason for the overexposure of the moving subject is that since the subject
does not remain on the same piece of film throughout the exposure, it becomes
its own shutter and if you did not compensate the blur associated with it would
be significantly underexposed and you'd think the effect was not working
properly. The overexposure needed by the moving subject also is the reason that
you want the action to proceed against a dark bacground because it is
motionless and thus will, in fact, be overexposed (but since it was dark to
begin with that should not bring its density up enough to matter). Getting the
right combination of flash/ambient exposure is not exactly predictable and
tests are recommended.
andy, [email protected]
================================================================================
Note 31.10
-< Photo Related URLS - HUGE list >-------------------------------------------------------------------------------HUGE list of photography related URLS on a worldwide basis. This list
is from my Netscape bookmark file. It includes many references I have
got from other people and lists around the WWW. If you have a list you
are welcome to take what you want from here. I have edited out most of
the non-photo stuff and converted it to plain text. There will be
mistakes in this; also some sites will have disappeared since I
visited them. There are also a few (not many) I haven't yet got round
to trying. I'd be happy to receive any additions and corrections to
this list.
(see my pictures on FIXING SHADOWS:
http://fermi.clas.virginia.edu/Niepce/peter-m.pl )
************************************************************
PHOTOGRAPHY RELATED URLS - (c) PETER MARSHALL - 15 July 1995
MAGAZINES etc
http://www.scotborders.co.uk/photon/ - Photon Home Page
http://sunsite.unc.edu/nppa/photon95.html - Photon Express - US Nat
Press Photo Newsletter (text)
http://www.novalink.com/pei.html - Photo Electronic Imaging Mag
http://www.trincoll.edu/tj/trincolljournal.html - Trincoll Journall Multimedia mag
file:///C|/faq.html (304 of 555) [7/19/2002 3:46:29 AM]
http://pni4news.wwa.com - PNI's homepage
http://www.padd.press.net/ - Press Association
http://www.mindspring.com/~frankn/atlanta/ - The Atlanta
Photojournalism Seminar
http://sunsite.unc.edu/nppa/photon95.html - Photon Express US Nat Press Photo Newsletter (text)
http://www.newsusa.com" - News USA home page
http://enterzone.berkeley.edu/enterzone.html - Enterzone zine
http://www.awa.com/w2/intimations/i-1.3.html -photography and poetry Websters Weekly
LISTS OF PHOTO SITES
http://math.liu.se/~behal/photo/ - Behal photo list - Bengt's Photo page
http://www-swiss.ai.mit.edu/philg/photo/ - Philip Greenspun's Photo Page
gopher://gopher.blackstar.com:70/1 - Gopher: Blackstar
gopher://gopher.panix.com:70/11/Photography - Gopher: panix com
http://www.phantom.com/~kadvocat/keri.html - Keri's list of photosites etc
http://www.cris.com/~mppa/ - MPPA's World Wide Web home page
http://sunsite.unc.edu/nppa/dig95/diggallery.html - NPPA index to photo sites
http://www.ksu.edu/~camk/photography.html - Photography on the Web
http://sapphire.surgery.wisc.edu/paul.html - Paul's Photo list
http://www.lib.cortland.edu/photo.html - WWW page for Photo related WWW
pages.
http://www.nmsi.ac.uk/nmpft/hotlist0.htm - NMPFT Bradford list of Photo
Sites
http://www.art.net/ - Art on the Net
GENERAL LISTS useful for finding photo related information
http://info.cern.ch/hypertext/DataSources/bySubject/Literature/Overview.ht
ml
Art sources
http://www.rsl.ox.ac.uk/bardhtml/ - BARD (Boolean Access to Remote Databases)
http://www.catalog.com/bhunter/welcome.htm - Brent's Internet Jumpstation
http://www.netcenter.com/ - The Interactive Yellow Pages(Tm)
http://www.openmarket.com/info/internet-index/current.html - Internet Index
http://www.hw.ac.uk:8080/libWWW/irn/irn.html - internet rewources guide
- Herriot Watt Univ
http://www.kingston.ac.uk/directory/directory - Kingston Univ list of
interesting sites
http://www.tribal.com - Tribal Voice- listing of Web sites
http://www.eff.org/pub/Net_info/Guidebooks/Everybodys_Guide/Updates/Internet guide updates
http://www.yahoo.com - Yahoo - A Guide to WWW sites
http://www.goshen.edu/~floyd/index.html - Some Internet Search Tools
http://www.interpath.net/home/search.html - WWW Launch Pad
http://www.albany.net/~wcross/all1srch.html - All searches front end
http://cuiwww.unige.ch/meta-index.html - Meta-Index
HISTORICAL
file:///C|/faq.html (305 of 555) [7/19/2002 3:46:29 AM]
gopher://marvel.loc.gov/11/global/sci/astro - Library of Congress, (usa),
http://lcweb.loc.gov/homepage/lchp.html - Library of Congress World Wide
Web Home Page
http://www.webcom.com/~gwalker/" - Digital Daguerreian Archive
MUSEUMS
http://cmp1.ucr.edu/exhibitions/cmphome2.html - California Museum of
Photo
http://www.zdepth.com/cia/ - Cleveland Institute of Art
http://www.iuma.com/iuma-bin/imagemap/artnet-map - The Internet Arts
Museum Main Floor
http://www.macom.co.il/museum/phooto-1 - Israel Museum Photography
http://www.nmsi.ac.uk/nmpft - NMPFT Bradford home page
GALLERIES / HOME PAGES A-F
http://bookweb.cwis.uci.edu;8042/AdamsHome.html - Ansel Adams
http://www.cea.edu/robert/ - Robert Altman's Homepage
http://www.netwest.com/~aerial/ - aerial photos of Arizona
http://arthole.com/ - Art Hole
http://www.artn.nwu.edu/gallery.html - (Art)^n Laboratory
http://www.ashe.miami.edu/ab/artweb.html - Artweb Miami
http://www.mindspring.com/~baird/apg/index.html - Atlanta Photo Group Gallery
http://bookweb.cwis.uci.edu:8042/Jazz/jazz.html - Avery'sJazz Photography
http://www.dircon.co.uk/maushaus/azario/azario.html - Stefano Azario editorial / ad work - from London
http://www.onramp.net/~hbarker - Hal Barker, Korean War
http://www.art.net/Studios/Visual/Troyb/home.html Troy Bennett
http://data.ns.ccf.org/kositss/w.4 - Berlin Fashion
http://www.ashe.miami.edu/ab/webme.html - Adam Block
http://www.cs.ucl.ac.uk/bbrace/12hr.jpeg - 12 hourly jpeg image
sequence: B Brace
http://www.teleport.com/~bbrace/bbrace.html - Brad Brace
http://metro.turnpike.net/J/job/index.html - Jochen Brennecke Photoshop images
http://www2.msstate.edu/~celeste/cbgallery.html Celeste Brignac
http://www.xmission.com/~photofx/ Ron Brown
http://199.4.33.215/stuart/RJB/RJB.html - Randy J Brown photos
http://www.dfki.uni-sb.de/~butz - Andreas Butz homepage
ftp://ftp.netcom.com/pub/jc/jca/photos/photopage.html - Gallery - JC
http://internetcafe.allyn.com/davidc.html - Clumpner Photographic Archive
http://www.gonix.com/fcollins/welcome.html - Fred Collins - The Light
Fantastic
http://www.jcu.edu.au/dept/Art_and_Design/exhibition_nov94/EXHIBITION.html
- James Cook University exhibition
http://fermi.clas.virginia.edu/~ds8s/julia-md/jmd-1.html - JMD Photos
http://www.iia.org/~deckerj - John Decker - Covington's Homeless
http://www.intac.com/~jdeck - John Decker - Carnival workers
http://cs.williams.edu/~95als/dephocus/ - Dephocus WWW site
file:///C|/faq.html (306 of 555) [7/19/2002 3:46:29 AM]
http://www.picture.com/Alan-Dorow.html Alan Dorow - Animal Crackers
http://www.earthlink.net:80/~rdunn/ - Rick Dunn
http://www.mtn.org/~ddb" ADD_DATE="802992870 - David Dyer-Bennet
http://the-tech.mit.edu/Gallery/gallery.html - The Edgerton Center's
Online Photo Gallery
http://usa.net/~davef/ - Dave Faulkner Gallery
http://www.art.net/Studios/Visual/Fenster/ritofab_Home/fenster.html - D. Fenster
http://atm21.ucdavis.edu/~fishman - Schuyler Beth Fishman
http://fermi.clas.virginia.edu/~ds8s/ - Fixing Shadows
http://branch.com/artists/artists.html - Gallery of Artists,NYC ...
GALLERIES /HOME PAGES G-N
http://www.mindspring.com/~galbrair/galbraithhomepage.html - Rob Galbraith
http://www.slip.net/~chuckg/ - Chuck Gathard home page
http://www.wimsey.com/Generality/Generality.html" - Generality Home Page
http://www-swiss.ai.mit.edu/philg/photo/ - Philip Greenspun
http://www-swiss.ai.mit.edu/samantha/travels-with-samantha.html Travels with Samantha {Philip Greenspun)
http://www.teleport.com/~illum. - David R. Griffith
http://166.90.202.17/portfolio.html - Chris Gulker homepage
http://amug.org:80/~avishai/morephoto.html - Avishai Halevy photographs
http://www.interaccess.com/users/bhphoto/gallery.htmlGrafks - Brian
Heston - CyberGrafks
http://www.mindspring.com/~royal/cnphoto.html - Ron Hewitt, Olympic
construction photos in Atlanta
http://infosphere.com/aspen/Hiser/DavidHiser.html - David Hiser
http://liberty.uc.wlu.edu/~aholick - Arne S. Holick-Kuhlmann
http://www.ncsa.uiuc.edu/SDG/Software/Mosaic/Docs/old-whats-new/whats-new1294.html
Hot Pictures - from Russia
http://ns.southern.edu/people/rphowell/angi.html - pictures - R P Howell
http://www.cs.vu.nl/~pmhudepo/ - Patrick MJ Hudepohl
http://www.infi.net/pilot/extra/gallery/gallery.html - Infi net gallery
http://holly.colostate.edu/~shane/photo.html - Shane Iseminger's
Photojournalism on line
http://www.dataflash.it/made.htm - Italian fashion and creativity
http://www.mcs.net/~rjacobs/home.html - Photography HomePage - Richard
Jacobs
http://198.88.177.10/MCC-3-3-0.html - Brian K. Johnson
http://www.lehigh.edu/~aj02/digital_wave.html - Lisa Johnston
http://www.eunet.fi/nepal/ - Petri Kaipiainen, photos of Nepal
http://www.access.digex.net/~keithj/2Sight.html - Keith's Second Sight Photojournalism (US)
http://www.euronet.nl/users/shorty/index.html - Hans de Kort
http://liberty.uc.wlu.edu/~aholick - Arne Kuhlmann, photojournalism
http://www.rt66.com/swest/labane/labane.html - figure-in-landscape
Edward LaBane
http://ironbark.bendigo.latrobe.edu.au/staff/photo/photo.html - La Trobe
Univ Australia Home Page
file:///C|/faq.html (307 of 555) [7/19/2002 3:46:29 AM]
ttp://sensemedia.net/sprawl/35060 - Daniel Leighton's 3D Gallery
http://ted.ele.madison.tec.wi.us/art/start1.html - Students work Madison Area Technical College
http://www.intac.com/~jdeck/tahra - Tahra Makinson-Sanders, two photo
documentaries
http://edu-gw.isy.liu.se/~y94chrma/ - Chris Maluszynski
http://www.nwlink.com/~gmanasse - Geoff Manasse
http://aleph0.clarku.edu/~bmarcus/home.html - b marcus home page
http://fermi.clas.virginia.edu/Niepce/peter-m.pl - Peter Marshall Carnival and London buses
http://www.dircon.co.uk/maushaus/Mousefile.html - Maushaus virtual
gallery - London
http://www.webcom.com/~zume - Rajiv Mehta (5 photographers)
http://www.sirius.com/~meatyard - Meatyard Photopage
http://konpeito.bekkoame.or.jp/~misawa/ - Yasushi Misawa - Japanese
journalist
http://www.cris.com/~okyeron/ - Steven Noreyko
http://nyweb.com/mainmenu.html - New York Web Main Menu
GALLERIES / HOME PAGES O-Z
http://sunsite.unc.edu/otis/ - OTIS Home Page
http://antics.com/mpearl.html - Pearl St. Online Gallery
http://www.bradley.edu/exhibit/index.html - Peoria Digital Photo Galley '94 in
Peoria, Il
http://www.bradley.edu/exhibit95/ - second annual Peroia Art Guild and
Bradley University Digital Photo Show
http://www.phantom.com/ - Phantom - photography
http://www.homepages.com/~photoweb/ - PhotoWeb,
http://www.picture.com/ - picture gallery
http://white.nosc.mil/art.html - Planet Earth Home Page - Art and Photography
http://www.abc.se/~m8976 - Jannis Politidis home page - Stockholm
http://www.commerce.com/procko/ - Steve Procko
http://www.tis.com/Home/Personal/Ranum/Page.html - Marcus J. Ranum
http://hammers.wwa.com/hammers - Steve Rapport Photography
http://riker.ps.missouri.edu/RicksPage.html - Rick Reed
http://www.rit.edu - Rochester Institute of Technology
http://ultb.rit.edu/~rckpph - School of Photographic Arts and Sciences
at Rochester Institute
http://web.metronet.com/~arose/home.html - Alen Rose, news photographer
http://interport.net/~sr - Stacy Rosenstock - Stacey's Home Journal
http://www.mtn.org/~ddb - San Francisco, photography
http://130.212.13.58/infoarts/kevin/kevmiddle.html - SF Camerawork
http://www.webcom.com/~zume/JW.InTransit/InTransit.html - Sanfrancisco
transit pics
http://www.crl.com/~whisper/SaraTOC2.html - Sara
http://myth.com - Mythopoeia, by Suza Scalora
ftp://ftp.netcom.com/pub/ss/sschwab/schbase.htm - Bill Schwab photo home page
http://www.umich.edu/~cjericks/gallery/gallery.html - figure photographer
Jody Schiesser
file:///C|/faq.html (308 of 555) [7/19/2002 3:46:29 AM]
http://www.mindspring.com/~atlphoto/schwarz.html - Michael Schwarz Down's syndrome, Religious extremeists, Fungicide
http://dana.ucc.nau.edu/~sps - Stephen Schweitzer home page
http://cs.williams.edu/~95als/dephocus/ - Adam Seligman
http://clark.lcs.mit.edu:80/~rsilvers/rsilvers.html - Rob Silvers photo, ray tracing etc.
http://avocado.pc.helsinki.fi/~janne/photo/photo.html - Janne Sinkkonen's Page
http://http1.brunel.ac.uk:8080/~is93swc/ - Sophia's Home Page
http://gertrude.art.uiuc.edu/ludgate/the/place/place2.html - Joseph
Squier, University of Illinois
http://www.magic.ca/magicmedia/hypervision/hventer2.html - The Florida
Series. Steve Stober
http://ziris.syr.edu/ - Syracuse University Art School
http://www.rt66.com/austin/ - Southwest USA -Fine Art Images
http://gertrude.art.uiuc.edu/ludgate/urban_diary/page1/diarypage1.html urban diary page 1 (Joseph Squier)
http://BizServe.com/thirdeye/ - Third Eye PhotoWork Collection.
http://www.cs.arizona.edu/people/bmtong/photo.html - bmtong photos
http://nermal.santarosa.edu/~mfaught/2dog.html - Two Dog Gallery
http://www.cnct.com/home/webmaker/rain.html - Natsuko Utsium Rainforest photos
http://128.250.224.11/bensimages/bensindex.html - Victoria Australia Pix - Ben
http://www.fullerton.edu/viscom/vishome.html - VisCom, Cal State University
http://sunsite.unc.edu/otis/pers/Volk_O.html - Oleg Volk
http://www.digimark.net/galaxy/ - Jason Ware Astrophotography
http://www.aaj.com/aaj - WorldWide Gallery
COMPUTERS and PHOTOGRAPHY
http://www.fa.indiana.edu/~s491 - The Computer and Photography
http://www-swiss.ai.mit.edu/philg/how-to-scan-photos.html - Greenspun's
Guide to Scanning Photos
ftp://ftp.netcom.com/pub/hsc/Kais_Power_Tips/pc_tips/ - Directory of
Kais_Power_Tips for pc
http://the-tech.mit.edu/KPT/KPT.html - Kai's Power Tips and Tricks for
Photoshop
http://www.cs.cmu.edu:8001/afs/cs.cmu.edu/user/rwb/www/gamma.html explanation about monitor gamma
TECHNICAL & FAQs
http://agno3-si.clemson.edu/CC/ALT.PHOTO.PROC.FAQ.html - ALt processe FAQ
http://www.usask.ca/~holtsg/photo/faq.html - 2nd Alt Proc FAQ
http://www.dopig.uab.edu/ - DOPIG Home Page
http://www-swiss.ai.mit.edu/philg/photo/framing.text - Notes on framing
http://aragorn.solutionsrc.com/PHOTOWORKS/pw9.htm - Professor FilmWorks'
Camera Tip of the Month
http:/www.ip.net/shops/1GlamourPhoto - GlamourPhoto posing guides
http://www-swiss.ai.mit.edu/~philg/photo/hand-coloring.html - Guide to
Hand Coloring Photos
http://www.mta.ca/ - MAIL ORDER ADVICE TO ALL
file:///C|/faq.html (309 of 555) [7/19/2002 3:46:29 AM]
gopher://atlas.chem.utah.edu:70/11/MSDS - Material Safety Data Sheets (from BYU)
http://www.cs.arizona.edu/people/bmtong/ - Nikon FAQ
http://www.cs.arizona.edu/people/bmtong/ - Nikon Flash
http://www.siu.edu/departments/ctc/apartphp/ - Photoshop work by students at
Southern Illinois University
http://www.cs.arizona.edu/people/bmtong/photo/ - Rec photo FAQ
http://www.chemie.unibas.ch/default.html - Scientic Research - restoring
old film etc
http://www.galaxyphoto.com/galaxy - Astrophotography
http://www.ashe.miami.edu/ab/photo.html - B&W instruction page)
http://www.ios.com/~badger/ - Canon EOS FAQ
ASSOCIATIONS
http://sunsite.unc.edu/nppa/index.html - National Press Photographers Assoc.
http://tronic.rit.edu:80/Minolta/ - Minolta Users Group
BUSINESSES
http://www.adobe.com/Apps/Photoshop.html - Adobe Photoshop
http://www.netwest.com/~aerial/ Arizona Aerial Photographs
http://akebono.stanford.edu/yahoo/Business/Corporations/Photography/ Business:Corporations:Photography
http://infoweb.net/rockaloid/ - Rockland Colloid
http://www2.interpath.net/gallimore/ - Cramer Gallimore Studio
http://www.intnet.net/Tampa/Market/Photo.html - Bruce Hosking's Pages
http://www.kodak.com/homePage.shtml - Kodak
http://bluedog.ucdavis.edu/ucdis/title_pg.htm - Illustration Services Server
http://www.designlink.com - Photo Group, Professional
http://www.nets.com/sfworkshop.html - Santa Fe Workshops Home page
http://www.solutionsrc.com/PHOTOWORKS/ - Seattle FilmWorks
http://pni4news.wwa.com/ - Seymour image browser (subscriber)
http://www.aztec.co.za/slpn/slpn_hp.html - SouthLight PictureNet Home Page
http://aztec.co.za/slpn - South Light Agency - S Africa
http://atnet.co.at/viennaslide/ - Viennaslide, online picture service
http://infoweb.net/rockaloid/ - Rockland Colloid at the InfoWeb Mall
http://www2.helix.net/~cameras/pacific.html - Pacific Camera Co
(secondhand collectible cameras - US)
http://www.demon.co.uk/arena/hagerty/index.html - Hagerty's Used
Cameras, (UK)
MISCELLANEOUS </H3>
http://www.ircam.fr/divers/arts-deadlines.html - Arts Deadlines [wossat?]
http://cannes.zds.softway.worldnet.net - Cannes Film Festival
http://franceweb.fr/cine/cannes - Cannes Film Festival - The alternative
http://www.cs.ucl.ac.uk/misc/uk/london/london_photos.html - London Photos
http://math.liu.se:80/~behal/photo/ - Photographic Walking Tours in
London
http://www.comlab.ox.ac.uk/archive/ox/photos.html - Oxford photographs
Views around Oxford
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http://www.usgs.gov/ - Spy satellite photos
http://www.cityscape.co.uk/users/ae37/index.html - Vive La France!
.............................................................................
and here is another one....
Below is a partial list of World Wide Web photo and photo-related sites.
If there are any you would like to include, please e-mail the WWW address
and I'll post it at a later date.
-http://166.90.202.17/
(Chris Gulker, professional photographer)
http://bookweb.cwis.uci.edu:8042/Jazz/jazz/html (Jazz Photography of Ray Avery)
http://bookweb.cwis.uci.edu:8042/AdamsHome.html (Ansel Adams)
http://cmp1.ucr.edu (California Museum of Photography, University of California)
http://cris.com/~Mppa/
(Michigan Press Photographers Association)
http://gertrude.art.uiuc.edu/ludgate/the/place/place2.html (Joseph Squier,
instructor, University of Illinois)
http://holly.colostate.edu/~shane/photo.html
(Shane Iseminger)
http://iia.org/~deckerj
(John Decker, documentary photo projects)
http://infosphere.com/aspen/Hiser/DavidHiser.html
(David Hiser)
http://sunsite.unc.edu/nppa
(National Press Photographers Association)
http://usa.net/~davef
(inspirational photographs for sale)
http://www.aztec.co.za/slpn/slpn_hp.html (SouthLight PictureNet, PJ in Africa)
http://www.designlink.com
(Designlink, San Francisco. Design, Graphics,
Photo, Portfolios Online)
http://www.fullerton.edu/viscom/vishome.html (VisCom, Cal State University)
http://www.ios.com/~badger/
(Canon EOS FAQ)
http://www.kodak.com
(Eastman Kodak Company)
http://www.mindspring.com/~atlphoto/schwarz.html (Michael Schwarz, PJournalist)
http://www.mtn.org/~ddb
(San Francisco, photography)
http://www.onramp.net/~hbarker (Korean War project)
http://www.scotboarders.co.uk/photon/photon.html (Photon, a WWW photo mag, UK)
http://www.slip.net/~chuckg
(Chuck Gathard)
http://www-swiss.ai.mit.edu/philg/photo/me.html (Phillip Greenspan's favorites)
http://www.teleport.com/~bbrace/bbrace.html
(Brad Brace)
http://www.trincoll.edu/tj/trincolljournal.html
Note 32.01 -< Manufacturers and Distributors of Rotating Panoramic Cameras >-------------------------------------------------------------------------------This is a list of US manufacturers and distributors of rotating camera type
panoramic cameras. Please send info on others to: [email protected] to update
this file.
Hulcherama - Charles Hulcher Company
909 "G" Street
Hampton, VA 23661-1717
804-245-6190
Globuscope - Globus Bros. Studio
44 W. 24th Street
New York, NY 10010
212-243-1000
Alpa Rotocamera - HP Marketing
SpinShot
file:///C|/faq.html (311 of 555) [7/19/2002 3:46:29 AM]
- Karl Heitz
216 Little Falls
Cedar Grove, NJ 07009
201-857-0171
Roundshot -
Camerama
131 Newton Street
Weston, MA 02139
800-274-5722
34-11 62nd Street
Woodside, NY 11377
718-565-0004
Noblex (swing lens type camera)
Kamerawerke Noble GmbH
Bismark-Strasse 56, D-01257
Dresden
Tel: 49-351-28069
Fax: 49-351-2806392
[email protected]
(klaus peter knoll)
================================================================================
Note 32.02
-< Several observations on rotating panoramic cameras >------------------------------------------------------------------------------->Last week some one posted a message regarding a friends camera that makes
>10" x 4' negs. Sounds great! B&H advertises a similar camera called a
>"Spin-shot" I think it uses 35mm film and it rotates on its tripod mount
>to include a full 360 degree pan on each exposure. I think the negs it
>makes are the width of 4 reg frames. Has anyone ever used or seen this
>type of camera or a similar one from another manufacturer? Any comments
>or shared experiences would be appreciated.
I have two SpinShots ... bought them just before the price climbed to $2 per
degree. The camera is interesting but has many major limitations. At least mine
do. Fixed aperture for one ... so adjusting for lighting conditions is done by
using different film speeds (pretty novel, eh?)(I guess you also could use
fastest film plus ND filters). The camera is made of plastic and the plastic
latch on both of mine broke and cameras are now held together by tape or rubber
band. The film speed through the camera does change as the take up spool
diameter increases causing slight blurring at the ends of the film. Often this
is not really noticeable except under high magnification.
MUCH better is the Globuscope. A 35mm rotating panoramic camera also Made in
USA (as far as I know) and it is an all metal camera (except where metal would
not normally be used ... like lens!) and the camera's rotation rate can be
changed, it has a high quality lens, and various adjustments. The price tag is
in the $2,500 area however.
At the larger format end there is the Hulcherama. A camera made in Hampton, VA
by the Charles Hulcher Company. It is an excellent camera in my opinion. It is
set up for Mamiya 645 lenses but can be custom made to accept others (at higher
price). It can be readily ordered with provision to accept 35, 45 and 80mm
lenses. It takes 120 or 220 film. It has a pinch-drive system so film speed is
uniform. The rotation rate can be varied over a large range and the slit-size
is also adjustable giving you a large variety of exposure times. The price for
the camera body alone is in the $5,000 range.
There is the Alpa Rotocamera. A GREAT camera set up for a 100mm lens I think
and I also believe it has the capability for rising/falling lens. The camera is
a marvel of mechanical engineering and also made in Europe. It's price is high.
Beyond these there are the various Roundshot cameras made in Switzerland I
file:///C|/faq.html (312 of 555) [7/19/2002 3:46:29 AM]
think. They come in 16mm, 35, 2 1/4 and even larger formats. They are
jewel-like in contruction and operation and their price tag reflects this. The
company that makes these cameras also now makes a "strip" enlarger which one
lab in Florida has purchased. Although amateurs such as myself have built such
enlargers much earlier (like 1975 or so) this is the first commercial example
of such an enlarger (although Itek built such a machine for the Air Force in
the late 60's I believe).
hmmmm ... did I leave anything out? If so just give me another "kick"
;-)
oh, yes .... if you want to read about "strip" cameras and home-made panoramic
and peripheral cameras you can find several articles at the
[email protected]
mailserver site.
Just send e-mail to this address and say ARTICLES$txt in the subject line to
get a table-of-contents and brief synopsis of the articles available for the
asking along with instructions on how to retrieve them. These are only text
files so you'll have to imagine the pictures. The part of the site you will be
accessing is devoted to the PhotoForum mailing list (which is shared by/with
our school's program files) and if you make an error in requesting anything you
will be sent by default a file that tells you all the "stuff" available at the
site.
If you actually go looking in this place I hope you find something of use to
you! BTW ... some of this stuff is also available by anonymous FTP at
vmsftp.rit.edu
under
pub/ritphoto/photoforum
>I don't believe their strip enlarger is that new; if I recall correctly,
>they had this enlarger on the PhotoKina in Cologne (Germany) in '92 or '90.
>But I think Seitz itself was the only company at that time that could do
>those prints on a economic basis....and the number of labs in Europe having
>one right now is also quite limited I guess....similar to the camera itself.
very true ... OTOH Phil Foss of Eastman Kodak had made one in the early 80's
and mine was operating in the mid 70's I believe. The Itek enlarger was
designed for enlarging 70mm or 5" film that was exposed in aerial strip cameras
based on a design by Sonne of Chicago Aerial Industries who made the camera for
General Goddard I believe. Sonne and del Veccio who was a pioneer in
photofinish camera development in the mid 1930's cooperated in amking the
aerial version of the photofinish camera. This is pretty much the same as
making pictures of a wallpaper or the houses along a street (which I did over a
mile long stretch of a local avenue a couple of years ago... but which the
Globus brothers did almost 10 years ago by holding their camera still allowing
the handle to rotate)
>BTW, Seitz makes also pseudo (or 'inverse'?) panorama camera's, where the
>objects turns around instead of the camera. This is usefull for an 360
>degree image of a teacup for example. Another variant is a camera that runs
>parallel to the object, to make a distortionfree image of a wallpaper for
>example.
Indeed in the late 1800's at the British Museum strip cameras (or variations
thereof) were already used to make what some people call "rollout" photographs
of rotating vases and urns, etc. These pictures being possibly better referred
to as "peripheral" photographs. There was a company in England that made the
file:///C|/faq.html (313 of 555) [7/19/2002 3:46:29 AM]
R.E. Engineers Periphery Camera which was actually a traversing back that could
be fitted to a 4x5 camera. The function of the moving back was to move the film
at a steady pace past a slit. The device also came with a precision turntable
and the whole thing could be mounted on a lathe-bed or similar for high
precision peripheral work onto sheet film. The price was very high but several
labs (notably the FBI lab in Washington) purchased one of these units. Steve
Morton in Australia made a back like this independently.
Also, Omega Timing (also Swiss?) has developed the technique of photofinish
photography to an "art" having not only film cameras, but also sheet film and
Polaroid cameras.
BTW, please note that this is not to diminish or otherwise dismiss Seitz's
contributions to the field but their products can probably more accurately be
called refinements to a very high order of precision of techniques that are
almost as old as photography itself. Maybe a better way to take these snippets
of info is as a brief review of the history of strip cameras! ;-)
And before I forget, there are many "amateurs" (lovers of the craft) who have
developed exquisite cameras and made wonderful photographs with them. I will
try to compile a listing of these individuals as best I know them but until the
project gets going I wanted to mention just this one:
Steven Morton, works at Monash University in Melbourne, Australia. His e-mail
address is [email protected]
Others whose name popped into my head: Phil Foss, Jim Lipari, Charles Hulcher,
and E.O. Goldbeck. And among the swing-lens panoramic camera makers and
photographers: Tom Yanul, who works in Chicago and makes his own VERY large
format cameras that are maybe 20 inches tall by 6 feet long and cover 130 to
150 degrees or so.
================================================================================
Note 32.03
-< Comments on panoramic photography requirements >------------------------------------------------------------------------------->if the film required for a panorama is in mm = 2 x Pi x focal length (mm)
>then if the camera does not rotate about its film plane but on a disk so that
>the film plane is say 100mm off the centre of rotation, should this additional
>radius be added to the fl of the lens to determine the correct film length??
The answer is no (but with caveats). As long as the subjects you are
photographing are very far away like when doing scenics it does not matter
much that the camera rotate about an axis other than the rear nodal point.
Once the subjects start to be closer than "infinity" then this factor needs
to be taken into account. The problem is that while you will be properly
correcting for subjects that are closer than infinity, those objects at
infinity now will be reproduced in distorted fashion. What is happening is
that the image velocity is no longer uniform for near and far objects.
If the camera rotates about the proper point there is no relative motion
between the image and the film ... they both move equally fast. If the
camera rotates about an axis closer to the film plane or even possibly
behind the film plane the consequence is that images of nearby objects will
file:///C|/faq.html (314 of 555) [7/19/2002 3:46:29 AM]
appear to move past the slit in the camera faster then those far away. If
you do not compensate they will be reproduced "compressed" horizontally. The
objects at infinity will hardly change in speed no matter how far the camera
is from the axis of rotation. You could (theoretically) use the earth as the
device to turn the camera and make a panoramic photograph of the heavens
with not problem.
From Applied Photography by Arnold, Rolls and Stewart:
" The use of moving film can be extended by modification of the drive speed to
systems with rotation about other axes, in which the image is not stationary.
As in the periphery camera such a drive can be correct for only one particular
magnification; linear distrotion and possibly unsharpness resulting at other
image scales. The correct film drive speed (Vf) to match the image movement is
given by the formula:
Vf = 2piR [d-(d-v)(1+m)]
where
R is the rotational speed of the
d is the distance of the axis of
(this is "negative" if axis of
v is the image distance from the
m is the magnification
camera
rotation _in front_ of the image point
rotation is behind film plane)
lens rear nodal point
Note that when d = v (ie the lens rear nodal point is on the axis of rotation)
Vf = 2piRd
(or 2piRv)
and is independent of magnification.
Also, when m is small, as with distant objects:
Vf = 2piRv
and is independent of the axis of rotation."
... does this answer your question?
;-)
Andrew Davidhazy, [email protected]
..............................................................................
From: Kevin Mackenzie <[email protected]>
Subject: Re: Panoramic Cameras
Thanks very much for your reply; It does indeed answer my question. I am
thinking about mounting an old rangefinder upside down on a wooden disk. This
disk could then rotate on a bearing above another disk with an elastic band
around it to act as a tire. The film rewind knob could ride on this tire. Now
by having the circumference of the disk and tire sized appropriately, the
correct length of film could be drawn past a slit at the film plane. I assume
that if I do not correct for the off axis-nis of the film plane then distortion
would be greatest very close to the camera and much less as distance increases.
I can tolerate this and any of my slighty overweight (and wide) friends could
be positioned slightly closer to the camera than the thin folk :-)
file:///C|/faq.html (315 of 555) [7/19/2002 3:46:29 AM]
A panoramic photo of the stars would be really great. Perhaps this could be
done from earth near one of the poles during winter (night). This could be
done with a regular camera and tripod if the speed of film rewind could be
accurately controlled (over a 24 hour period), the earth would provide the
rotation.
..............................................................................
================================================================================
Note 32.04
-< Pointers on drying Fiber Based papers >-------------------------------------------------------------------------------Your print drying method is important because it affects the final surface.
The simplest but slowest technique is air-drying. You must first remove
surplus water from back and front print surfaces with a rubber squeegee.
Leave prints on absorbent material such as cheesecloth or photographic
blotting paper, face up for RC paper, face down (to reduce curl) for hardener
treated fibre prints. Pet them on a line with plastic clothes pects at top
and bottom - fibre prints in pairs back to back, RC prints singly. Drying may
take several hours at room temperature.
To speed up drying of RC prints, hand them in a heated film drying cabinet, or
blow them over with a hair dryer (termperature not exceeding 85C. Better
still, pass the wetted prints through an RC dryer, designed to deliver dry
prints in about 10 seconds.
For fast drying of fibre prints, have a flat-bed or rotary glazer, which uses
canvas to press the paper against a heated (usually polished chrome) metal
surface. Placing the back of the print towards the heat gives a final picture
surface similar to air drying. However, to get a glazed finish with glossy
fibre paper, you squeegee it face down on to the chrome sheet, so the gelatin
supercoat sets with a matching mirror-like finish when dry. Unless this is
done, glossy fibre papers will dry semi-matt. You can at any time remove the
glaze by thoroughly resoaking the fibre print and then drying it faced the
other way. (Avoid hot-glazing other fibre paper surfaces, and RC prints of
any kind. The former take on ugly patches of semi-glass, the latter will melt
at 90C or over and adher firmly to the metal and canvas.)
Manufacturers of premium fine-art fibre papers recommend air drying unless you
are glazing glossy. The fact is, anything touching the emulsion during drying
is a potential source of damage. There is always a risk, when using a glazer
for other fibre paper surfaces, that the canvas will either mark the final
emulsion finish, or chemicals previously absorbed from drying insufficiently
washed prints will transfer into your print. However, this is still the best
drying method for thin-base prints, which tend to curl badly if air-dried
instead.
Not all my own work. mary :)
From: [email protected] (Mary Thomas)
..............................................................................
================================================================================
Note 32.05
-< Dividing 1 gal E-6 for small batch processing >--------------------------------------------------------------------------------
file:///C|/faq.html (316 of 555) [7/19/2002 3:46:29 AM]
For those wishing to make up Kodak E-6 chemistry for small batch processing
in 500 ml tanks, I offer the following dilutions for each of the steps that I
used successfully for years (while processing one to 2 rolls at a time by hand)
Add to
200 ml of water at room temperature...
First developer
Reversal Bath
Colour developer
A
B
Pre-bleach
Bleach
A
B
Fixer
Final rinse
86.55
29.56
ml
ml
83.03
29.56
84.47
ml
ml
ml
236.5
ml
7.378 ml
59.125 ml
3.68
Note: ALWAYS add colour developer A BEFORE B, and ALWAYS to a dilution with
water. NEVER add the A to the B or there will be a precipitate that will not re
dissolve. When purchasing the 1 Gallon Kit I also used to purchase an extra
bottle of first developer as well as an additional colour developer to extend
the number of rolls I could process from the kit (the bleach being the most
expensive part).
Take note that after the carefully added aliquot (gotta love that word eh?) of
the E-6 chemistry to the 200 ml of water at room temperature .....
BRING THE VOLUME UP TO 473 ml,
(1 pint US)
This one pint of developer will process a total of 4 rolls of film
The first two rolls will be developed for 7 minutes at 100 deg F and the
second two rolls should have the time extended to 7.5 minutes.
Ken Sinclair RBP., Agriculture and Agri-Food, Canada Research Centre,
Lethbridge, AB. Canada, (403) 327-4561. x 306, [email protected]
================================================================================
Note 32.06 -< High Speed Photography Sample Exam - Questions and Answers >-------------------------------------------------------------------------------This is a sample exam associated with a high speed photography course in the
Imaging and Photographic Technology program in the School of Photographic Arts
and Sciences at RIT. It is given in the early parts of the course (when some
of the topics have not yet been covered) so that students will get a general
idea of what the style of the final exam will be. In some cases a variation on
these same questions is included in the final, in others the questions are not
included in the final. Following the distribution of these questions the
instructor briefly goes through the answers to each question but does not
dwell on the theory that has not yet been covered since this willbe eventually
covered in the course. Listed below first are the questions by themselves and
below them are the questions followed by the answers.
1 What is the exposure time necessary to limit blur in a subject moving at
file:///C|/faq.html (317 of 555) [7/19/2002 3:46:29 AM]
10 feet per second to 1/100 of an inch at the film plane if you used a
50mm lens and the subect was 2000mm from the camera?
2 Photographing a TV screen with a Focal Plane will produce a raster
pattern that is similar to that produced by a Leaf Shutter shutter when
what condition is established?
3 What is the limiting or defining criterion that defines whether a
photographic print appears sharp or not?
4 If an electronic flash circuit is able to handle the change, then what
is the effect of doubling the voltage of the circuit?
5 What is the effect on the duration of the flash given the same conditions
as in the previous question?
6 Why is it not practical to measure the duration of an electronic flash at
50% output levels?
7 What kind of synchronizer would you use to photograph the splash produced
by a falling drop of milk and why?
8 A synchronizer that depends on detecting the sound emitted by an even
does not allow you to photograph what portion of the event?
9 A streak camera is capable of measuring several factors associated with
subjects. Name at least three of them.
10 What steps would you take in order to make measurements based on a streak
camera, or any other camera for that matter, independent of magnification.
11 A picture is made at an exposure time of 1/100 second with a 35 mm camera
equipped with a leaf-shutter and a 50mm lens. The picture that you make of
a 1 foot square subject appears as an image that is twice as long as it is
tall. From this you can deduce that the subject was moving at what speed?
12 In a streak camera in which the film is moving at 35,000 mm per second a
subject that moved at right angles to the film motion leaves a 45 degree
trace across the width of the film. How fast was the image of the suject
moving?
13 In order to calibrate anything you first need what?
14 With a focal plane shutter, exposure time is defined by what relationship?
15 Assuming
a 100 mm
the same
Describe
that two photographs of the same moving subject are made one with
lens and the second with a 50mm lens. The prints show the subject
size. One photograph, made with a 100mm lens, exhibits motion blur.
the appearance of the second photograph concerning the same effect.
16 The maximum framing rate at which a camera can usually operate is a
function of how fast the film can be advanced and the shutter recocked in
the camera plus another factor. What is this "other" factor?
17 These are a series of images made sequentially with a camera making
file:///C|/faq.html (318 of 555) [7/19/2002 3:46:29 AM]
1000 pictures per second of a rotating fan. Assuming that the fan turns
less than one revolution between pictures, at what rate was the fan turning
in RPM?
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source of sound will add about how much delay to the next photograph?
19 The slope of the edge of a shock wave is a function of the speed of sound
in the gaseous medium in which a missile moves and the...
1 What is the exposure time necessary to limit blur in a subject moving at
10 feet per second to 1/100 of an inch at the film plane if you used a
50mm lens and the subject was 2000mm from the camera?
The answer to this question is based on Image/Subject distance relationships.
If the lens is a 500 mm lens and the subject was 2000 mm from the camera then
the Subject is 2000/50 or 40 times bigger than the image made by the lens. If
the blur can only be 1/000 inch in the camera, at the Subject this translates
to 40/100 or .4 inch. So the Subject can only move .4 inch during the exposure.
Since the amount of Blur one gets is determined by taking the Subject Speed or
Velocity and multiplying by the Exposure Time this can be rearranged so that
Exposure Time required is equal to Blur Allowed divided by Subject Speed.
so, required ET = .4 inches divided by 120 inches per second
or 1/300 second
2 Photographing a TV screen with a Focal Plane will produce a raster
pattern that is similar to that produced by a Leaf Shutter shutter when
what condition is established?
A TV set delivers 15,750 lines of information on the screen per second. That is
there is 1/15,750 second between lines. Theoretically one should only "see"
15.75 lines of the screen if one makes a picture at 1/1000 second. This is more
or less so but due to afterglow of the phosphors in a practical situation it is
a bit off. Anyway, the lines are laid down from top to bottom. If photographed
with a leaf shutter one sees a horizontal "band" 16 or so lines wide. If
photographed with a Focal Plane shutter lined up to travel horizontally with
respect to the scanning direction will show a diagonal "band" still 16 lines
wide at each end.
If the FP shutter travels parallel to (either with or against) the direction
of motion of the CRT scan the result will be a pattern very similar to the one
produced by the leaf shutter but it will depict fewer or more lines than should
be counted as a result of the exposure time given by the shutter.
3 What is the limiting or defining criterion that defines whether a
photographic print appears sharp or not?
file:///C|/faq.html (319 of 555) [7/19/2002 3:46:29 AM]
for imperceptible blur in a print the defining criterion is the maximum
acceptable size of the circle of confusion under the given conditions.
4 If an electronic flash circuit is able to handle the change, then what
is the effect of doubling the voltage of the circuit?
Potential power or watt.second rating of a flash is given by 1/2 Capacitance
times Voltage Squared therefore doubling the votage quadruples the power
5 What is the effect on the duration of the flash given the same conditions
as in the previous question?
Half-peak to half-peak duration is specified as Capacitance times Resistance
divided by square root of two. Therefore upping the voltage does not affect
duration.
6 Why is it not practical to measure the duration of an electronic flash at
50% output levels?
This gives an "inflated" estimate of action stopping ability of an electronic
flash. It basically neglects light emitted by the flash before and after the
light level is at the 50% output level. It assumes that underexposure of a
scene by one stop (50%) does not produce a useful record when we all know that
one can underexpose by several stopsand still get some sort of an image.
The result typically is that highlights of a moving subject appear
significantly more blurred than shadow areas since the light level has to drop
many stops lower than full intensity before it is low enough to not produce
significant exposure to the film.
It is much more "practical" to estimate the duration of electronic flashes at
25% or even 10% percent output levels.
7 What kind of synchronizer would you use to photograph the splash produced
by a falling drop of milk and why?
A "dark" synchronizer. A drop passes through a light beam changing a "light"
condition into a dark one. This is detected by a circuit which causes a flash
to fire. It helps if the signal from the "dark" synchronizer is delayed a
(variable) fraction of a second to give the drop a chance to fall to a more
useful location than the light beam which is used to detect its passage.
If the "dark" sync trips an SLR some measure of dealy is introduced by the
camera itself since they have an inherent delay before releasing the shutter
curtains and since the flash does not fire until the first curtain has actually
travelled across the frame even more delay is potentially available. The actual
pattern of the splash can then be adjusted by raising or lowering the impact
surface.
8 A synchronizer that depends on detecting the sound emitted by an even
does not allow you to photograph what portion of the event?
The beginning. By the time you hear it, the beginning of an event is over.
9 A streak camera is capable of measuring several factors associated with
file:///C|/faq.html (320 of 555) [7/19/2002 3:46:29 AM]
subjects. Name at least three of them.
Elapsed Time
Velocity
Acceleration
Frequency
Simultaneity
10 What steps would you take in order to make measurements based on a streak
camera, or any other camera for that matter, independent of magnification.
Include a scale or subject of known size in the picture and then make
measurements within the picture based on the reproduced size of this scale.
11 A picture is made at an exposure time of 1/100 second with a 35 mm camera
equipped with a leaf-shutter and a 50mm lens. The picture that you make of
a 1 foot square subject appears as an image that is twice as long as it is
tall. From this you can deduce that the subject was moving at what speed?
If the subject is 1x1 foot and it appears to be twice as long as tall then the
Subject would be 1x2 feet. Subtracting out the first foot (the size of the
subejct itself) gives an indication that the subject moved 1 foot during the
exposure time or in 1/100 second.
therefore, if it moved 1 foot in 1/100 second it was moving at 100 feet/second
12 In a streak camera in which the film is moving at 35,000 mm per second a
subject that moved at right angles to the film motion leaves a 45 degree
trace across the width of the film. How fast was the image of the suject
moving?
For every unit of film that moved through the camera one unit of image moved at
right angles to the direction of motion of the film. Therefore the veolcities
of the film and image were the same. So, 35,000mm second was the image speed.
13 In order to calibrate anything you first need what?
a standard
14 With a focal plane shutter, exposure time is defined by what relationship?
The ET of a focal plane shutter is equal to the width of the slit divided by
the rate at which the slit moves.
15 Assuming
a 100 mm
the same
Describe
that two photographs of the same moving subject are made one with
lens and the second with a 50mm lens. The prints show the subject
size. One photograph, made with a 100mm lens, exhibits motion blur.
the appearance of the second photograph concerning the same effect.
The two pictures will essentially be identical in terms of motion blur but
since the one made with the 50 mm lens will have to be blown up twice as much
as the one made with the 100 mm lens it will appear "grainier".
16 The maximum framing rate at which a camera can usually operate is a
function of how fast the film can be advanced and the shutter recocked in
the camera plus another factor. What is this "other" factor?
Assuming one is not allowed to start making a picture before one is done making
the previous one the ultimate limiting factor in terms of recording frequency
file:///C|/faq.html (321 of 555) [7/19/2002 3:46:29 AM]
is the EXPOSURE TIME.
17 These are a series of images made sequentially with a camera making
1000 pictures per second of a rotating fan. Assuming that the fan turns
less than one revolution between pictures, at what rate was the fan turning
in RPM?
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2
3
4
5
6
7
8
Note that the fan blade turns 180 degrees between picture #1 and picture #5
That means that 5 - 1 pictures, or 4 pictures were required to record these
180 degrees. Picture #1 is simply the reference mark. Therefore the fan
turned 180 degrees in 4/1000 or 1/250 second. That is 180 x 250 or 45000
degrees per second which is 7500 RPM
18 Moving a sound synchronizer's microphone 1 foot further away from the
source of sound will add about how much delay to the next photograph?
Since sound travles at about 1000 feet per second, 1 foot stands for 1/1000
second.
19 The slope of the edge of a shock wave is a function of the speed of sound
in the gaseous medium in which a missile moves and the...
velocity of the missile itself. Thus the angle of the shock wave (which can
be relatively easily recorded with a shadowgraph system) can be used to make
a good estimate of the speed of a missile.
Andrew Davidhazy, at RIT's Imaging and Photo Tech Dept, [email protected]
================================================================================
Note 32.07
-< The Royal Photographic Society - Info >------------------------------------------------------------------------------->I would like to take up the Licentiateship of Royal Photography Society,
>But I do not have the Address . If you could get it to me I'd appreciate it.
The best source of information is a 16 page special feature 'Gaining RPS
Licentiateship' in the July/August 1994 issue of The Photographic Journal
(ISSN 0031-8736), (which is the Society's Journal).
The appropriate application form for Licentiateship can be obtained from:
Ms Carol Agar
The Royal Photographic Society
The Octagon
Milsom Street
Bath BA1 1DN
UK
Phone:
0225 462841
file:///C|/faq.html (322 of 555) [7/19/2002 3:46:29 AM]
(The RPS, like many UK institutions, is not (yet) on the Net!)
There is also an information booklet available from the above, giving full
details of the requirements for the Licentiateship and for all the
categories of each RPS Distinction.
From: Mike Ware <[email protected]>
================================================================================
Note 32.08
-< More panoramic photography material ... >------------------------------------------------------------------------------->I am thinking about trying to make a simplified ciircuit camera. For those
>who do not know a circuit camera is one where the lens rotates and "paints"
>an image across the film as it rotates. These were used a lot in the past
>to take panoramic pictures. I know of only one currently made.
The "cirkut" camera is undergoing somewhat of a revival in terms of new models
being available. Not in the large formats of the past but in 16mm, 35mm,
120/220, and 70mm. There was even a recent attempt at a 5" sized one.
Hermann Seitz of Switzerland (?) manufactures several models starting from
16mm. Alpa makes (made?) the Rotocamera that is either 120 or 70mm. On the
American side there is(was?) the Globuscope in 35mm and the Hulcherama in the
120 size. Globus also made an adapter for a 4x5 camera that used 5" roll film.
I believe they made 1 or two of them! And who can forget the one made by
Corrales Cameras, the 35mm SpinShot, a plastic wonder at $ 720 for 360 degrees?
There may be a couple more models as well.
There is a very active group of amateurs and professionals that use, rebuild
and build "cirkut" type and swing-lens panoramic cameras. It is the
International Panoramic Photographers Association.
I myself am one of those amateur builders and experimenters. My cameras are all
35mm. I have made them based on rewinding the film to move the film past a slit
and have also made some based on advancing the film with the sprocket drive and
providing power to the sprocket either through motors or by direct coupling
with a gear or friction drive arrangement. I have also published several
articles on the application of "strip" cameras from use in the panoramic mode
as well as the peripheral, photofinish and aerial/terrestrial scanning modes.
>I am interested in the physics of how the images is made by the rotating
>lens and how the exposure time can be calculated. How do you relate
>the speed of rotation of the lens to an actual shutter speed?
Basically the length of any panoramic photograph is governed by the focal
length of the lens you choose. Once the length is known then the time to cover
the desired angle will determine the rate at which the film must move throught
he camera. Once this rate is known, then the width of the "shutter" slit
divided by the rate of film motion gives the exposure time. Once this is known
then you take a meter reading and determine the aperture required for the given
exposure time and then you take your picture.
Roughly speaking the camera is typically rotated about a point located near the
file:///C|/faq.html (323 of 555) [7/19/2002 3:46:29 AM]
rear nodal point of the lens or somewhat closer to the film than this point.
This causes the image formed by the lens to remain stationary in space behind
the lens even as the camera is turning. The function of the film is to simply
move at the same rate as the image seems to be left behind by the moving slit
so that it will remain stationary with respect to the image. It is amazing how
well the system works.
To determine exposure time this is one approach.
For example: Assume you will make a panoramic camera of this kind using a 24mm
lens as the camera lens. A full 360 degree shot with it will require
2 x pi x f
mm of film
or 2 x 3.1416 x 24 = 150mm
now say you want to cover the 360 degrees in 10 seconds, then
Film Velocity in camera =
150mm / 10sec
=
15mm/sec
if you then know that the stationary shutter slit in the camera is 1mm in width
Exposure Time = slit width / film rate
1mm / 15mm/sec =
1/15th second
As I said this is one way to do it. There are others but they all lead to the
same place.
There are two unusual home-built panoramic cameras that to the best of my
knowledge are of a unique design. One was built by Phil Foss of Kodak and the
other by myself. They both operate by placing their image on film rotating at
the film plane instead of moving in linear fashion. While Phil's typically is
designed to cover a full 360 degree circle, mine can place a 360 degree pan on
less than a 360 degree tyrn of the film. This allows the shaping of the
resultant panoramic images to be made into conical shaped products such as flat
sunhats, umbrella decorations, skirts, or lampshades.
The history of the evolution and development of the camera was presented at a
meeting of the SPIE, the International Society for Optical Engineering. If you
would like a reprint of the paper just send me your postal, snail mail, address
and I will ship one out to you until supplies last. After that it's copies!
(You can get the text copy of this paper from the ARTICLES available from
[email protected])
BTW, there are several members of the IPPA who have made exquisite panoramic
cameras on their own. Steve Morton from Australia is one. Jim Lipari is
another. Among the earliest makers of continuous enlargers at the amateur level
are the machines built by Foss and myself. But of course we were preceeded by
the designs that Itek Corporation used to make a continuous enlarger for the US
Air Force in the mid to late 1950's.
BTW, BTW... these cameras are close cousins to peripheral cameras used to
document ancient vases with designs surrounding their periphery. These were
made by the British Museum in the late 1800's. They are also related to
photofinish cameras althogh these were not introduced into use at tracks until
the mid 1930's. DeVeccio (sp) and Western Electric disputed the ownership of
the original idea. But of course the Cirkut camera had them "beat" since it
came about in the late 1800's and was commercially available from Kodak from
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the early 1900's to about 1940 or so.
BTW, BTW, BTW you can expect to see a relationship between these cameras and
something called, in electronic imaging terminology, Linear Arrays. A CCD array
consisting of only one row of pixels. Also related to the word "scanning" that
we have all become so familiar with. Scanning in photo terms was never very
popular but everyone seems to appreciate the word in its "electronic" context.
Interesting! To appreciate what these cameras do next time you are near a
"moving light wand" type copier make yourself a copy of your hand both while
you keep it satitonary and also while you move it along with, against or
sideways as the copy is being made. Scanningly educational activity, this!
regards,
Andy, [email protected]
================================================================================
Note 32.09
-< How to determine the aperture and f# of a lens? >------------------------------------------------------------------------------->Is there any simple way to figure out the *true* aperture of a lens? I know
>that focal length/diameter of front element is an approximation, but how good
>an approximation.
Size of the front element has nothing to do with the aperture (well it does
have some relation to aperture, but no direct relationship). Filter threads are
often standardized by manufacturers to simplify things like filters, lens caps
and probably other manufactured parts used in the construction of the lens.
The aperture is the focal length divided by the diameter of the physical
aperature (as seen from the back so it may be affected by the optics to be
something different from the physical aperture, particularly in something with
a telephoto design). One way of determining the actual aperture is to place a
pinhole at the film plane with a very bright light shining through the pinhole.
With the lens focused at infinity, a card held in front of the lens will
produce a spot on the card the size of the aperture as seen by the film. You
can then sort of measure this spot and calculate the actual aperture from the
focal length and your measurement. If you do try this, be very careful because
the bright light can easily melt or burn something in the back of your camera.
John Sparks, [email protected]
Subject: Is there an easy way to calculate a lens' aperture?
Organization: HP Colorado Springs Division
...............................................................................
Correct me if I'm wrong, but doesn't this assume two things:
1)
2)
That the given focal length of the lens is accurate
That the lens does not over-focus at infinity
In other words, if your 135mm/f2.8 lens is really closer to 133mm, your
measurements will be slightly off. As an example, if your lens were
truly f2.80, then a 135mm focal length should give you a spot that was
48.21mm in diameter (if my math is wrong, someone do the calculations).
If your lens is actually 133mm, then you'll get the same 48.21mm spot,
but your aperture will now be calculated as 2.76.
file:///C|/faq.html (325 of 555) [7/19/2002 3:46:30 AM]
Second, if the lens over-focuses at infinity (most telephoto lenses do,
to accomodate for lens shrinkage/expansion in cold/heat), then two
things happen: First, your focal length decreases, and second, you're
not measuring a true infinity focus.
Small things, but if someone is trying to accurately determine their
aperture with any great precision, these things do need to be taken
into account.
I know how to deal with the second one (focus on the moon. poof!
You're at infinity focus). The first one, I would approach by doing
some painstaking macro work. Take your lens at infinity focus (ha!)
and maximum aperture (again, ha!) with a +4 diopter lens on it. Take a
picture on slide film of something with a known, accurate length (a
good millimeter reference would be nice). Measure the image on the
film to determine magnification ratio. From that, you can calculate
the "true" focal length of the lens to some amount of precision.
Whew.
Too much math for me in one day.
:-)
I'm done.
[email protected]
.............................................................................
ECLDCO,
In other words, I think we are saying the same thing when I say that
_if two lenses are truly f:2.8_ then the aperture of a 135mm lens is
48.2mm and the aperture of a 133mm lens is then 47.5mm.
OTOH, if the effective apertures are the same 48.2mm, then a 135mm lens
will have a f# of 2.8 while another one, which may have a focal length
of only 133mm would have an f# of 2.76
Whether one can accurately measure spot sizes to within 2/10mm accuracy
is something else again. In fact, the procedure of projecting light
backwards through the optical systemdoes depend on accuarcy on the size
of the pinhole at the image plane. Once it gets too large the edges of
the spot start to get too fuzzy to accurately determine the diamter of
the spot.
I think the poster of the previous article was a bit misleading in
refering to the size of the aperture as seen from the rear. This is
true but the f# is determined by dividing the focal length by the
diameter of the "entrance pupil". That is why the method for
determining its diameter by shining a light "backwards" through the
system is appropriate. The spot you will see is an indication of the
size of the front or entrance pupil.
He did mention (I believe) that you would have the lens focused on
infinity. By definition therefore any lenses that are not focused on
infinity first need to be adjusted for that condition. When a complex
zoom or tele lens "over-focuses" as you state it is obviously not
focused at infinity.
file:///C|/faq.html (326 of 555) [7/19/2002 3:46:30 AM]
Since a knowledge of the focal length is important you are absolutely
correct in stating that you must either assume it is correctly marked
on the lens, that is is within acceptable limits or determine it for
yourself.
The best method for determining focal length is through use of a nodal
slide. As for determining the focal length of a lens by focusing on
a nearby object using the +4 diopter lens as the basis for the
calculation that depends also on assumptions that it is indeed a +4 and
not a +4.1 diopter lens or some such variant. In fact, it may be easier
to do this with a +1 lens whose focal legth you can more easily measure
by focusing it on a distant object and measuring from the center of the
glass to the image plane.
Another variation is to accurately measure the size of your image gate
in the camera. Lock shutter open and placing a groundglass in the film
plane then aim the camera at some distant object and line it up so that
the object lies at one edge of the frame. Draw a line on a pice of
paper below the camera body using the base of the camera for a ruler.
Then swivel the camera in the opposite direction so the object now is
coincident with the opposite edge of the gate. Draw another line as
before intersecting the previous line. Remove camera. Bisect the angle
betwee the lines and "move" a line perpendicular to this one and equal
to the size of the image gate in your camera, until it touches the two
lines drawn on the paper. Once this is set up measure from the
intersection of the lines to the line representing your image gate and
that will be the focal length. (to some amount of precision also)
Ultimately, whether an error of 2.8 vs 2.7 or even 2.5 is significant
is a matter that is so dependent on accuracy throughout the system as
to often not being meaningful at all since there are so many errors
that can creep into the photographic process. You just hope that they
don't all add up in a single direction all at once! (This last statement
is more a statement of philosophy than anything else)
cheerio,
andy, [email protected]
...............................................................................
With multi-element telephoto designs this rule of thumb (focal length divided
by diamter of fron element)will tend to give a lower (ie faster) f-number than
the true value, because the front element is enlarged to minimise vignetting.
The figure you really want is the diameter of the entrance pupil which can be
estimated by holding the lens up to the light, with the front element towards
you, and measuring the size of the aperture in the lens as it appears from the
front. This doesn't work well for very short focal- length lenses - see David
Jacobsons lens tutorial for more information, and Rudolf Kingslake "Lens Design
Fundamentals" for lots of details.
Only ray-tracing or very careful experimentation can determine the true f-ratio
at different points in the image. For interest, here's some measurements off a
couple of lenses I have here:
Lens
Front element
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Entrance pupil
35mm, f/2
100mm, f/2.8
26mm (f/1.3)
35mm (f/2.9)
16mm (f/2.2)
32mm (f/3.1)
Christopher
=======================================================
Christopher Hicks
http://www.eng.cam.ac.uk/~cmh
[email protected]
Voice: (+44) 1223 3 32767
=======================================================
............................................................................
The effective aperture is defined as the diameter of the entering beam of
light that will just fill the opening in the diaphragm of a camera lens
or other optical system.
When the focal length of a photographic objective is known, it is only
necessary to determine the diameter of the entrance pupil in order to
find its relative aperture. The diameter of the entrance pupil may easily
be found experimentally by a process devised by A. Steinheil. After the
camera is set on the infinity mark, the ground glass is removed and
replaced by an exactly-fitting piece of cardboard which has a small
circular hole about two millimeters in diameter at its center. Care
should be exercised in fitting the piece of cardboard, since its center
should coincide with the optical axis of the lens. In the darkroom a
small piece of bromide paper is fitted inside the lens cap, and this is
placed over the front of the lens with the emulsion side of the hole
toward the lens. An incandescent lamp is now held behind the hole in the
cardboard for a few seconds. A black circular disk will be found upon the
bromide paper upon development, the diameter of this circle being equal
to the entrance pupil of the objective. The f/number, or speed of the
lens is now readily found by dividing its focal length by the diameter of
the black circle appearing on the bromide paper.
Neblette has a fairly detailed discussion of the elements of lens design.
The fact that this book was written in 1946 is rather clear!
Warren Pearce - [email protected] - Colorado Springs
================================================================================
Note 32.10
-< Pointers for including the moon in a photograph >-------------------------------------------------------------------------------> I need some suggestions in photographing a rising full moon.
<While about 1/125 of a second at f11 is a common suggestion since the moon
is an object in bright sunlight ...> This advice works for a full moon high in
the sky. But when the moon is near the horizon, it may be much dimmer,
depending on the atmospheric conditions in the area. The "Loony 11" rule
(1/(film speed) at f/11) will give the _least_ exposure likely to give a good
full moon. Bracket from there toward longer exposures. For an orange moon on
the horizon, I'd go several stops toward more exposure.
Be careful not to let your exposure time go beyond a second or so if you want
any detail of the moons surface. The moon traverses its own diameter in the sky
every 3 minutes or so. Motion blur will be significant with longer exposures.
Then again, if there's enough stuff in the atmosphere to make the moon orange,
you probably won't see any surface detail anyway. Exposures above 15 seconds or
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so will make the moon look oblong. If foreground isn't an issue, open up your
aperture rather than use longer exposures. Depth of field usually isn't an
issue when your subject is 240,000 miles away.
It takes a longer lens than you'd imagine to make the moon look as large as
you'd expect in the frame. To fill the frame on a 35mm camera, you'd need about
a 2500 mm lens. (Note: There's a popular misconception that a 1000mm lens is
about right to fill the frame with the full moon. It's wrong.) One popular (and
maybe overdone) technique to deal with this (as most of us don't have 2500mm
lenses) is to do a double exposure. Expose the full moon in one part of the
frame with a 300 or 400 mm lens. Then expose some other picture with a shorter
lens on the same frame. It will help if the area occupied by the moon in the
second scene is black sky. This "oversized" moon effect helps compensate for
the tendency for the moon to look too small in normal photographs.
And finally, it's difficult to catch a rising full moon on the horizon and
compose it in a scene. The trick is to predict where it will break the horizon.
Even if you can do that, cloud cover often obstructs the moon until it's a few
degrees up. One pretty good approximate way to predict the point of moonrise is
to note that the full moon will rise almost exactly opposite the point of
sunset. As the sun goes down and shadows get long, the shadows will point to
the approximate point where the moon will rise a few minutes later. The time of
moonrise is about 50 minutes later than the time it rose the night before. Or
you can look in your newspaper. The time of moonrise is often given on the
weather page. Good luck,
Dave Boyd, [email protected],
Hewlett-Packard, Greeley, Colorado
Standard Disclaimers Apply
================================================================================
Note 32.11
-< Sun and Moon rise/set locator program retrievable from Net >-------------------------------------------------------------------------------If you would like to know where (Compas Setting) and when (Time) the sun
or moon will rise or set ftp to:
ftp.funet.fi/pub/astro/prog/win
and download the files
alw113a.exe and alw113b.exe
The planetarium program will tell you the compas location next to
The rise and set dates and times are under Calendar
Azi:
33.01
-< Starting points for using Konica and Kodak Infrared films >-----------------------------------------------------------------------------> I've just bought a Hoya R72 filter, I wonder if someone has worked with this
> filter apparently it cuts the spectrum at 720 nm. 1.- How do you expose Kodak
> HIE and Konica IR with this filter ? 2.- If I use it with IR Ektachrome can
> I obtain something ?? or I will only waste my film.
I can't help you with HIE, other than to say I'd try some test exposures
centered around EI 200, but I can help with the Konica. This film only goes a
little past 750 nm (nanometers, the wavelength of the light). This is
sufficient to record the infrared fluorescence of chlorophyll, which gives the
effect of white foliage in B&W infrared photos.
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As a result, a 720 nm filter, whose cutoff (3dB) point is 720 nm is eliminating
all but the IR light. I use a #23 filter at an EI of 10, a #25 at EI 8. Since
you are filtering even tighter, and since I have no idea how you process, I
would start at EI 10, and make identical test exposures at EI 8, EI 6, and EI
4, also. Then, I'd process the film as described in the instructions, pick the
best negative and go with it. Waste some time and effort on this film, it's
really nice. In order to get every bit of speed the film can give, I normally
process it in dilute microphen (1:3), and the result is good speed, great
sharpness, and unblocked highlights. Forget fine-grain developers, as the
grain is like Pan-F or TMX at worst. I haven't tried it, but Diafine might
give an extra stop or so. It seems to work with everything else!
Regarding, EIR, remember that it is a film which records blue and green as
blue, records yellow-red as greens, and IR as red. If you use your IR, all your
slides will be reds! Far better to use a #12 yellow (minus blue), or failing
that, even a # 8 yellow. This way you'll get all three dye layers to add to the
image. I saw a few slides once shot through a Cokin (I believe) sepia filter
that were wild! Remember that the preconcieved rules went out the window when
you loaded this stuff! My few experiences with it were that I got good
exposures depending on Kodak's exposure recommendations, and using my SRT-101's
meter set to Kodak's recommended EI.
Edward M. Lukacs, LRPS, Miami, FL, USA, [email protected]
...............................................................................
I don't know about the Konica since its response is pretty low beyond about
750 nm. I have used the Kodak HIE and I would suggest the following supposing
the Hoya R72 filter is very similar in spectral transmission characteristis to
the Wratten 88A. The following is from a Kodak data sheet:
Film Speeds - these numbers are guides only - use them as starting points:
Film Speed in ASA rating - assumes development in D-76
Kodak Wratten
Daylight or
Gelatin Filter
Electronic Flash
Tungsten
------------------------------------------------No. 25, 29, 70, 89B
50
125
No. 87, 88A
25
64
No. 87C
10
25
None
80
200
As for your second question, if I use it with IR Ektachrome can I obtain
something ?? or I will only waste my film ... the answer is you will get
something ... red transparencies.
andy, [email protected]
================================================================================
Note 33.02
-< Introduction to Gross Specimen Photography - Tutorial >-------------------------------------------------------------------------------AN INTRODUCTION TO PHOTOGRAPHY IN GENERAL AND GROSS SPECIMEN PHOTOGRAPHY IN PARTICULAR
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A Guide for Residents Who Have Had This Unwelcome Chore Dumped Upon Them
Ed Uthman, MD ([email protected])
Diplomate, American Board of Pathology
At its birth about 1824, photography as practiced by its first devotee, Joseph
Nicephore Niepce, was a messy, all- consuming pursuit that made use of such
substances as bitumen of Judaea, lavender oil, and pewter. Today, chemical,
mechanical, and electronic technology has made photography a neat, transparent,
facile technique which we may easily apply to another messy, all-consuming
pursuit: gross anatomic pathology. Despite the amount of automation available
in photography, it is important to grasp a few general principles, so that we
may use to our advantage a few powerful controls we have over the photographic
environment.
The main considerations in gross photography are exposure, focus, image size,
composition, color balance, and film selection.
I. EXPOSURE
This is essentially the problem of balancing the amount of light coming through
the lens with the sensitivity of the film. We seek the ideal exposure and
eschew the underexposure (slide too dark) or overexposure (slide too light).
The determinants of exposure are:
A. FILM SPEED, measured as arbitrary standardized units ("ISO" or, formerly,
"ASA"). ISO and ASA are numerically equivalent units. The film speed depends on
film manufacturing process and type of development used on the exposed film.
Although films are packaged with a stated ISO rating, some may be "pushed" to
higher speeds by special processing techniques. This should be kept in mind
before throwing away valuable film you have mistakenly underexposed. The faster
the film, the less the resolution (causing increased "graininess"); also colors
are more subdued in fast film (such as Kodacolor 1000) than in "slow" film
(such as Kodacolor 25). The graininess and subdued colors of very fast films
can be used for artistic effect but are of no value in technical photography.
Therefore, we tend to choose slower films for our gross lab cameras, so that we
may produce pictures with the greatest resolution and most accurate color
rendition. A film faster than ISO 160 should probably not be used.
B. APERTURE, the setting of the iris diaphragm in the lens, determining how
much light is allowed through the lens into the camera. Aperture measured as
"f/ stops" (f/2.8, f/4, f/16, etc). The f/ ratio is calculated by dividing the
focal length of the lens (see below) by the diameter of the iris diaphragm
opening through which light passes. Therefore, the greater the diameter, the
more light is let in, and the smaller is the f/ ratio. Each f/ stop is 1.4 (the
square root of 2) times the preceding f/ stop. Each "stop" multiplies the
amount of light by 2X. As an example, f/1 lets in twice as much light as f/1.4
and four times as much as f/2. The "speed" of the lens is its f/ ratio at its
widest aperture setting. An f/1.2 lens is considered very "fast," while an
f/5.6 lens is "slow." Generally, fast lenses are more expensive than slow ones
and in fact do not have as good corner-to-corner resolution as slower lenses.
Because we generally have plenty of light at our disposal in gross photography,
we opt for excellent resolution over lens speed. Most lenses for our purposes
are f/2.8 to f/4 at their widest aperture settings. We typically choose to
"stop down" our diaphragms in most cases, because almost all lenses have
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optimal resolution when not used at their maximum aperture. The "ideal" f/ stop
is generally taken as 2 to 2-1/2 stops "down" from the maximum aperture. For an
f/2.8 lens, therefore, the optimal aperture setting would between f/5.6 and
f/6.7. The other reason to stop down from maximum aperture is to improve "depth
of field" (see "Focus," below). I personally shoot almost all my specimen
photos at f/8.
C. EXPOSURE TIME, or "shutter speed," measured in seconds or fractions of
seconds (1/30 s, 1/1000 s, etc) represents the total time the film is exposed
to the focused image. It is determined by setting the camera shutter to open
for a specified length of time.
Effects of various shutter speeds:
1/1000 sec - 1/60 sec: These are OK for hand held camera in existing light.
1/60 sec : Always use this with electronic flash, since just about all flashes
are specifically synchronized for this speed. Using a slower speed (e.g., 1/30
sec) will also work, but a faster speed (e.g., 1/125 sec) will ruin the picture
by failing to expose part of the frame. Note: Some of the more modern and/or
expensive cameras allow flash synching at 1/125 second or faster speeds, but
make sure this is true of your camera before trying it.
1/30 sec - 1/2 sec : We tend to use this range for tripod or copy-stand work,
including gross photography. This range is generally not acceptable for
hand-held cameras, because most people cannot hold the camera still enough for
this length of time. By using these slower speeds for gross photography, we
allow ourselves the luxury of smaller apertures (giving us good depth of field
and maximum resolution from the lens) and slower films (giving us maximum film
resolution and best color rendition).
For example, each of the following exposure parameter set- ups give the same
exposure. Which would you choose for a gross photograph taken on your copy
stand, assuming you have a camera with an f/4 lens?
A. ASA 50 film; f/4; 1/30 sec
B. ASA 50 film; f/8; 1/8 sec
C. ASA 200 film; f/16; 1/8 sec
I would choose set-up 'B.' Set-up 'A' involves shooting at maximum lens
aperture, at which lens resolution is not the best. Set-up 'C' lets us stop
down the aperture for good lens resolution but requires us to use faster film
with poorer resolution than the ASA 50. Therefore, 'B' looks like the best
compromise.
Even though a good copy stand will keep the camera motionless and allow long
exposure times, there is a theoretical problem, called "reciprocity failure,"
which may interfere with color balance in very long exposures. But this is
never a problem as long as you don't allow the exposure time to exceed 1/2
second, and you'd probably not notice it even if you shot a 2-second exposure
(which may occasionally be necessary when using bellows at maximum extension;
see below).
How do you determine exposure? There are two ways to do this:
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1. Most cameras have a built-in light meter that monitors the amount of light
coming through the lens. This meter attempts to optimize the exposure either by
averaging the total light hitting the film plane (an "averaging meter") or
using a small sample area (usually the center of the field) to measure the
amount of light focused on that particular spot (a "spot meter"). In an
"aperture priority" system, the meter then looks at the aperture you have set
on the lens and automatically adjusts the shutter speed to give the desired
exposure. In an "shutter priority" system, you set the shutter speed and the
light meter automatically adjusts the aperture. These functions are available
in what is referred to generally as the "auto" mode. In addition, most modern
cameras have a "program" mode, which completely automates exposure
determination by choosing both the aperture and the shutter speed for you. This
means all you have to do is compose the picture, focus, and push the button.
Program mode has been a boon for photography in general, because it allows you
to concentrate on composition and not have to worry about fiddling with
aperture rings and shutter speed knobs. There is, however, a price to pay,
especially in technical photography. The main problem is that automatic
exposure systems (except in high-end cameras) are standardized for snapshot
type photography, where there is no striking difference between background and
subject illumination. Also, an automatic exposure system will attempt to make
the subject have a "neutral" brightness. In technical photography, we do not
necessarily want this; we want brain to look light and spleen to look dark,
just like these respective subjects appear to us in real-time. Therefore, I do
not use the camera's automatic exposure system for routine specimen
photography.
2. Because of the above considerations, I recommend that you take advantage of
the rigidly standardized exposure environment of the copy stand and virtually
always use manual exposures. Determine the ideal exposure by shooting a roll of
film at various settings and then stick with this exposure when shooting
specimens. You can still use the light meter when faced with an unstandardized
situation, such as having one of your four floodlights burn out on Saturday and
not being able to find a replacement.
Parenthetically, I have found through experience that when shooting documents
of black printing on white paper, you should use an exposure one stop brighter
than your standard setting for specimens. For instance, if you normally shoot
specimens at f/8 and 1/8 sec, you should choose f/8 and 1/4 sec when shooting a
document. Never, never let the camera shoot black-on-white printed documents on
"Auto" or "Program," because the camera will think you want the white paper to
appear neutral and will force a bad underexposure.
Another hint: When forced with shooting pictures on a set-up you are unfamiliar
with, you may have no idea what settings to use. A good solution is to meter on
the palm of your hand (believe it or not, it makes no difference what color you
are; the palm of everyone's hand looks about the same to a light meter) and
note what settings the camera's light meter indicates. Simply switch over to
manual and enter these settings. Then you can shoot away and always get at
least acceptable results.
II. FOCUS
There are two things to consider here, methods of focusing and depth of focus.
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A. Methods of focusing.
1. Autofocus. Most manufacturers today produce autofocus cameras aimed at
various markets. The most popular of these, aimed at the advanced amateur and
the professional, are probably the Minolta Maxxum series and the Canon EOS.
These cameras are packed with automation which allow automatic film advance and
rewind, automatic and program exposure modes, and autofocus. Automatic focusing
uses a system whereby a computer in the camera uses vertical lines in the
subject and focuses the lens by analyzing these lines. I have not used
autofocus systems in specimen photography but have experience with them for
snap shooting. The problem is that if there are insufficient vertical lines in
the picture, the focusing system with be fooled and can leave you with a
terribly out-of- focus picture. I have stuck with manual focusing for specimen
photography but would love to hear what the autofocus aficionados have to say
about its use.
2. Manual focus. In this method you simply view the subject through the
viewfinder and turn a focusing ring until the subject sharpens. If you have a
choice, I recommend a viewfinder with a split-field focusing prism to help with
critical focusing, but others prefer a focusing grid, which, as far as I know,
is only available on high-end cameras, like the Nikon F series.
B. Depth of field
It is easy to focus on a flat object, such as a slice of brain, but things get
stickier when photographing objects with depth, such as a windowed pediatric
heart specimen. Shooting these subjects requires a knowledge of the concept of
depth of field. It turns out that the zone of depth at which the camera is in
focus is greater at smaller apertures (larger f/ numbers) than at larger
apertures. Therefore focusing is very critical when the lens is "wide open" but
much less so when "stopped down." Let's say you are shooting an opened colon to
demonstrate, en face, a large villous adenoma. If you focused on the "top" of
the tumor (the part nearest the camera) and shot the picture with the lens
aperture at f/2, the tip of the adenoma would be in focus, but the sides would
be slightly out of focus, and the surrounding colonic mucosa would be totally
out of focus and probably not recognizable. However, if you stop down to f/16,
the entire specimen would be in focus. Since this results in decreasing the
exposure by six stops, you would have to compensate by increasing the exposure
time by a factor of two to the sixth power, or 64. For good depth of field and
optimal lens resolution, I use f/8 routinely and reserve f/16 and f/22 for
subjects like the windowed heart. Most cameras have a "depth-of-field preview
button" that lets you stop down the lens to its preset aperture, so you can
view how much depth-of-field you'll end up with in the resulting picture
(normally the aperture diaphragm stays wide open until the instant the picture
is taken, so you have a nice, bright viewfinder in which to compose the shot).
III. IMAGE SIZE
The size of the image in the camera depends on 1) the size of the subject (of
course), 2) the distance of the subject from the camera, and 3) the focal
length of the lens. The focal length is the distance from the lens to the image
when the lens is focused on infinity. The effects of lens focal length are as
follows:
The greater the focal length,
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1. The larger the image appears for a given distance.
2. The farther away from the subject you can be for a
given image size.
3. The more critical the damping of camera motion to
prevent blurring.
4. The slower and more expensive the lens.
5. The less the sense of depth and perspective.
6. The less the curvilinear distortion of straight lines.
7. The _more_ flattering to the face in portrait
photography (makes face less moony and nose less
prominent).
8. The _less_ flattering to the body in figure
photography (makes subject look stouter).
Lenses are classified in groups based on their focal lengths and other
properties:
16 - 35 MM (WIDE-ANGLE LENSES). Rarely used in medical photography, these are
best for landscape and architectural photography. They make landscapes look
more expansive and buildings more imposing. They tend to be extremely sharp
lenses that have excellent contrast.
50 - 58 MM ("NORMAL" LENSES). These are used for most routine work, including
gross photography. It is rarely necessary to use anything other than a normal
lens for our purposes except when shooting close-ups so extreme that the bulk
of the lens shadows the subject, so that it cannot be illuminated sufficiently.
In this case you need:
80 - 135 MM (MEDIUM TELEPHOTO LENSES).These are used for high-magnification
macrophotography to increase working distance, and for "over the shoulder"
intraoperative photography. For instance, you can be twice as far away from the
subject with a 100 mm focal length telephoto than with a 50 mm normal lens and
still get the same image size on film.
200 - 2000 MM (LONG TELEPHOTO LENSES). These are usually not used in medical
photography but are indispensable in sports, nature, and journalistic
photography.
MACRO LENSES. Operationally, the only thing special about these is that they
have an extra long focusing extension to allow you to focus on very close
objects. They are generally available in the "normal" focal length and the
medium telephoto ranges. For instance, Nikon makes two excellent macros, a 55
mm and a 105 mm. Since they are aimed at the technical market, macro lenses
tend to have excellent optics, are very durable, and are several times more
expensive than normal lenses of corresponding focal lengths. Most macros in the
normal lens category allow you to focus down to objects close enough to give
you a "3:1" or "2:1" ratio; that is, the image size is one- third or one-half,
respectively, the size of the subject. Most macro lenses can be used with an
inexpensive extension ring, which allows focusing down to 1:1 or "life size,"
i.e., the image size is the same as the subject size (Sigma makes a very nice,
not-too-expensive macro lens that focuses down to 1:1 without an extension
ring). This allows you to take some breathtaking shots of otherwise
unimpressive subjects, such as pituitary adenomas. You can even make a corpus
luteum look spectacular.
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VARIABLE FOCAL LENGTH (ZOOM LENSES). These are very convenient for general
photography, since you don't have to move the camera so much. I am still
waiting for someone to come up with an affordable zoom lens that is macro at
all focal lengths and can focus on close objects. Many of the lenses advertised
as "macro-zooms" are really just zoom lenses that allow close-up photography
only at a fixed focal length. When in "zoom" mode, such lenses are not macro.
Other zooms supposedly have "continuous close focusing" throughout their range
of focal length, but the specs I have seen on these show that they all have a
minimal focusing distance that is too long for practical use on a copy stand.
My advice is too stay away from zooms unless you are really up on the
capabilities of the individual models and know exactly what you need.
BELLOWS. This is not a lens at all but simply a shade that extends the lens
very far away from the body of the camera. This allows you to take true
photomacrographs, producing an image size up to three times that of the
subject. For instance, when shooting a 105 mm lens on a bellows at full
extension, the Lincoln Memorial on the reverse side of a U.S. penny fills a
35mm frame. Multiply this magnification by the amount you get when projecting a
slide in a lecture hall and you get some idea of how Brobdingnagian a world you
can present to an awed audience. The only problem with the bellows is that
light intensity fall-off (as per the inverse square law) at maximum extension
requires you increase the exposure accordingly. Also you have to be extremely
careful about camera motion, which is magnified correspondingly.
IV. COMPOSITION
If you consider yourself more of a technical type than an artiste, you are
probably intimidated by this aspect of photography. Although Ernst Haases and
Edward Steichens are probably born and not made, much technique of composition
can be easily learned by the average eye. In gross photography, first step is
good specimen preparation. This is what separates the excellent from the
mediocre; the inspired pathologist from the drudge; art from mere visual
documentation. After you get comfortable with the camera, you should spend
almost all your time preparing the specimen, with the actual photography being
a brief anticlimax. Here are some tips I find useful:
A. Cut away tissue that is of no interest, or that obscures the interesting
features.
B. Use props to position the specimen when necessary. A slice of liver needs no
props, but a gallbladder looks better when you shove a few wads of paper under
the periphery to make it look like the saccular structure that it is. Modeling
clay is also a good material from which to devise custom props.
C. Watch out for the obtrusive ruler. A lot of pathologists remonstrate
incredulously when I tell them I almost never shoot a specimen with a ruler in
the field. For one thing, no one has made a ruler yet that is as unobtrusive as
I would like. Most specimens need no ruler, especially full organs or full
organ slices. We all know how big a lung is; if not, we're only there for the
free lunch anyway. If you really want to know how big the lesion was, just read
the gross; it even gives all three dimensions! If you really want to impress
the conference attendees with how big a goiter is, take a picture of it with an
everyday object, such as set of keys. Or, better yet, bring the gross specimen
to the conference and ceremoniously drop it on the table with a loud thud.
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I quit using rulers when I realized I never looked at them except to marvel at
how distracting they were. I really don't think any one else looks at them
either. But if you're so anal that I can never convince you to lose the ruler,
do me a favor and shoot just one of your frames on each specimen without it.
I'll guarantee you that nine times out of ten, that's the pic that you're going
to want to show at the conference.
D. Keep the background clean. This is a real pain, but to do otherwise really
compromises the photograph. It is much easier to keep things clean when dealing
with a fixed specimen than a fresh, bloody one. On a related note, try to keep
the camera clean. Layers of dried gore accumulating on the body of a tough
Nikon F3 probably won't hurt the camera, but it tends to gross out certain
people, particularly OSHA inspectors.
E. When photographing lungs or hollow viscera, use inflation- fixed specimens
when possible. You have to resist all sorts of pressure from various circles to
cut up the specimen when it is in the fresh state, but, then again, all great
artists suffer for their work. I have yet to see a gross photograph of
uninflated, unfixed lung that was any good. Inflation fixation of gut segments
delays your diagnosis a day but rewards you with gross photographs that would
bring tears to the eyes of any radiologist.
F. Try to get rid of as much blood as possible. Otherwise, the specimen ends up
being just varying shades of red and pink.
G. Watch out for distracting highlights. Fresh specimens usually have very
shiny surfaces that produce glare. There are several things you can do to cut
the glare on a fresh specimen:
1. Formalin dip for just a few minutes; this preserves color but dulls the
surface; in overnight-fixed specimens which have lost their color, soak in 70%
EtOH to partially recover color.
2. Turn off room lights.
3. Consider changing the lighting situation of your set- up. Nice copy stands
are usually set up with four big floodlights. You may consider turning off the
two on the front of the stand and leave the two on the rear on. Remember to
adjust your exposure to accomodate the loss of these lights.
4. Polarizer/analyzer filters do a great job, but the big polarizers that go
between the floodlights and the subject are very expensive and fade out fairly
rapidly.
H. Photographic backdrops. The choice of a proper backdrop is essential for a
professional looking photograph. The best background is the one no one knows is
there. Several options are available:
1. Transilluminated light board with non-glare glass - expensive; klutzes drop
things on the glass and break it; departmental business manager is incredulous
at expense of replacement and usually stalls its purchase.
2. Wet black velvet - less expensive ($12/yard); reusable for a long time if
you're careful; keep fresh, bloody tissue off! Give each resident his/her own
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piece. Of course, if you shoot anything that may have infectious agents on it,
you can't re-use the velvet, unless yuo can find a way to sterilize it (another
argument in favor of shooting only fixed tissue).
3. Water immersion tray - Incredible shots of delicate, "three-dimensional"
objects make you into an amateur Lennart Nilsson; solves problems of gravity
and glare simultaneously for such objects as villous adenomas, chorionic villi,
emphysematous lungs, etc. In my experience, it takes quite a bit of patience to
get a good shot, as undesirable bits of grunge tend to float into the field of
view just as you are releasing the shutter.
4. Towel from surgery - sure sign of an amateur; an embarrassment to say the
least. However, if that's all you've got, ask for a clean towel to replace the
bloody one they handed you the specimen on.
V. COLOR BALANCE
We perceive a sheet of paper illuminated by an incandescent bulb to be just as
white as if it were illuminated by direct sunlight. This goes along with our
concept that "white" light is composed of light of all colors. This is true to
an extent, but various "white" light sources produce their component colors in
varying proportions. For instance, the surface of the sun has a temperature of
about 6000 Kelvins and has much more blue light in it than the radiating
surface of a tungsten filament glowing at 3200 Kelvins, which has more red
light. This relation between temperature of a glowing object and its color is
well known to most people (although not by its scientific name - Wien's First
Law), since we are taught from the fifth grade that a blue flame is hotter than
a red one.
Although the neurological visual processing system behind our eyes compensates
for this variability, the film in a camera cannot. The solution is to make film
where sensitivity to the colors of the spectrum is specifically balanced for
the color distribution of the light source. When shooting in daylight or with
an electronic flash, we need to use "daylight" film. Alternatively, when using
incandescent lights (such as the floods on the copy stand), we need to use
"tungsten" film. This is not some theoretical consideration. If you try to use
daylight film with the floodlights you will get an unacceptably orange picture;
conversely, shooting tungsten film with a flash will produce a picture that
looks like it was painted by Picasso during his "blue" period.
VI. FILM SELECTION
You will select film based on your need for good resolution, your budget, the
necessity of rapid processing turnaround time, and the format in which your
photographic work is to be presented.
A. Color transparency film. These yield the 2" x 2" mounted transparencies
known affectionately as "kodachromes" (in the way that facial tissue is known
as "kleenex"). The actual frame size of the transparency is 24 x 36 mm.
1. E-6 process color reversal film (Ektachrome, Fujichrome). Compared with
Kodachrome (see below), these are expensive; they have quirky color response
(being notoriously poor in rendition of eosinophil granules, which look kind of
dull purple rather than vivid orange), and the slides fade with time (although
this may not be true of newer films in this category). Nevertheless, the E-6
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films are by far the most popular in med center settings because of the ready
availability of the E-6 process. Most professionally oriented processors can
routinely turn around the film in four hours. With a readily-available kit, you
can even process these films at home for about US$3 per 24- exposure roll (plus
a one-time US$30 investment for a developing tank and reel).
2. Dye injection film (Kodachrome). Kodachrome is superior in every way to the
E-6 films, except that the processing is slow and is usually done in large
reference centers where the film must be sent. Eosinophils look great, and the
slides last essentially forever if stored properly. It is difficult to find
tungsten versions of Kodachrome, but the daylight versions can be shot under
tungsten illumination if a special filter is used.
B. Color negative film (Kodacolor, Ektar). Also generally available only in
daylight versions, these films yield color negatives which must be printed. It
is preferable to use color negative film for posters, rather than having color
prints made from your transparencies. This is because color prints from
transparencies usually suffer from enhanced contrast that compromises the
accuracy of the rendition. When having color prints processed, you must work
closely with a skilled print processor for good, publication-quality prints.
The automated printing machines used in "one-hour" facilities are not capable
of producing an accurate print from a color negative of scientific subject
(unless, perhaps, it is a portrait of the scientist).
C. Polachrome film. This abomination of a transparency film develops in a few
minutes in a processor you can keep in your desk drawer. It is extremely
expensive, and the dense emulsion makes slides too dark on projection; the
colors are less than impressive. It is best not to let the clinicians know you
have a Polachrome processor. They will start giving you the conference cases
even later and will not realize how lousy the pictures are, while you are
grinding your teeth trying to find that audience- pleasing mitosis somewhere on
the screen.
D. Black-and-white film. Not to go into this at any length, but you should use
this for originals to be used for publication. Black-and-whites made from color
negatives or transparencies are generally second-rate. Also you can experiment
with color contrast filters, which can really improve results.
ACKNOWLEDGEMENTS
Dr. Donald McGavin, Professor of Pathobiology, Univ. of Tennessee College of
Veterinary Medicine, generously provided many fine suggestions from detailed
review of the first version of this paper, and I have incorporated most of them
into the current version. However, the opinions given here are ultimately mine,
as are any errors. I also wish to posthumously thank my father, G. O. Uthman,
who taught me, among many other things, the basics of photography.
IMPORTANT
Please send any constructive comments about this paper to Ed Uthman,
([email protected]). I am especially interested in correcting any
errors that may have crept in.
COPYRIGHT NOTICE
file:///C|/faq.html (339 of 555) [7/19/2002 3:46:30 AM]
Copyright (c) 1995, Edward O. Uthman. This document may be freely distributed.
It may be reformatted for purposes of compatibility. It may be freely used for
personal and educational purposes, but it may not be used for commercial
purposes without prior written consent of the author. It may be included in
toto or in part as components of other documents with proper attribution.
DISCLAIMER
While I have made every reasonable attempt to include only accurate
information, it is very likely that some of the information is wrong.
Therefore, I am not responsible for anyone's screwing up their pictures because
of a naive belief in everything said here.
Version 2.00, June 30, 1995
>With all those new zooms that don't have depth of field scales, I'm
looking for some help on depth of field. On the lenses that I've used and
looked closely at, it seems that the IR setting on lenses is the same as f8
setting on the depth of field scale. Is this true in general for all lenses?
Since some Canon zooms don't have DOF scales but do have the IR indices at
various focal lengths, IR = f8 is better than nothing.
You can't assume that the IR mark and the f/8 mark are at the same place for
all lenses. I have several lenses in which the IR mark is not near the f/8
mark. The position of the IR mark is going to depend on the design of the
lens, the type of glass used, and so on.
The best way to do what you want is to calculate where the DOF marks should go,
using the formula for hyperfocal distance.
h = f^2 / Nc
h is hyperfocal distance, f is focal length, N is f-stop, c is circle of
confusion (most manufacturers use c=0.03mm for 35mm equipment). When the lens
is focused at h, the two DOF marks are at h/2 and infinity on the distance
scale. For example, for a 50mm lens at f/8, h is 10.4 meters.
[Note, of only theoretical interest: nominally there is a relation between
focal length, DOF mark, and IR mark. Kodak says, if you have no IR mark, try
extending the lens 1/400 of focal length. It's possible to show that this
means the IR-mark should go at the DOF-mark for f-stop N = f/401c, where c is
whatever circle of confusion was used to calculate the DOF scale. If c=.03mm
as is usually true for 35mm, the IR-mark goes at N = f/12. So a 50mm lens
would have an IR-mark around f/4, a 100 mm lens would have it around f/8, etc.
I looked at a few lenses and this seemed to work OK for non-exotic prime
lenses, but didn't work too well for the two zooms I own. Which means the
Kodak recommendation isn't likely to work for zooms - makes sense given their
more complicated design.]
From: [email protected] (Ben Weiner)
Organization: Rutgers University
>In a recent messsage [email protected] mentions divided development with
>D23 to get long scale negatives (ie with 14 tone steps). In the ancient past I
>used D23 with Plus X, and it did indeed produce a very long scale negative. I
>have two questions that I hope someone out there can answer: 1. Does anyone
>have a time/temperature for developing Tmax 100 and/or Tmax 400 in D23?
file:///C|/faq.html (340 of 555) [7/19/2002 3:46:30 AM]
>2. What is divided development, and how is it used with D23?
Split the D-23 as follows:
Bath A start with 750ml water
7.5 g Metol
Sodium sulphite (sulfite) 80g
Sodium Bisulphite 20g
Cold water to make 1 litre
Bath B start with 750ml water
15g Kodalk (balanced alkali)
Water to make 1 litre
I develop in bath A for for 4 mins and bath B for 4 mins (FP4+ sheet). Minimal
agitation in bath B. Experiment, I use Cold Cathode. If you don't see any
postings about Tmax post me.
Loads of references to this in Ansel Adams 'The Negative'. Old Photobooks and
of course that marvellous book that should be on eveyones shelf The Darkroom
Cookbook by Steve Anchel.
Graeme, [email protected] (Graeme Webb)
Path: isc-newsserver.isc.rit.edu!vaxb.isc.rit.edu!ANDPPH
From: [email protected]
Newsgroups: rec.photo.advanced,rec.photo.darkroom,rec.photo.help,rec.photo.misc
Subject: Re: HELP: Lenticular Photography (XOGRAPHY)
Date: 10 Aug 1995 03:12:43 GMT
Organization: Rochester Institute of Technology
Lines: 38
Message-ID: <[email protected]>
References: <[email protected]>
Reply-To: [email protected]
Xref: isc-newsserver.isc.rit.edu rec.photo.advanced:23232 rec.photo.darkroom:798
9 rec.photo.help:17223 rec.photo.misc:22221
In article <[email protected]>, [email protected] (Eric Rayboy) writes:
>Does anyone have info on lenticular photography (sometimes called xography)?
>This is the process of making 3D pictures using a plastic lens over the
>finished product (like the NIMSLO of a few years back). I am seeking books or
>articles on how it is accomplished.
Essentially you take two pictures and slice them up into narrow vertical
strips. Then you discard every other strip of each of the pictures. Then
you place the stips of one in between the strips of the other, in order.
Then you overlay a lenticular screen of the correct design such that at a
given distance your left eye "sees" only one set of strips and the other
sees the other set of strips. If the pictures are a stereo pair you see an
image exhibiting depth.
Instead of a lenticular screen you can also use a "barrier strip", made up
of alternating dark and clear strips. The frequency of these is related to
the frequency of the picture strips, the distance from the barrier strips
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to the picture elements and the viewing distance (and the eye separation of
the viewer!).
The placement of the image strips behind a lenticular (or barrier) strip
can also be done optically as was done by Nishika Labs for Nimslo-format
prints made up of 4 (!) separate images per scene, and as is still done by
Image-Tech for the three-view stereo images. Kodak also markets a system
called Depth Imaging which uses a significantly more coarse lenticular
screen than Image Tech or Nishika do (did) but where the individual images
behind each strip are computer manipulated for enhanced separation and/or
depth resolution.
this is _roughly_ correct i hope ...
andy
o o 0 0 o
o Andrew Davidhazy, at RIT's Imaging and Photo Tech Dept
\/\/\/\/\/\/
[email protected]
High Speed Photography Lab
________|
|__________________________________________________________
>I am going to photograph some lasers, and I was wondering if any one has done
>this before and how long should I leave the shutter open in darkness. Also I
>was thinking of dropping dryice smoke stuff over the laser's beam so that it
>shows up on film, or should I use smoke of some sort?
Depends-- you might just consider that you are going to "blow-out" the laser
line, give it 1-2 sec. at an aperture which will give you the DOF you need. I
have done it this way. But, if the truth comes out, I also pulled a Paranoid to
check the exposure.
I have used a Rosco smoke machine, cuz I have one sitting in the closet, but
when that was inconvenient, I have used Diffuse-It Cloud Spray. It should be
available at any reasonably well stocked pro camera supply. Calumet P/N is
DT5000. Costs less than $10 and much easier to use than dry ice. Also consider
other aerosol sprays. I have tried hairspray, flour, water in a mister, etc.
OBTW, you might want to consider exposing the laser(s) separately from the
subject. Old tabletop guy's trick.
Jim Hartmann, [email protected]
================================================================================
Since the beam itself is invisible you need something in the air to make it
show up. If there are enough particles in the air sometimes a long exposure is
enough. Depending on the air cleanliness.
I often have to photograph in laser labs to show the people and the work they
are doing and want the laser in the image as well. I set up the flash units to
light the scene however I want but try to hit a fstop around f8 ( I use ISO
100 film). I set the camera to the bulb setting and in total darkness expose
by firing the camera and flash and holding for an exposure time of 10 - 12
seconds on average.The flash exposes the scene and the time exposure allows
the laser to image as well as that glow they often give off. Season to taste
with longer and shorter exposures. Often the beam is visible in the photos.
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If the beam is my primary goal I appraoch it slightly differently. I have used
smoke ( I only smoke for my art you understand ), dry ice and an aerosol
called "Diffusion - cloud in a can". This stuff was ungodly expensive and
environmentally hostile but hung in the air for quite a while. No longer
available in Canada so I have no soul searching to do regarding using it.
This diffusion spray and cigarette smoke may not make you popular. If this
laser is on a large bench setup these materials may deposit a film on mirrors
and photodiodes that can be tedious/difficult to clean. Try this:
Set up the camera and set it to bulb. Paint the beam with the dry ice fog as
even as you can for as long as it takes or my favourite way - use a white card
or the card researchers use to detect beams and paint the beam with it. Lock
the camera on time exposure and hold a white card angled slightly to the lens
in the beam so the laser images as a bright dot. Now just move it along the
beam. In total darkness the exposure is however long it takes to paint the
beam. It looks like a rod of light or if a pulse laser it can even be a beam
of dots it you time it right. You can paint all sections of the beam and have
someone else help you at the same time. Usually with ISO 100 at f8 and Polaroid
Best look and make sure to leave no residue or film on the laser equipment!
Harry Turner National Research Council Canada [email protected]
==============================================================================
33.03
-< UK Company that makes microscope (and other?) adapers >----------------------------------------------------------------------------->I am looking for a pentax k-mount microscope adapter that with a 31mm barrel.
>Does anyone know of any vendors that might have such an animal.
There is a company in the UK who will make any microscope adaptor They are reliable, and charge about £40. Takes a couple of months.
Ian R Broomhead
SRB Film Service
286 Leagreave Road
Luton
Beds LU3 1RB
England
John, [email protected] (John Marriage)
==============================================================================
33.04
-< Improvised Contrast Control filters from Rosco materials >----------------------------------------------------------------------------->Our Besseler 23C-II's take the large filters, and we do not want to use
>filters below the lens; however, we only use 3,4, and 5 filters and can't
>afford to buy whole sets just to get them. Does anyone have a source for
>filter material, perhaps sheets we can cut down?
In the Jan 1993 issue of ViewCamera, Joseph Englander suggested the following
Rosco filters to form a useful variable contrast series for larger formats.
The filters probably will not give equal or 2x exposure times for an average
zone 5 density. For consistency, the filter factors should be worked out by
determining minimum times to dmax for each filter and each paper. Most of the
filters sold specifically for variable contrast papers have neutral density
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built in to equalize exposures which isn't the case with lighting or color
correction/conversion filters. From low to high contrast:
3107 Tough Yellow Y-1
389 Chroma Green
3304 Tough Plusgreen 30G
3315 Tough Half Plusgreen 15G
<no filter - G2 would fall here>
3313 Tough Half Minusgreen 15M
3308 Tough Minusgreen (Magenta) 30M or Roscolux 37 30M
3202 Full Blue (Tough Blue) 80A
68
Sky Blue
Rosco: 36 Bush Ave., Port Chester, NY or 1135 N. Highland Ave., Hollywood, CA.
From: [email protected] (Michael Gudzinowicz)
==============================================================================
33.05
-< Reducing overexposed IR film and others too >----------------------------------------------------------------------------->re: reducing what appears overexposed IR films ...don't if you don't have to!
This is very good advice, especially the first sentence! However, if you need
to reduce (more), I would not keep the film on the reel. Two reasons: 1>
Reduction is a gradual processs, but it speeds up exponentially. You need to
be able to see what it is doing and be able to stop it fast!!
2> It may be
that not all the negs on the roll need reduction, and this kind of shotgun
approach (reducing film on a reel) could reduce negs which don't need it, and
once that is done, IT'S DONE!
Here is what has worked for me: Develop, fix, wash, and dry your infra red
film as normal. Go ahead and cut & sleeve it if you like. Note that infra red
film often appears very overexposed compared to standard pan film, but will
print o.k. Try to make a small enlargement before you do any reducing. If it
still is too dense, use this formula:
STOCK SOLUTION A,
Potassium ferricyanide, anhydrous
Water to make
2 tablespoons + 1 teaspoon
16 ounces
Stock SOLUTION B
Normal dilution of non-hardening fixer
2 quarts
Store each solution seperately. They keep for months, but should be used right
after mixing. FOR USE: Mix 30 milliliters of solution A with 120 milliliters
of solution B and add water to make 1 liter of working solution.
Pour the solution in a white tray under a good light source. Drop in the negs
to reduce and agitate for 30 seconds. Pull out the neg and rinse with water,
hold it up to a light and check the density. Go in the solution again if it
needs it, but check it as much as possible to avoid over reducing, which is
uncorrectable. Fix it, wash it, and dry it as usual.
Russ Rosener, [email protected]
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==============================================================================
33.06
-< Tips for photographing the sun >----------------------------------------------------------------------------->Can anyone recomend filters for shooting the sun? I'll be using a 500mm
>mirror lens with an option for 2X converter as well.
A Kodak Wratten Neutral Density filter ND4. Use 1/500 second at F11-F16 with
100 ASA film. An ND4 filter is not the same as 4x. ND4 is 10 to the power of
4, ie. 10000 times intensity reduction. This is the cheapest way to get a good
optical image.
Alternatively at sunset when the sun is touching the horizon, 1/1000 at f22
with no filter works well. The atmosphere does the filtering.
Safety Note: The filter goes between the sun and the lens not between the lens
and the camera. The filter lets through levels of UV and IR which can damage
your eyes. That said, I've been using mine for 15 years. Just focus and frame
without wasting time. If you spend lots of time looking through it then you may
sustain eye damage. A No 14 welders filter is a safe visual filter. These cost
$2. You can safely focus and view through one of these then switch to the ND
filter. The welders filter is unsuitable for photographic use.
Joseph A. Cali, Research School of Earth, email [email protected]
Australian National University, Canberra 0200 Australia
note: the size
equal to 1/100
lens will make
or enlargment.
[email protected]
of the image of the sun's disc at the film plane is roughly
of the focal length of the lens used on the camera. A 500 mm
an image that is about 1/5th the short dimension of the film
(24mm divided by 5mm = about 1/5) this was added here by andy,
==============================================================================
33.07
-< Stage Photography Recommendations >----------------------------------------------------------------------------->I'm going to be shooting a stage production in the near future on 400 speed
>film. I would be pleased to get any suggestions or hints y'all might have.
I assume you're talking about shooting color negative film, since you mention
ISO 400 and are concerned about color rendition? (If you were shooting slide
film, selection would be easy since there are only two choice: Kodak Ektachrome
320T -- nice image quality but slowish -- or Scotch 640T -- grainier, more
muted colors, but a stop faster.)
For print films -- especially with the fairly slow lenses you plan to use -- I
wouldn't even bother with 400-speed films; I'd go straight to Fuji Super G 800.
This film has very nice grain and color rendition. Still more important is that
it has moderate contrast -- this is important in stage photography, since the
lighting is usually quite contrasty. (For example, although I like Kodak's Gold
1000 and Ektapress 1600 films, they're both contrastier than the Fuji film and
can get hard to manage under theater lights.)
Your biggest problem with color rendition is going to be that stage lights are
tungsten, but all 35mm color neg films are daylight balanced. That means your
pictures will have an inherent yellow-orange cast. The lab that prints the
negatives can correct this for you, but may have trouble knowing how much
file:///C|/faq.html (345 of 555) [7/19/2002 3:46:30 AM]
correction to apply since they didn't see the original show! Ideally, you'd
shoot a gray card under the stage lights to give them a reference point; if you
can't do that, try to get some close-up shots of the actors showing skin tones.
Then, be sure to tell the lab that you shot the film under tungsten light. It
may take a couple of tries to get color balance that corresponds to your memory
of what the scene actually looked like. (This is why I prefer to shoot slide
film or b&w!)
As to general technique: Use a spot- or center-weighted meter if your camera
has one; otherwise the dark areas around the main subjects will cause the meter
to give too much exposure. (The difference in brightness between the subject
and background is greater than it looks to the eye; lighting designers cleverly
set it up this way to subtly focus attention on the performers!) With a
center-weighted meter, you may have to give a bit less exposure than the meter
suggests -- for negative film, I'd try about -1/3 or -2/3 stops of exposure
compensation. (If your camera doesn't have a spot meter, and you plan to do
much stage photography, eventually you'll probably want to break down and buy a
separate 1-degree spotmeter.)
You'll probably be sorry that your fastest lens maxes out at f/3.5. If you
happened to buy a 50mm normal lens with your camera -- an f/1.8 or f/1.4 or
something -- take it along, too; it doesn't take up much space in the bag, and
can really save your bacon if you want a nice overall shot of a dimly lighted
scene. (Since I photograph a lot of ballet productions, I've had to invest in a
lot of fast lenses so I can get action-stopping shutter speeds: the ones I use
most often are an 85mm f/1.4, a 100mm f/2, a 200mm f/2.8, and for smaller
theaters a 50mm f/1.4 or 50mm f/0.95 -- yes, the latter is a fairly exotic
item! If you keep doing a lot of stage stuff you may want to invest in at least
a fast medium tele such as an 85~100mm f/2 or so; this also makes a nice
portrait lens.)
The tripod is a good idea, although banging it around as you climb up on
catwalks etc. may get annoying. I've tried various other strategies for
steadying the camera while allowing mobility. Sometimes I use a monopod,
especially for shows where I have to stand up to get a good view of the stage.
Often, though, the best solution is to brace either my arms or the camera
itself on the back of a theater seat (obviously this only works if you're
shooting a rehearsal; at a performance, the person occupying the seat may
object!) Backstage or on the catwalks, look around for things against which you
can brace the camera (walls, railings etc.) -- this can often help steadiness a
lot. Just don't lean on stage or lighting equipment that might move, vibrate,
burn you, fall over, etc.! If in doubt, ask the stage manager what's safe and
what isn't.
Hope some of these ideas help. Good luck and have fun!
From: [email protected] (Jim Williams)
==============================================================================
33.08
-< Photographing Soccer Recommendations >----------------------------------------------------------------------------->I am having a hard time shooting Soccer games. Where would be the best place
>on the field to get players in action and what lens would be best?
In my opinion the best place generally is at either end of the field, somewhere
file:///C|/faq.html (346 of 555) [7/19/2002 3:46:30 AM]
between the goalpost and the corner of the filed but closer to the goal. Try to
get as close to the goal line as allowed (without interfering with the play).
There is generally lots of action in the area just in front of the goal and you
should be able to "reach out" for close to frame filling shots of the players
with something like a 135 or 200mm lens. Hold camera horizontal when players
are far and turn it vertical when closer-up. While a zoom may be useful single
focal length lenses have been used for many years before the zooms arrived.
andy, [email protected]
==============================================================================
33.09
-< Sprint Photographic Chemicals >----------------------------------------------------------------------------->I have been in camera stores in Ohio, upstate New York, and in southern New
>England and have never seen the stuff. Where can I get Sprint to try it?
We have been using Sprint as our basic b&w chemistry for a number of years and
are very happy with it. We buy it directly from Sprint:
Sprint Photo Chemistry, 100 Dexter St., Pawtucket, RI, 02860
phone: 1-800-356-5073
fax 401-728-0913
******************************************************************
Professor Steven P. Mosch, Photography Department Chair
Savannah College of Art & Design, 101 Martin Luther King, Jr. Blvd.
Savannah, GA 31402-3146 Phone: 912-238-2469 Fax: 912-238-2436
e-mail: [email protected]
******************************************************************
..............................................................................
Sprint chemistry is sold through The Maine Photographic Reource 1-800-227-1541
or directly from Sprint fax: 401-728-0913
From: clp <[email protected]>
==============================================================================
33.10
-< Artcraft Chemicals - Photo Chemicals Supplier >-----------------------------------------------------------------------------Photographers Fromulary is good, but Artcraft Chemicals will sell you the same
materials for lower (30-40%) prices. He does not have Tech Pan kits, but
carries the chemistry to make up Tech Pan developers. ARTCRAFT CHEMICAL P.O.
BOX 583 * SCHENECTADY, NY 12301 * 800-682-1730 * or 518-355-8700. Ask for a
catalogue and tell Mike Lacobson Maxim sent you <GG>.
Maxim
From: [email protected]
==============================================================================
33.11
-< A few non-US magazine recommendations >-----------------------------------------------------------------------------Here are some non-US photography related magazines recommended by a couple of
PhotoForum subscribers, Peter Marshall and James McArdle:
.............................................................................
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Creative Camera : subscriptions: Cornerhouse Publications, 70 Oxford St,
Manchester M1 5NH, England "a credible, thinking, image-led photography
magazine" USA 50$ per year (institutions 72$) - six issues.
Inscape: William Bishop, 22a Gladwell Rd, London N8 9AA, England. Outside
Europe #15 (international Postal Order or UK cheque) for 5 issues
Camera Austria: Forum Stadtpark, Stadtpark 1, A-8010 Graz, Austria
4 issues AS600 /DM25 /US$ 18.50 This is probably the best of the European
magazines. Like several others it is largely bilingual (German/English).
The following addresses are from some old issues of Perspektief:
Cliches: 36 Rue de Houblon, 1000, BRUSSELS, Belgium
Contretype: 103 rue d'Espagne, 1060 BRUSELS, Belgium
Focus: Utrectsestraat 131 / postbus 15436, 1001MK, Amsterdam, Holland
Foto: Larixlaan 6 / postbus 3, 3830 AA Leusden, Holland
Fotogeschichte: FICHARDSTRASSE 52, D-6000, Frankfurt 1, Germany
Fotografiska Museet: Box 16382, S-103 27, Stockholm, Sweden
GKf- Bulletin: Nieuwe Keizersegracht 58, 1018 DT, Amsterdam, Holland
History of Photography: Taylor & Francis Ltd, 4 John St, London WC1N 2ET, UK
Photographie Ouverte: Ave. Paul Pasteur 11, B-6100 Charleroi/Montsur-M, Belgium
Photovision: Arte y Proyectos Editoriales, S.L., P.O.Box 164, 41710 - Utrera,
(Sevilla), Spain
Peter [email protected]
.............................................................................
and from J. McArdle:
Here are some European magazines.
BEELDING Netherlands ; Maanblad voor kunsten P.O. Box 13097, 2501 EB Den Haag.
10 copies p.a., Hfl 50
BILDTIDNINGEN; Sweden Fotograficentrum, P.O. Box 15310, Stockholm, S-104 65
Brennpunkt; Germany, Berlin Magazin fur Fotographie, Ed., DIBU/LV Berlin im
VDAV, red: Waghauseler Str. 8, 1000 Berlin 31
Camera International France, 51, rue de l'Admiral Mouchez, 75013 Paris
European Photography, Germany ed. Andreas Muhler-Pohle, P.O. Box 3043, D 3400 Gottingen (main texts in English as well as German)
la Recherche Photographique, France Paris Audiovisuel, 35 rue de la Boetie,
75008 Paris
file:///C|/faq.html (348 of 555) [7/19/2002 3:46:30 AM]
the Photographic Journal; Britain Royal Photographic Society, ed. Roy Green,
The Octagon, Milsom st, Bath, Avon BA1 IDN
Perspektief; Netherlands Centrum voor Fotographie, Sint - Jobsweg 30, 3024 EJ
Rotterdam (main texts in English as well Dutch)
Katalog; Denmark, Kvartalstidsskrift for fotografi, Museet for Fotokunst /
Brandts Klaedefabrik, Brandts Passage 37 & 43, DK - 5000 Odense C
even if you can't read the writing you can read the photographs!
Portfolio - published quarterly and is cheap - 18 Pounds subscription Photography Workshop (Edinburgh) Limited, 43 Candlemaker Row, Edinburgh
Scotland EH1 2QB Tel 031 220 1911 Fax 031 226 4287
Photofile - published by the Australian Centre for Photography 3 times a year
and welcomes articles, publishes reviews of Australian photomedia - address:
257 Oxford St., Paddington, NSW 2021 Australia. subscription-tel: 02 331 6253
Platinum Portfolio - quarterly - PO Box 184 Artarmon NSW 2064 Australia.
Metro Education - devoted to Media Education but of interest especially to
teachers of photography - ATOM P.O. Box 222, Carlton South, Victoria,
Australia 3053 , tel 03 482 2393, fax 03 482 5018
Another Australian mag is "Black and White" about which I have mixed feelings while its very beautifully produced, it is actually published by a company that
specialises in fashion magazines and its emphasis is on rather strenuous nudes
in the neo-national-socialist vein. Lots of oil and fashionably correct
bodies. But in between there is some excellent photography and, while the
pretense of being a 'serious' art photography magazines sometimes becomes a
bit transparent, most photographers I know seem to respond to at least some of
the images as being groundbreaking stuff. Address: Studio Magazines, Level 3,
100-111 William St., East Sydney 2011, tel.(02)360 1422, fax(02) 360 9742.
Issued monthly. $A90.00 subs.
Note 34.01
-< Accounting for extension tubes and exposure factors >------------------------------------------------------------------------------->I just bought a set of extension tubes for my medium format camera. The short
>tube requires an exposure adjustment of 2X, the longer one 3X. In terms of
>exposure stops ie: full f-stops OR shutter speeds, can someone explain to me
>how to adjust the exposure for each tube and when the tubes are used together.
If you are using a plain extension tube (absolutely no lens elements in it) the
amount of exposure adjustment is dependent upon BOTH the length of the
extension tube AND the focal length of the lens being used with it!!! In other
words, using a 25mm extension tube with a 50mm lens is a different exposure
adjustment than using the same 25mm tube with a 200mm lens.
You can use this table for your calculation of exposure adjustment.
Extension / focal length
file:///C|/faq.html (349 of 555) [7/19/2002 3:46:30 AM]
Exposure increase in EV
or f/stops
1/10 - 1/5
1/4 - 1/3
1/2
1
1.5
2
1/2
1
1.5
2
2.5
3
If you're into the real math, you can calculate the Exposure Factor (not the
same thing as exposure increase in the above table... Exposure Factor 4 =
exposure increase of 2 f/stops, for example).
EF = (Magnifaction+1)^2
where Magnfication = Extension / Focal Length. We can convert both into a
single equation for simplicity:
EF = ((Extension / Focal Length)+1)^2
Got that? <s>
--Wilt
From: [email protected]
...............................................................................
One of the easiest and most versatile ways to make exposure compensations for
longer than normal lens-to-film distances, or "bellows extension", as it is
often called, is to use a variation of the inverse square law.
To do this, you will have to measure a standard distance from a point on the
lens to the back of the camera. This "standard distance" MUST be equal to the
focal length of the lens you will be using with the tubes. For example, you
mentioned MF, so I'll assume an 80 mm lens. Measure from the back of the
camera to a distance of 80 mm, and note that point on the lens. This is your
normal lens to film distance, or "old extension, as they sometimes say. Now
put on the longest tube you have, and measure that distance again. Let's say
it's 140 mm now. Note: the longest tube will give you the difference between
the two numbers. You actually use whatever will do the job.
The formula is: the new lens extension squared divided by the old lens
extension squared, or 140 squared divided by 80 squared, or 19600 divided by
6400, or 3.06. "3" is certainly close enough. That translates to a one and
one half increase in exposure. So if the meter says shoot at f/11, it's one
stop, or twice the exposure, to f/8, and if you want twice more, or four times
altogether, it would be f/5.6. You want a point in between 5.6 and 8 to equal
a three times increase.
This will become second nature in no time. The nice thing about it is that it
works for 35mm cameras and normal lenses, or wide angle or telephoto lenses, or
4 by 5 cameras with the bellows racked out 3 miles, or what ever else you may
be working with. You can make extension tubes of old paper towel tubes, and it
will work flawlessly. It works for my Robertson Meteorite copy camera, which
takes up to a 15 by 18 inch negative. And it works exactly the same for every
conceivable situation.
Summary: take the new focal length of the lens, or the new extension, square
file:///C|/faq.html (350 of 555) [7/19/2002 3:46:30 AM]
it, (or multiply it by itself if your calculator doesn't have an x squared
key), and divide that by the old focal length, or *actual* focal length,
squared. That is your exposure factor. Increase exposure that much, and you
can't miss. Works every time, unless you really go overboard and start getting
into reciprocity failure.
Math, yes, but if you want to do some serious closeup work without in camera
meters, it's a necessity, especially for slides.
John Thompson, Canton, Ohio
From: "John D. Thompson" <[email protected]>
..............................................................................
There are probably many ways to arrive at the answer you are looking for. I
would approach it from the point of view that a factor of 2 is one stop. I also
know that the log of 2 is .3
From here, if I need an exposure increase
associated with a factor of 2x I find the log of this factor and divide it by
.3 to find the increase in terms of stops.
For example: need an increase of 2x. The log of this factor is .3
divided by .3 the answer is 1 stop
"
"
"
3x
The log of this factor is .47
divided by .3 the answer is 1.6 stops
now I if I place both tubes on the camera and use the two "factors" together,
their "power" is multiplied. This is because if I need a factor of two and add
a stop, and then I need (for some reason) another factor of 2 on top of that
I'd open up another stop. The total would be two stops or a factor of 4. Thus
factors get multipled. In the case you mention, 2 x 3 = 6 and thus to continue:
For example: need an increase of 4x. The log of this factor is .6
divided by .3 the answer is 2 stops
"
"
"
6x
The log of this factor is .78
divided by .3 the answer is 2.6 stops
etc.
andy, [email protected]
...............................................................................
================================================================================
Note 34.02
-< Developing Tech Pan film recommendations >------------------------------------------------------------------------------->Does anyone have any suggestions for developers with Kodak Technical Pan? I'm
>a scientist and use it in microscopy because of the low grain. I also use it
>at home for wildlife and macro work. I currently use Rodinal which brings ASA
>up to around 50. Any suggestions?
I have had considerable success with modified POTA developer. Formula follows:
water (125 F)
Sodium Sulfite (anhyd)
Kodalk
Phenidone
Benzotriazole 1% sol.
Water to
750ml
25 gm
1.0 gm to 1.5 gm
1.5 gm
15 ml
1.0 l
file:///C|/faq.html (351 of 555) [7/19/2002 3:46:30 AM]
The activity of the developer changes wit its oxidation state and it should be
used immediately. This is inconvenient for two reasons; first, the warm water;
second, Phenidone is very hard to dissolve. So I make a 5% solution of
Phenidone in denatured alchohol (or in 99% Isopropyl Alchohol if you can get
it) and a 2% or 5% solution of Benzotriazole in denatured alchohol. Both of
these chemicals are readily soluble in alchohol.
Using these premixed solutions, I can then mix the developer at normal
processing temperature and immediately use it. Processing time is about 15
minutes at 20 C (68 F), with 30 seconds initial agitation and 2 seconds shake
every 30 sec. (as advised for Technidol liquid). This produces a useable EI
of 25 or 32.
I have heard that a useable EI of 50 is possible if TechPan is developed in
Flexicolor (Kodak's C41) developer. I have not tried it.
In 1982, I produced an excellent metol-based divided developer that produced
beautifully graded negatives at EI 40. Processing consisted of diluting a stock
solution for the first solution, processing for three minutes with continuous
agitation, then replacing the first solution, without rinsing, with a
sulfite/carbonate solution for three minutes with continuous agitation. If
anyone's interested, I can dig it out and post it. (or send it to you)
Tech Pan is a bit fussy, but it is a truly beautiful pictorial film, especially
if you enlarge to billboard size. The limiting factor with this film is your
optics and technique, and not the film. Best of luck!
_/_/_/_/ _/_/
_/ _/
| Edward M. Lukacs
_/
_/ _/ _/_/ _/
| [email protected]
_/_/_/
_/ _/ _/ _/
| 11286 Southwest 169 Street
_/
_/
_/ _/
| Miami, Florida 33157 USA
_/_/_/_/ _/
_/ _/_/_/_/ | Telephone: (95) 305-235-9098
...............................................................................
Try using TMax developer at various dilutions. My notes on this are at home so
I can't be too specific, but I suggest you try dilutions of 1:14 to 1:19,
development in the 6-10 minute range, and rate the film at 16-25. My impression
of my experiments with TMax was that there was good control of contrast, good
consistency over several rolls developed over a number of weeks, and
development was very even. I was able to use my normal agitation method rather
than lowering films into the tank as Kodak recommends for Technidol.
There is a good article in the March/April 1992 issue of "Darkroom and Creative
Camera Techniques" on processing Tech Pan. Among other things it suggests using
Kodak Flexicolor developer, 10 minutes at 20 degrees C. Rate the film at 50.
There is also a formula for a stop bath for this procedure. I've done it a few
times with satisfactory results, although you may want to rate the film at 20
rather than 50.
John Poirier, Coordinator of Technical Services, Northwest Territories Archives
Yellowknife, Northwest Territories, Canada [email protected]
...............................................................................
I have been using C-41 Flexicolor developer with Tech Pan for normal contrast
file:///C|/faq.html (352 of 555) [7/19/2002 3:46:30 AM]
work for some time and have been quite happy. It seems less prone to producing
the development problems I experienced with other developers, especially with
120 film. It is certainly cheaper than Technidol and does not require any fancy
mixing. I originally read about it in an article in _Darkroom Techniques_, by
Hans Dietrich. He claimed an ISO of 50, but I get about 25-32.
My procedure:
1.
2.
3.
4.
5.
Pre-soak the film about 2 minutes in water, with intermittent agitation.
Dump the water, turn out the lights, and remove the lid and film.
Pour the developer into the tank.
Drop the film into the tank of developer and replace the lid.
Agitate by inversion for 30 seconds. Agitate 5 seconds every 30 seconds
for the full time (9 minutes at 68 degrees F).
.....continue as usual..
As with conventional films, and at least as important, make sure there is a bit
of air space between the top of the solution and the lid. This ensures that
there is adequate turbulence during agitation.
I use No.2 paper and a cold light/diffusion enlarger head. I have read that
the grain of Tech Pan is so fine that it is not subject to the Callier effect,
so this development time may work for condenser enlargers, too. As you
probably know, Tech Pan is sensitive stuff, so your results will likely vary
from mine.
. ****************************************************************
. *
Nathan Prichard
*
Kentucky Historical Society *
. *
Internet/e-mail:
*
Box H
*
. *
[email protected]
*
Frankfort, KY
40602
*
. *
*
U.S.A
*
. ****************************************************************
...............................................................................
From: Jim Thyer <[email protected]>
The developer given by Ed Lukacs is very similar to a developer I have used in
the past. It is the "Delagi No 8 Developer" and I fount it in an article in (I
think) Popular Photography, (the magazine name is not on my copy) but it was
in the April 1981 issue. The only variations on the formula above are:
Use Kodalk OR Borax
Phenidone
0.8 gm.
(May be 1 gm. Kodalk gives slightly higher
contrast, Borax yields good developer activity)
1.4 gm.
Use at 68 deg F, 15 minutes, use a liquid level about twice the height of the
film reel or reels for best results. Suggests 32 to 64 ASA rating. Good film
for detail, been around a long time (since 1977 as SO-115) and suprisingly
few photographers have heard of it. I really enjoy the clear base and the
fact it lies flat, as well as its minimum grain.
************************************
Jim Thyer
[email protected]
Physics, School of Info Technology & Math. Sciences
University of Ballarat
Ballarat Vic 3353 Australia.
file:///C|/faq.html (353 of 555) [7/19/2002 3:46:30 AM]
Ph 053 279 236 int 61 53 279 236
************************************
================================================================================
Note 34.03
-< Managing Polaroid Type 55 Pos/Neg film in the field >------------------------------------------------------------------------------->My question to all you pros is: How do you handle Polaroid 55 P/N negatives
>if you are on a shoot outdoors away from sinks and trays and running water
>etc. Anyone who has some ideas on the best way to preserve the negs under
>these conditions please give me the benefit of your experience.
According to the Polaroid publication "Instant Innovations: Creative Uses for
Polaroid Films" Mark Hauser of Chicago developed this approach to preserve
Type 55 negs in the field appropriately sized plastic food containers (e.g.
Tupperware) about 2" high:
1. fill container with cold water & sodium sulfite solution
2. place two thin sponges on the bottom & cover with cold water
3. place a 4"x 5" piece of plain white paper towel (no design, no embossing) on
top of the sponges
4. stack negs emulsion side down with a paper towel between each one
5. add two more sponges to top of "sandwich" before sealing with container top
After returning to base, treat the negatives in fresh sodium sulfite solution
and continue processing as indicated by Polaroid
The publication itself should be readily available thru a phone call to
Polaroid's technical assistance people. The number I have is 1-800-225-1618. So
far I've found the people there very helpful (even got a couple of free packs
of 669 once as replacements for problems).
If you're really into carrying a lot of stuff around and making your shoot even
more difficult, you might consider as an alternative the clearing tank marketed
by Graphic Designs (Shutterbug advertiser) which is a one gallon plastic bucket
and lid along with a plastic sheet film holder that doesn't really adjust to
the Type 55 neg size. The idea is to cart along the sodium sulfite solution &
pop your negs into the holder immersed in the solution as you are shooting. Of
course, you'll need a way to clean the stuff off your hands and anything else
it hits since it dries to a nasty white dust.
Or, if your 545 holder isn't too cantakerous, you can re-insert the covering
after exposure and remove the entire sheet without processing. Then reload the
exposed sheets into the holder later for processing. This is a method suggested
by Adams.
With the pack film equivalent, I exposed outdoors for some winter scenery
shots, then left the tripod outdoors, brought the film inside before pulling &
kept the sheet under my arm to bring it up to temp during the processing time.
If you are going to process in the field, you should pay attention to the
temperature. Polaroid is good but demanding stuff. It's really sensitive to the
thermometer.
Roy C. Zartarian, [email protected]
...............................................................................
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A plastic bucket with a lid that gives a water-tight seal is available from
Graphic Center, PO Box 818, Ventura, CA 93002 (phone 805-641-1625). The bucket
comes with a rack that holds about a dozen 4X5 negatives, and with a supply of
sodium sulfite. Graphic Center calls this bucket the PN-10 Clearing Tank. I got
mine in 1990: the price then was 26.95, plus 5.00 for S&H.
--david "[email protected]"
...............................................................................
Invest seventy-nine cents in a small Tupperware or Rubbermaid container large
enough to hold the 4x5 negatives. You can use the sandwich sized ones or try
to find one that opens vertically.
Mix the sodium sulfide solution to clear the negatives. Pour into the
Tupperware container. As you make pictures, inspect the positive. Put the
keepers in the sodium sulfide solution. When you finish for the day, pull out
the negatives, they shouldn't stick together in the solution and it's
impossible to "overfix" the things and wash them.
-fred, [email protected] (Fred Collins)
..............................................................................
... I've always prefered to cart around a container of water rather than the
sodium sulphite solution. I then clear in sodium sulphite when I get home a few
hours later. I think the Polaroid literature says you can leave the negs in
ordinary water for up to 72 hours before proper clearing.
Philip Jackson, <[email protected]>
..............................................................................
I have encountered many of these same problems as you gents are describing.
Shooting type 55 in the field can be quite tricky. I have found what works
best for me and am glad to share it with you. First I learned the visual
relationship of what a good negative means a good positive will look like. I
usually find that the positive is 3/4 to 1 full stop lighter than a properly
exposed negative. When shooting in the field, I shoot off one exposure as a
test and judge it mainly from the positive. I trash the negative. When
assured that my exposure is correct, I shoot my final and carefully remove it
from the holder WITHOUT ROLLING THE DEVELOPER!! If you press the release
button you can remove the film with out developing. I have been told by my
friendly polaroid rep that the latent image will not degrade in quality for
over 2 months at least. I have made exposures and not developed them until
returning to my studio over a month later. This saves me all the hassle of
protecting and clearing negs while on the move.
If anyone else has found anything better, please let me know.
[email protected]
================================================================================
Note 34.04
-< Pinhole Resources and the Hole Thing >--------------------------------------------------------------------------------
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A good basic book on pinhole is Jim Shull's The Hole Thing , there are examples
of cardboard box cameras which you could duplicate in wood. There is also The
Pinhole Journal Star Route 15, Box 1655, San Lorenzo, NM 88057 you may want to
contact. I believe they also sell inexpensive, beautifully designed wooden
pinhole cameras sizes 4x5 and up.
From: clp <[email protected]>
...............................................................................
Try The Pinhole Resource, Star Route 15, Box 1355, San Lorenzo, NM 88041
505-536-9942. They have a catolog and a magazine dealing with Pinhole
Photography. Quite an interesting Magazine. Good Luck
Shaun, Camera Graphics Photolab, Albq NM 87106
================================================================================
Note 34.05
-< Multiple Exposure Capability - what good is it? >-------------------------------------------------------------------------------> I just got a camera with multiple exposures capability. When do you
> need to use this function and how ? Do you need a special filter so that
> your second/third exposure does not superimpose on top of the first ?
Well, if you don't want additional exposures imposing on the previous exposure,
just don't use the multi-exp feature at all.
'Course there's other handy uses of ME such as running a few distance checks on
your TTL auto flash ranges in a church or auditorium. If you use ME you can do
a bunch of tests and only waste a single frame of film.
Another use is to compile a long exposure from several pieces, allowing the
shutter to close if people walk by, lights glare, etc. If you want to paint
with light by flash, you can let the shutter close between exposures to avoid
background or stray light building up while waiting for flash recycling.
Regards, David Rosen [email protected]
...............................................................................
There are bunches and bunches of ways to use multiple exposures. One that I've
been doing a lot in the lab I work in (an astronomy lab, not a photo lab) is to
take pictures of equipment. I set the camera up on a tripod, meter, and stop
down by a stop or so. The first exposure I do with the equipment case on. The
second exposure is with the case off the equipment. This results in a ghostly
case showing both the outside of the equipment, as well as the inside. Very
nice for documenting something you've just spent the last two weeks slaving
over with a soldering iron. ;)
Another use I've had for multiple exposures in the lab is in tracing laser
paths. The first shot is metered on the room with the room lights on, and taken
as such. For the second shot I kill the room lights and open the shutter. I
then go around the room and "paint" out the laser beams with a white index
card. Part of what our lab does is to manufacture diffraction gratings, so
after a beam diffracts off of one of our gratings we wind up with hundreds of
beams. They make for some very pretty, as well as useful pictures.
file:///C|/faq.html (356 of 555) [7/19/2002 3:46:30 AM]
Play around with your multiple exposure function. It's lots of fun, and an easy
way to finish off a roll.
Tom
From: [email protected] (Tom Benedict)
Organization: McDonald Observatory, University of Texas
............................................................................
Indeed, there are such filters. They shut one half of the lens. You can get
very funny results, for example when you set the camera on a tripod and focus
it on a bench. First you take the one half of the picture with a person sitting
on the bench on this side. Then you turn the filter round and take the other
half (2nd exposure) with the same person now sitting on the other side of the
bench, in different clothes or so. (some irrelevant material deleted)
But you can also use ME without filter. For example, you can photograph a
painting in red light, then -slightly move the camera- in blue light and then
in green light. You must underexpose each shot here. The results are quite
nice.
Marc
From: Marc Werner <[email protected]>
Organization: RWTH Aachen
..............................................................................
In Marc's posting above what he probably is actually refering to is not exactly
a filter but rather a mask. A filter which is opaque on one side. This prevents
the film from being exposed on 1/2 the frame especially if small apertures are
used.
Actually such a mask is probably better referred to as a matte, and the device
when made into an accessory, a matte-box. In matte-box photography positive and
negative masks are used to block and expose various areas of a scene
sequentially. A camera capable of multiple exposures is very necessary for
technical perfection of this technique. Sometimes even the slight vibration
introduced into the camera body as the shutter and mirror do their thing is
enough to slightly move the film between shots. In such cases a pin registered
camera may be called for.
Andrew Davidhazy, [email protected]
================================================================================
Note 34.06
-< How are higher flash sync speeds achieved >------------------------------------------------------------------------------->Would someone explain to me how the newer cameras sync faster than the
>customary 1/60 (horizontal) and 1/125 (vertical fp shutter.) please? Do they
>slow down the flash pulse so that it cover the entire "swipe" of the fast fp
>shutter, or a number of strobe pulses along the full swipe of the fp shutter
>or what?
None of the above, if you mean the faster X-synch speeds. The shutters blades
simply move a whole lot faster. This means the film gate is wholey open for
exposure at shutter speeds higher than previous designs allowed.
Curtain shutters traveling across the long dimension had, in past decades,
file:///C|/faq.html (357 of 555) [7/19/2002 3:46:30 AM]
X-synch speeds of 1/25, 1/40, 1/60, 1/75, and 1/90. The higher X-synch speeds
are on the newer, faster moving curtain shutters. The vertical running bladed
shutters have X-synch at 1/90, 1/100, 1/125, a 1/200, 1/250, and 1/300. The
trend is the same. The faster X-synch speeds tend to be the newer shutters.
This is due to stronger, lighter and faster-moving blades having to clear only
the shorter dimension of the gate.
Regards, David Rosen dr8192@albNYvms or [email protected]
..............................................................................
Faster FP sync speed are accomplished two ways as far as I can determine. The
first is that modern shutter "curtains" travel significantly faster than the
older designs and this allows cameras to raise the standard X sync speed by a
factor of approximately two or possibly four.
No FP camera, however, can sync with all flashes up to their highest shutter
speeds because at these speeds the full frame is not exposed all at once but is
exposed sequentially through the moving shutter "slit" created by the curtains.
Cameras that DO allow sync up to the top speeds must be used with special
flashes that flatten out the output of the flash by going into a "stroboscopic"
mode flashing at a rate of maybe 10K to 20K flashes per second for the time it
takes the leading curtain to go across plus the exposure time chosen. This
system is used in such cameras as the Olympus OM-4T. I did some testing of
this system when it first came out many years ago.
Newer flashes MAY employ a different scheme. I believe you can retreive a text
file with how this test was performed from an "archive" of articles available
at a site here at RIT. To check out what is available send a message to:
[email protected] stating in the Subject: line _and_ message body: articles$txt
Andrew Davidhazy, [email protected] at RIT's High Speed Photography Lab
================================================================================
Note 34.07
-< Front projection for professional backgrounds >------------------------------------------------------------------------------->I have seen photographs where people are shown posed in front of a background
>of mountains, hills or other picturesque scenes. How is this done?
Generally, if done photographically it is done using a system known as
front-projection. A front projection system projects an image of a scene onto a
highly reflective screen along the same optical axis as the lens of the camera
by using a beam splitting mirror placed in front of the lens. The mirror is
aimed at the slide of the scene placed in the projector located generally
ahead and below the camera's lens. Sort of like this:
semi transparent mirror
\<-flash or
|
.--|--------|--.
------> /
\ ambient light|
|
|
/
\
\ <-' |
high
| from subject |____.
/
\ 0
\
| reflectivity
| __________________|________/_________________\000
\
|
screen |
|
|
/--->------>------->--0
\ | <---------'
| -<--------<-------+-<--/-|--->--<--->--<---->--<---->--<-|
| from backgnd _____| /
|
00
\|
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|______________|
/
^
0 000
/|
|
0
/ |
camera
|
/ |
.---+---.
/
|
|
|
|
^
|
|
|
|
|
.--|
---.
|
projector
|
|
|
low reflectivity
|
|
|
subject
| =========== |
|
slide
|
------------The light from the projector is weak enough that most subjects do not reflect
enough light back to the camera to be visible. On the other hand the light that
falls on the screen is "retroreflected" back to the projector and the camera
lens also. The screen is a fairly specialized one I believe mostly made by 3M
and sometimes referred to as Scotchlite. It is not cheap! Standard projection
screens are not reflective enough.
/
Hot lights or flashes lighting up the scene from angles other than the optical
axis do not affect the retroreflected light from the screen and mostly affect
only the lower and non directionally reflective surfaces of "standard" subjects
such as people, etc.
Although there are several front projection system manufacturers I happened to
remember the one called the Scene Machine. Often this is the system used by
photographers making High School prom portraits and other similar events.
Customers choose the background they want and the photographer simply changes
the slide in the projector. Flashes are used for illumination in these set-ups
and the projector is also typically fitted with an electronic flash that goes
off at the same time as the main units.
The photographers must make sure that the alignment between projector and
camera lens is properly set. There also is concern about the focal length of
the projector vs. the lens used in the camera.
Andy, [email protected]
..............................................................................
Just to add another comment from 30 yrs of experience with these systems. Cost
is high for the screen material, from $1500 upwards for one mounted on fiber
glass which is probably all that has kept them from being in universal use.
The systems were used for commercial work years before Henry Olds (Scene
Machine) made them popular for high school seniors and proms. The financial
advantage is in year around "seasonal assignments" in the air conditioned
comfort of a studio. The better systems use 2-1/4 slides so quality can be
quite high. While some claim to see a "line" around the subject, I'll assure
you that any such lines are the result of poor lens alignment at the beam
splitter or not enough distance from the projecting lens to the beam splitter.
The most effective use is not front projection alone but in "sets", for
example, a subject seated in front of a window (frame prop) using the screen
image in back of the set for the view ...or a subject touching a real tree
branch (cut and hanging on a light stand) with the projected image filling the
background. There can be far more to the creative work than selecting a slide.
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By taking advantage of the two different angles available (camera-slide and
camera-subject) you can take a subject coming out of a pool with water in the
background instead of the usual fence and chair clutter or, another example,
take a subject in front of a fireplace with the option of positioning the
"fire" instead of having it blocked as so often happens in the usual single
angle photography. Everyone has seen hundreds if not thousands of these images
but few recognize the angle distinctions. Because people can't see from two
completely different angles at the same time, this earlier version of "virtual
reality" is accepted without question!
Email if you are in need of specific info or a sample print for a project.
J.M.Conway, [email protected]
================================================================================
Note 34.08
-< Desensitizing film for development by inspection >-------------------------------------------------------------------------------> I was reading darkroom cookbook column in "Camera and darkroom" and saw that
> in one of the back issues there was an article on development by inspection. I
> thought this technique had been thrown out years ago!! Does anyone have any
> information regarding formulas for emulsion desensitisers and safelights etc.
I used to use Kodak Desensitizer. It's a purple dye. About a gram of powder
(that's all you used to get for over $20, and this was 20 years ago, or so)
makes a quart of reusable solution.
You soak the film in it, then you can inspect it under a green safelight
several times throughout development. I used to push high-speed recording to
over 16,000 ASA (I mean ISO). I would shoot rock concerts (they had low light
in those days) at 1/30 sec. (or faster if needed), then push the film 'til I
saw the proper image while inspecting. Sometimes I would resort to sticking it
in warm Dektol. Obviously, sometimes it would fog, but the "flash" actually
helped reduce the high contrast. Ah, the good old days.
David E. Le Vine
..............................................................................
Safranin-O, a chemical closely related to, but more effective than
Phenosafranine, a well known desensitizer, is available at virtually any
chemical supply house. It is normally used as a biological stain, but is a
fine desensitizer. Any text on photochemistry, or the Photo Lab Index can
provide you with an appropriate formula and use instructions.
As an added feature, addition of phenosafranin to developers containing
hydroquinone as the sole developing agent results in causing the hydroquinone
to function as a soft-working developer. When Metol was very expensive, use of
a small amount of this dye with much cheaper hydroquinone produced the same
development action at much lower cost.
Also, in my experience, Safranin-O is cheaper than Kodak's desensitizer.
From: Edward M. Lukacs, [email protected]
================================================================================
Note 34.09
-< How much light does it take to expose film properly? >file:///C|/faq.html (360 of 555) [7/19/2002 3:46:30 AM]
------------------------------------------------------------------------------->Do you know the formula for exposure? It must be a function of shutter speed,
>aperature, exposure index and light levels. I guess light levels would be
>measuredin footcandles or lumens. I know this isn't strictly linear.
First, Exposure is a function of Illuminance times Time. Illuminance being the
amount of light falling on the film (as opposed to Luminance which is how much
light leaves the subject). Exposure itself is linear. The photographic response
in terms of Density is not.
Going further, it is possible to determine the light level to necessary to
properly expose an average scene on a particular film. This is given by the
following relationship:
25
times
F# squared
Foot/Candles required = ----------------------------ISO
times
exposure time
The number 25 is a constant that "guarantees" that you will end up with
properly exposed negatives of average scenes. Sometimes slight departures from
this particular value are used depending on whether you like your negatives to
be thinner or denser than those given by using 25.
If you work this out to its logical conclusion you will find that the Sunny-16
rule assumes that there are about 6,400 foot-candles of illumination on a
standard scene for it to reproduce properly on average films at an aperture of
f:16 and an exposure time equal to the reciprocal of the ASA speed of the
material.
andy, [email protected]
================================================================================
Note 34.10
-< What is a diopter? >-------------------------------------------------------------------------------> Can anybody explain to me what the diopter is? Thanks.
A diopter is a a focal lenth measurement used by opticians for specifying eye
glasses. A diopter is the reciprocal of the focal length in meters. Some
close-up lenses are specified in diopters, e.g., a +2 closeup lens is a
positive lens with a focal length of 2 diopters or 1/2 meter. The lenses that
are used to adjust a viewfinder to match your eyesight are called 'diopters'
because that's way they are measured.
Orrin - Long Island, NY | [email protected]
[email protected]
| [email protected]
================================================================================
Note 34.11 -< Daylight balanced fluorescent tubes and correction filters >------------------------------------------------------------------------------->Does anyone have information on the color balance of various fluorescent tubes
>which fit standard shop light fixtures available in hardware stores? Is there
>a site on the net where this info is available. I'd like to use them as fill
>occasionally for both still and video shoots.
I get mine from: Duro-Test Lighting, 9 Law Drive, Fairfield, NJ
Their toll free customer service number is: 800-289-3876
file:///C|/faq.html (361 of 555) [7/19/2002 3:46:30 AM]
07004
I use the Optima 50 model for daylight balanced light boxes and
overhead lights for viewing color prints, but I would guess they
would be appropriate for shooting with also.
Dirk M. Schuneman, owner First Photo Lab, Orlando, FL, USA, Photo [email protected]
...............................................................................
Flourescent tube manufacturers have tubes they consider to be daylight balanced
(ie:Chroma 50's) and tungsten balanced (ie: warm white deluxe) but from my
experience on film they aren't even close. Roscoe (movie supply company) makes
a magenta gel in large sheets that you can wrap cool white bulbs in that gets
them very close to daylight. Thats about the best match I've found (the light
looks very pink to the eye but neutral on film). They also have a gel you can
put over your strobes to convert them to cool white if you want to go that way
then filter on the camera.
Tom Collicott, [email protected]
================================================================================
Note 34.12
-< How are the faster X sync speeds achieved these days? >------------------------------------------------------------------------------->Would someone explain to me how the newer cameras sync faster than the
>customary 1/60 (horizontal) and 1/125 (vertical fp shutter.) please? Do they
>slow down the flash pulse so that it cover the entire "swipe" of the fast fp
>shutter, or a number of strobe pulses along the full swipe of the fp shutter
>or what? Thanks in advance ... chuck
Faster FP sync speed are accomplished two was as far as I can determine. The
first is that modern shutter "curtains" travel significantly faster than the
older designs and this allows cameras to raise the standard X sync speed by a
factor of approximately two or possibly four.
No FP camera, however, can sync with all flashes up to their highest shutter
speeds because at these speeds the full frame is not exposed all at once but is
exposed sequentially through the moving shutter "slit" created by the curtains.
Cameras that DO allow sync up to the top speeds must be used with special
flashes that flatten out the output of the flash by going into a "stroboscopic"
mode flashing at a rate of maybe 10K to 20K flashes per second for the time it
takes the leading curtain to go across plus the exposure time chosen. This
system is used in such cameras as the Olympus OM-4T. I did some testing of
this system when it first came out many years ago.
Newer flashes MAY employ a different scheme. I believe you can retreive a text
file with how this test was performed from an "archive" of articles available
at a site here at RIT. To check out what is available send a message to:
[email protected] stating in the Subject: line _and_ message body: articles$txt
andy, [email protected]
================================================================================
Note 34.13 -< How to adjust the tension on a Graflex Focal Plane shutter >-------------------------------------------------------------------------------How to tension the Graflex Focal Plane shutter
This How To is for those who recognize that the rewards of learning how to "do
file:///C|/faq.html (362 of 555) [7/19/2002 3:46:30 AM]
it yourself " must be weighed against the risk of potential failure. Don't
risk ruining your Super D if you aren't sure ! ;-D
INTRO
By now the old and venerable spring in your RB auto Graflex or Series D has
lost its luster and doesn't pull the curtain fast enough. As a result, all
speeds are slow. Fortunately the fix is not too difficult for those with a
little patience and mechanical aptitude:
PROCEDURE
1. First make sure that the curtain is not rubbing anywhere and the curtain
selector is free to move (they often get bumped and then stick). It should
move very freely with no sticky spots.
2. Apply just a drop of lightweight oil into the two oil holes. These are the
little holes in the end of a round, flat, keyed metal piece on the left hand
side of the camera. Don't ever use or spray WD-40 or any spray lube or it'll
get in and mess up the works. Just use one of those little needle oilers like
the one sold in Radio Shack. Check to see if this improves things dramatically
- probably not ;-)
3. Look at the tensioning escutcheon (that's the plate that surrounds and
holds the tensioner) You'll see the tension knob, the release button and a hex
shaped cap. You should also see screws at the perimeter of the plate-don't
undo these yet. Release tension with the release button now. Then just take
off the hex cap (counterclockwise) to reveal the screw slot.
4. Find the right screwdriver to fit the screw slot before proceeding. Notice
that as you tension the shutter, the screw slot rotates. This slot is at the
end of the tensioning shaft and has to be tightened in order to increase the
spring tension. Don't try to force the screw since it's locked in place
relative to a gear under the plate.
5. Loosen, but don't remove, the screws holding the plate down. On the Series
D there are four screws. The idea here is to lift up the plate enough so that
the gear disengages from the shaft so that you can retension it. Put a thin
screwdriver in to hold the slot BEFORE you lift up the plate so that the
tension doesn't release suddenly.
6. You may have to unscrew the perimeter screws a little more to disengage the
gear. Once accomplished, now is the time to guess how much more tension to
apply by turning the slot so that it gets tighter. I'm impatient so I give it
a good whirl thereby throwing caution to the wind. This can result in too much
tension which could overly stress the now ancient shutter curtain material, so
you probably should try moderate tensioning first. If the spring has lost its
temper, it will feel "dead" when you turn the screw - this is not the case and
the spring has some life left in it.
7. While still holding the tensioning slot push the plate back down to engage
the gear. Re-tighten the perimeter screws. Put the hex cap back on after
applying one drop of oil.
8. Test the shutter. I usually test with Polaroid having found the speed to
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be reliable enough, however, if you have a flash meter you could make a setup
with a bright light to measure the relative shutter speeds.
9. You may have to go back and do this again. Be patient, don't poke or pull
on the curtain in frustration, and don't curse me 'cause it's really easy and
self evident once you dive in.
FINAL COMMENTS
I love these old boxes and with care they ought to be useful tools for the
serious photographer. I am still learning the ins and outs so I don't claim to
be an expert by any means but I have found this procedure to be workable
several times now with no failures yet.
PS - I've been asking around about how to convert some of these to Graflok
backs, a challenge that I have not attempted yet but will tell you about my
experiences and write a "how to" if there is any interest.
Bob Crowley, Staff Inventor, Input Devices, Wayland MA, [email protected]
================================================================================
Note 34.14
-< How does a teleconverter change Depth of Field? >------------------------------------------------------------------------------->If you use a 2x converter with a primary lens at, say, f/22, will you get the
>same DOF (Depth of Field) as the primary lens on its own at f/11?
No! Let's do the math.
1. Put simply, depth of field is a function of image magnification and f/stop.
2. Image magnification and lens focal length can be compared one to one. In
other words if you double the lens focal length the magnification will also
double.
3. The change in DOF due to magnification is best described by the inverse
square law. a 2x factor change in magnification produces a 4x change in DOF.
Increase magnification and DOF will decrease.
4. F/stop values are relative to focal length. Increase the focal length
without altering the size of the aperature and the relative f/stop value will
change (increase/decrease?) (f/22 goes to f/45 with a 2x increase in focal
length).
5. DOF changes due to f/stop do not conform to a fixed scale -- it's a log
scale. At smaller aperatures the change is greater. In other words the percent
increase in DOF produced by the change from f/22 to f/32 is greater than the
percent increase produced by the change from f/5.6 to f/8. To rough it out with
mid range aperatures considered, the change in DOF due to a full f/stop change
is between a factor of 1.3 to 1.6.
Now then. You've got a 100mm lens (35mm camera -- circle of confusion .00125
inches) set at f/22 and focused on a subject 5 feet away. The DOF is 13.8
inches. Switch to a 200mm lens at f/22 and do not move and the DOF decreases to
25% of the previous case -- 3.5 inches. (Obviously you're cropping the image
more tightly -- you have less information as magnification has doubled). Now
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stop the 200mm lens down to f/45 (two stops) and the DOF increases to 7.7
inches or about half of what the 100mm lens produced at f/22 at the same
distance from the subject.
Let's do it with 2X converters: Take a 100mm lens at f/22 focused on a subject
5 feet away as a starting point (13.8 inches of DOF). Add a 2X converter and
the focal length increases to 200mm. The relative aperature is reduced (see #4
above) by two stops. If the f/stop setting on the lens (really a 100mm) reads
f/22 -- it is in effect f/45. If you do not move the camera position, DOF will
be 7.7 inches or roughly half of that produced by the 100mm lens at f/22 at the
same distance. If you compensate for exposure and set the 100mm lens to f/11
therefore achieving an effective relative aperature of f/22 for the now 200mm
lens the depth of field will drop to 3.5 inches or only 25% of that produced by
the 100mm lens at f/22.
Do the math.
Where N = near limit DOF, F = far limit DOF, H = hyperfocal distance, D = film
to subject distance, and L = focal length: N = HD/H+(D-L) and F = HD/H-(D-L).
Joe Angert, <[email protected]>, St. Louis Communiy College
..............................................................................
It seems to me that if you make a photograph at the same effective f# then the
DOF in the photograph made with the teleconverter will be DOF of 50mm lens
divided by converter strength squared. Thus a 50mm lens operating at f:8 might
have a DOF of 16 feet and when you insert a 2x converter making it a 100mm and
open up to f4 (effectively making it a f:8 100mm lens) then the lens will
exhibit a DOF of 16/4 or 4 feet.
If you stop the 50mm lens down to f:16 then since DOF is directly proportional
to f# the DOF will be twice as large at f:16 as at f:8. If you switch to a 100
mm lens and use it at f:16 then DOF will be 1/4 that of a 50mm lens used at
f:16. Ultimately this means that if you use the 50mm lens at an effective
aperture of f:8 and the 50mm plus 2x converter at f:16, then the lens with the
2x converter will exhibit a DOF which is 1/2 that of the 50mm lens. If you
adjust the size of the image made by the 100mm lens to match the size of the
image made by the 50mm lens then the DOF of the two images will be the same.
So, as long as you do not change the f# setting on your 50mm lens but insert a
2x converter behind it, the new DOF will be 1/converter strength of the old
DOF. If you enlarge the 50mm neg to match the image size produced with the 50
+ 2x converter the DOF will be the same.
-anonymous ================================================================================
Note 34.15
-< Title slides with BLUE backgrounds - how to make them? >------------------------------------------------------------------------------->I want to do slides with blue background and text on white. Note: I don't
>want to use a computer.
Here are 3 methods:
A
use slide film (100 ISO) to make a copy of your originals through a
yellow filter and then use C41 processing. All chrome films don't give
file:///C|/faq.html (365 of 555) [7/19/2002 3:46:30 AM]
B
C
same blue (FUJI was good) Try differents exposures.
lith film, lith developper (to generate a high contrast bw negative)
use blue DIAZO film with UV light and process in vapors of amonia
(diazo film can be found in most graphic arts shops)
Polaroid Polablue
- diazo need UV light and ammoniac process (problem with vapors) it is very
inexpensive and most applicable for BIG production.
- Polablue is very expensive (and need a processor)
- Slide film + C41 process is a good way for small production.
Now I use computer !
Pascal MIELE, [email protected]
.............................................................................
The easiest way to do this, blue background and white letters, follows. Prepare
your text and graphs as black type on white paper, a laser printer works great.
Get a roll of slide film, the cheapest works great, and photograph the text and
graphs you need using a YELLOW filter (Y2 works great); you can even use
regular tungsten bulbs. Once you have finished, take the film to the lab and
instruct them to cross process it (develop it in C-41 chemistry). Usually cross
processing is cheaper than regular E-6, at least around here (Mexico City).
That is all there is to it.
Is there any need to state that you can get a green background and white
letters, red or magenta background and white letters, etc., etc., etc. Use your
imagination and your filters.
Francisco Garcia Maceda, [email protected]
...............................................................................
The process is reverse text slides. The best way is to use Kodak Vericolor film
5072, SO-279 which is used to produce slides from color negatives. This film is
a clear base negative film C41 process.
Cat NO 122 1217
cat No 162 2364
for the 30.5 meter bulk
for rolls of 135-36
By printing out type on white paper from a word processor by laser or ink jet
printers you have to copy this on the above film with yellow filters. Simply
the black type goes white and the white background made blue. By using tungsten
lamps 3200k and a filter kodak wratten gelatin filters number 15 and 106 (amber)
and exposure at 6 ASA off a 18% grey card (my exposure is f8 for 2 sec this is
a slow tungsten film and must be exposed as such) copy your materials then you
pop down the street and put the film through the 1 hour C41 and 'hey presto'
reverse text slides. When you buy the film the instructions are in the box and
you may change the background colors by filters, they list 9 in total. I make
lots of these slides and people just give me books or their printout from the
work and I copy them with the above setup.
Note 35.01
-< Where to get phjoto jigsaw puzzles made >------------------------------------------------------------------------------->Where can I have my photographs made into jigsaw puzzles?
Photo jigsaw puzzles can be obtained at Fox Photo and CPI Photo stores.
Check out the Fox Photo/CPI Photo home page at http://www.cpiphoto.com or
e-mail back to me for further information.
file:///C|/faq.html (366 of 555) [7/19/2002 3:46:30 AM]
[email protected]
...............................................................................
I have always been a puzzle nut and about 25 years ago I decided that my three
children needed a college fund so I put my enthusiasm about puzzles into a new
business venture. Currently we manufacture photo jigsaw puzzles for some of
the major wholesale photofinishers who have accounts in K-Mart, Walgreens, etc.
I find that there is a vast number of photo enthusiasts (and others) who would
like a one of a kind custom jigsaw puzzle but do not know where to get one. I
have decided (with my family) to go on the net and provide a very unique, one
of a kind, service. Our site (under construction) "Jigsaws to Order" will
convert any photo, drawing, in fact anything printed on paper, to a superb
quality, fully interlocking jigsaw puzzle. The original would be returned as
pieces of the actual jigsaw puzzle.
Marcia Joslin
P.S. We are a long time member of PMA.
Joslin Photo Puzzle Co., P.O. Box 914, Southampton, Pa 18966-0914 USA
E-Mail [email protected] , Voice (215) 357-8346, Fax (215) 357-0307
================================================================================
Note 35.02
-< What to do with a camera that took a dip in the sea? >------------------------------------------------------------------------------->I have a Canon EOS 100QD which I had an accident with. That is, I got it soaked
>with salt water!! and it is not responding in any way. Is there anything that
>I should do immediately to try to salvage it?
Alas you probably have an expensive paperweight on your hands considering the
likely amount of time that has passed since it happened and now when I read
your post. The problem is that sea water is a conductive electrolyte zapping
out and corroding out the electronics with all the spurious connections it
makes. The only-hope-first-aid when something like this happens is
_immediately_ turn it off and get the batteries out of it, and rinse it in
multiple changes of distilled water with a bit of soak time in the latter
rinses. The next step is to dry it out. One school of thought is to do a final
rinse in isopropyl alcohol which mixes with and greatly dilutes the water left,
but evaporates much more readily. Others claim that alcohol will attack and
dissolve plastics. I doubt it. Either way you have to dry it out--a hair dryer
on a moderate setting gets it started. Then keep it in a warm dry place for a
few days--maybe a cardboard box with a light bulb. During this time spin the
prayer wheels to the photo- graphy gods. Finally when you are sure it is dry,
put in new batteries and turn it on. Good luck.
Mike, Michael McGuire Hewlett Packard Laboratories
Internet: [email protected]
================================================================================
Note 35.03
-< Russion Horizon(t) rotating lens panoramic cameras >------------------------------------------------------------------------------->What are the differences between 1970 and 1990 Russion Horizon(t) pnaoramic
>cameras?
file:///C|/faq.html (367 of 555) [7/19/2002 3:46:30 AM]
I have both 1970 and 1990 models. The old model has a single rotation speed
(1/30 @ full slit width). There is also a 1/60 and 1/125. Early (1967)
versions also had a 1/250 marked but because the slit width was so narrow
there were eneven exposure problems. The next versions (1971) removed the
1/250 marking but the detent setting was still present and can be used.
There seems to be an optimum optical slit width which is why Widelux and
Noblex use a fixed width.
The latest Horizon 202 has two rotation speeds and carries over the design
provision for four slit widths with only three marked (hence the unmarked
setting you referred to) and only three. The new rotation speeds are 1/60
and 1/2 while the slit widths are the same as the 1/30-60-125 of the old
model. This way they can offer a 1/250 which has even exposure.
The Widelux by the way uses three different governors to alter the rotation
speed and the slowest and fastest are often problematic.
I think of the FT2 more as a collectors item with limited usefullness as a
user camera.
-ANDREW VAN DIS, [email protected]
================================================================================
Note 35.04 -< How to expose, process and use Kodak Pro Copy film 4125 >------------------------------------------------------------------------------->I'm finally getting to a project for which I bought a box of #4125 film some
>time ago. 'Course, the first thing I did was take out the data sheet to read.
>The next thing I did was lose it. So any info on this product (e.i. rating,
>lighting sources, developers, processing times) would be greatly appreciated.
here's some info on your film .... ISO = 12
with tungsten light source
Contrast is controlled by both exposure and development. The mid/dark tones are
controlled by development whilst the high lights are controlled by the
exposure. The data file is a little vague on developing basically saying it's a
matter of some experimentation and taking into account the original. ie if the
original has faded you might want to increase the exposure half a stop or so.
However here's the basic info:
Safe light = dark red No2 with 15 watt lamp
HC-110 dil.E (tray)
4min
at 20C (68F)
(rack/tank)
5min
at 20C (68F)
DK-50 (1:1) (tray)
3min
at 20C (68F)
(rack/tank)
3min 30s at 20C (68F)
Stop bath.
10sec
at 18C (65F)
Fix.
5-10min
(or Kodak Rapid fix
2-4 min)
Wash for 20-30 min in running water @ 18-22C (65-70F)
For a diffused light source enlarger the neg should have a D-Max of 1.20
FYI the film has now been replaced with Kodak Gravure Positive film 4135 (ISO 8)
I think the problem with Kodak is it's vast size makes it inefficient, although
I've found the UK technical support very good on the phone and fax. I agree
with Robert Chebby putting technical info on the Net would be ideal, exactly
what it should be used for!
Steve Tristram <[email protected]>
file:///C|/faq.html (368 of 555) [7/19/2002 3:46:31 AM]
...............................................................................
Pro copy film:
Tungsten
ISO 12/12
Pulsed-Xenon ISO 25/15
Exposure:
Tungsten: 2 500 watt reflector or 3200 K lamps, 36 in from center of copy
f/22 8sec no filter
Pulsed-Xenon: 2 1500 watt lamps, 36 in from copy center
f/ 32 8sec no filter
Dev 68F (20C) with agitation
tray (continuous agitation), tank (agitate at 1 min intervals)
Tungsten:
HC110 Dilution E
4 min
5 min
DK-50 (1:1)
3 to 3.5min
3.5min
Pulsed X:
same
this info is from a
sheet is dated 2/89.
I use the HC110 at 5.5 min. agitating every other half min as well as every min
the voice of Kodak (the 800 number) is generally very helpful if you don't mind
wandering through the automated answering machine and waiting for a live voice.
I can send you a fax of the data sheet if you'd like.
L. Vanderploeg, [email protected], U. of Wisconsin-Madison Media Lab
...............................................................................
I don't have the data sheet but try Kodak's web page
http://www.kodak.com
Rich Lubitz ([email protected])
................................................................................
I use this quite a bit.... Set film speed to 12
Process in HC 110 Dilution E (that's 1:47 from the *syrup*)
Tank processing in Film Hangers ...5.5 min. At 68 deg F/ 20 deg C
You can expose up to about 10 seconds before reciprocity failure cuts in. Since
the film is orthochromatic you may process in red safelight conditions and
develop *by inspection*
Ken, [email protected]
................................................................................
Info on Kodak Pro Copy 4125: ASA 12 with tungsten or quartz-iodine lighting
HC-110 (dilution E) - 6 minutes in a tank @ 20 C or
DK-50 (1:1) or similar developer - 8 minutes in a tank @ 20 C.
These are good starting points for exposure & developing times. With this
film, added exposure increases contrast, and reduced exposure reduces contrast.
Use this for adjusting your results. (Film is designed this way.) If you have
a densitometer available adjust exposure to produce a highlight aim density
of 1.52.
Dave Van Verst, Morton Professional Photo Lab, Morton, IL 61550
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[email protected]
..............................................................................
Kodak Professional Copy Film 4125 (Estar Thick Base)
Orthochromatic film retaining highlight graduation in copies.
*Moderate course grain
*Medium resolving power
*Provides increased highlight contrast needed for continuous-tone copy and
in photogravure reproduction
*For use with Kodak Safelight Filter No.2 (dark red) or equivalent.
*Film Speed: Tungsten and QuartzIodine, ISO 12/12, Pulsed Xenon ISO 25/15;
White-Flame Arc,ISO 25/15
*Recommended Kodak Developers HC-110, DK-50(1:1)
The only reference for I have for development times is:
8 minutes at 68F/20C degrees in HC110 1+7
From: [email protected] (LW)
================================================================================
Note 35.05
-< Photo Contest Tips >-------------------------------------------------------------------------------Tips for Winning Photo Contests
Excerpted with permission from "Contests, Grants and Awards for Photographers"
edited by Richard S. McWherter, Walkwood Publishing Company
Copyright (c) 1995. All rights reserved.
(See information at the end of this article.)
1.) Edit your work before submitting it for juried contests. Be brutal. Don't
include the same subject in more than one picture unless it is part of a work
in series and will be judged that way. As a photographer, you are always
editing. Deciding what not to include in your viewfinder is just as important
(some would say more important), than deciding what to include. Use the same
knowledge and instinct that you use in making photographs when you are editing
your work.
2.) Submit only your best work. There are several ways that can help you decide
which is your best work. In most cases, you already know, but you may lack
confidence about your work. In those cases, seeking the opinion of others may
be helpful. Try to find people you respect and will be honest with you.
Ideally, it might be someone in photography or the arts. Be careful, sometimes
the picture that is the most popular among your friends and family may not be
so unique to judges or people who work with images.
On the other hand, you may be over confident about your work, especially if you
attach emotions regarding your memory about where you were and how you made the
photo. In this case, it's sometimes a good idea to put the work out of sight
for a while and then return to it later with a more objective eye.
Other suggestions that might be helpful would be to learn as much as you can
about composition and design. One hint is to view your picture through a
mirror, or even upside down. If you have an understanding of composition, then
you know that a good composition is usually good no matter how you look at it.
If it still looks like a good photo backwards or upside down, then it probably
is. If not, move on.
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3.) Images should be properly focused. Proper focus does not mean everything
must be in sharp focus. However, a good image that is obviously out of focus
will fail. In fact, what determines a great photograph from a good photo is
what the photographer decided should be and should not be in focus. Even in
abstract or blur motion images, there is usually at least one element of
critical focus, even if that element is simply the grain structure of the film!
4.) Proper Exposure. Proper exposure in the classical sense is an image that
has details in both the highlights (white or light areas) and shadow (black or
dark areas), with a generous range of shades in between. However, this area is
more open to interpretation in contemporary work. In fact, some photographers
over or under expose to achieve certain effects. An example might be an image
where the highlights go off the film scale and can give an image added
emphasis, particularly if it is an environmental portrait in a harsh locale. In
this case the contrast exceeds the limitations of the film, but it might be the
best interpretation for that photographer. However, for most work, films that
are properly exposed and have a normal contrast range are the best bet. If
you're unsure about the proper exposure, take comfort knowing that even many
professionals bracket their exposures to make sure they're covered.
5.) Always ask for details directly from the contest organizer regarding the
type of contest, the scope (national, regional, etc.), the eligibility
requirements, the subject or theme of the contest (if any), the entry fee and
the awards. A stamped, self addressed reply envelope works best to request
entry details or forms. The book "Contests, Grants and Awards for
Photographers" (see below) is a good starting point as a source for contest
listings. One item to look for is the ratio between the amount of the entry fee
and the prizes awarded.
6.) Other items that should be of interest to you are the rights and ownership
of winning entries. I would never enter a contest that takes away all of the
photographer's rights, regardless of the prize. Most reasonable people would
consider this exploiting photographers. And I am very particular about what
organizations request in rights. In most cases it is reasonable that
organizations request rights to use your images to promote the contest itself.
However, it becomes a little less clear if companies use your pictures to
promote their products without further compensation to you. In all cases, those
rights should be limited, particularly by the time frame that the rights are
granted.
7.) Colour or black and white? This one is more difficult, since colour is such
a strong part of our culture. Some contests have separate categories to address
this problem. In a lot of cases colour work gets more of the glory. However,
one way to stand out in a sea of excellent colour images is with a very
powerful black and white photograph. Sometimes we see so much colour daily,
that when a dramatic black and white comes along it can stop us in our tracks.
My personal approach is I use colour work for landscapes; where colour is part
of the experience of remembering or creating a time and place. In comparison, I
use black and white images for portraiture. Black and white images are great
equalizers, the camera doesn't care how nice your clothes are or what colour
your skin is. What counts in a black and white portrait is the expression of
both the subject and the photographer. The mood and the essence of the person
become paramount and black and white can remove the distracting emotions that
overwhelming colours can create.
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8.) Presentation is 9 tenths of the law. How you present your work is very
important. But that doesn't mean you should buy expensive folios or cases.
Excesses on both sides of this scale can be harmful. Judges are not impressed
by how much you spend on your presentation and are often annoyed by cumbersome
mats, frames or folios. On the other side, the care and handling of a fine
print presentation is often seen as a carry over from the photographer's
attention to detail and that can be influential. And of course, scratched and
dirty prints that are not spotted and have bent corners only distract from your
work. In all cases, you must follow the specific guidelines published for each
contest you're interested in. Some allow mats and frames, some don't. And those
that do usually have detailed instructions regarding sizes, etc.
9.) Often contests ask for you to submit slides of your work, even if the
original is a print. In these cases, you must copy your work with 35mm slide
film and submit the copy slide. Colour slide film with a low ISO speed usually
works the best. Ektachrome, Fujichrome or equivalent are fine. Kodachrome may
give you a slightly better slide, but it is usually more expensive to buy and
process and can take awhile longer at the lab. The Ektachrome films are fine,
especially since there's a chance the slides might not be returned or could be
damaged in shipping.
Use daylight balanced film for flash or tungsten film for photofloods. Use a
tripod and a cable release and lock the mirror for the sharpest image. A copy
stand is highly recommended. Bracketing your exposures is helpful, but don't
over do it. A written record of your copy exposures will go a long way when you
need to repeat the process. Remember, this is the only example the judges will
have of your work, so it must be the highest quality copy possible and
faithfully represent your work.
If your original is a slide to begin with, send only a duplicate slide.
Duplicates can be made by most labs or you can make them yourself with the
right equipment. If your subject permits, the least expensive extra slide can
be made at the same time as the original by shooting extra frames. In all
cases, never send one of a kind originals, unless you don't mind never seeing
them again.
10.) The heart has its reasons, which reason can not know. This last tip is
probably the most important. Basically it means that you must make photographs
that you are passionate about. These are the photographs that win most
contests. You should not try to reason which pictures will win a contest (or
have won) and then try to photograph those kinds of pictures. However, if you
continue to make photographs that are important or pleasing to you, you will
become better at it.
Never make photographs because you think you'll make money winning contests.
It's not about money. It's about making photographs because nothing else
matters unless you do. If someone else appreciates your work, then that's just
icing on the cake.
As a final note, let me remind you that persistence is the key to survival. If
you enter contests regularly, you must get use to rejection notices like a duck
is use to water. I enjoy the recognition that contests have brought me, but I
have never let a critic or a rejection slip stop me from what I know is right
for me. Don't let it stop you! Good Luck!
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Rick, [email protected]
__________________________________________
Permission to reprint or repost this information is granted to the reader
providing the following conditions are met: The file title, author's name and
the copyright notice must remain in place along with the author's short
biography and the name and contact information of the publisher.
_________________________________________
Richard S. McWherter is an artist working in the medium of fine art
photography. For more than eighteen years his activities have included the
learning, creating, exhibiting and teaching of photography as a Visual Art. His
work has appeared in many regional shows and national exhibitions. He has won
numerous awards and his photographs have been published in national magazines
for fine art photography. He continues to promote the art of photography by
exchanging views and resources with students, artists, photographers and
enthusiasts.
_________________________________________
For more information on photo contests, including details of the author's newly
published book with a comprehensive listing of opportunities for photographers,
note that "Contests, Grants and Awards for Photographers" has over 200 sources
of contests especially for photographers with award totals over $100,000.
Please contact the author via Compuserve (73071,1112) or the internet
([email protected]) or the publisher below for complete information.
Walkwood Publishing Company Box 246 Derry, PA 15627 USA
================================================================================
Note 35.06
-< Restoring faded photos by copying >------------------------------------------------------------------------------->A client has asked me to "restore" some old photos. They're extremely faded,
>and have a yellowish cast to them. Seems to me I remember that copying with
>a yellow filter does a lot to bring out some contrast & detail. Any help on
>this project from you experts out there will, as always, be deeply
>appreciated.>
If they're very faded just copying them won't work very well. You need to
increase the density in the actual photos. There a very clear step-by-step
description on photo restoration (not just copying) using a silver nitrate
formula in the Time-Life book, Caring for Photographs. Not cheap though.
George Struk / [email protected]
...............................................................................
Kodak has a pamphlet out about this, probably available free if you call
1-800-242-2424. The production of a clean, new duplicate of the photo can be
done with ordinary short-toed panchromatic sheet film and commonly available
filters. Typically, the image's black "density" has been converted, by means
of a combination of leftover fixer in the film and atmospheric sulfur compounds
into silver sulfide. The density is still THERE, only it's in the form of
yellowish silver sulfide.
Using a sheet film like T-Max 100 or Plus-X (or rollfilm if necessary),
photograph the faded print through light and dark green, and blue filters, over
a range of exposures. A correct mix of filter and exposure will yield, in many
cases, a negative which will make an excellent new copy print, with most if not
all of the fading corrected. What you have done is to limit the light
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available at the negative to colors which are blocked by the yellowed silver
sulfide. In blue light, that thin yellow deposit appears to be opaque, just as
black silver deposits appear in white light!
It works; I've done it. If the original image has other problems, then
electronic restoration may well be necessary, but for simple fading, it is
often just as easy to make a negative and copy print this way.
Edward M. Lukacs, LRPS, [email protected]
================================================================================
Note 35.07 -< Poop sheet on processing outdated Agfa Superpan Press >-------------------------------------------------------------------------------> ...I recently picked up 5 bricks of some outdated B & W film at a photo flea
> market - Agfa Superpan, ASA 200... anyone have handling/processing pointers?
Agfa Superpan was imported "gray market" during one of Agfa's many changes of
distributors. The time frame was 1981 I woiuld guess.
I contacted Agfa at
the time and received a reply from the Gevaert graphic arts group in New York
City, supplying development info and advising me that this was an unauthorized
import. By the time I got the response, I was convinced that the film was the
best that I had ever seen with finer grain than Plus-X, and more latitude. I
even ran some tests and found it made nice negatives when developed in Diafine
with an EI of 500 or 640! Wrote back to the guys at Gevaert and asked WHY they
weren't importing the best film they made!
Reading from the data sheet that they sent me (Still have it!
for more!) ypu can use the following at 20C (68 deg. F):
Rodinal
Rodinal
HC-110
HC-110
D-76
Microdol-X
Microphen
ID-11
Neofin Red
1:25
1:50
1:15
1:31
Straight
"
"
"
"
6
10
4
11
6
8
7
7
17
Still waiting
minutes
minutes
Minutes
minutes
Minutes
minutes
minutes
Minutes
Minutes
With some benzotriazole, that Superpan might be useable, as since it was still
in a brick, it might have been kept cold. I'm not kidding, it's great!
Edward M. Lukacs, LRPS, [email protected], Miami, Florida, USA
================================================================================
Note 35.08
-< T-mounts, what are they? >------------------------------------------------------------------------------->What is T mount and T* mount? Is Contax/Yashica mount the same as a T mount?
T mount is an attempt to be able to utilize one lens for SLRs of different
manufacturers. The lens itself had on the camera body side a standard T mount
male thread. The T mount adapter - one for each different camera mount - was
between the lens and the camera body. This adapter had on the lens side a
female thread to fit onto the male thread of the lens; on the camera side of
the adapter was the standard body coupling for a given camera. So you had an
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adapter for Nikon, one for Olympus, one for Minolta, etc. This allowed you to
use the same lens with different camera bodies...all you needed to do was
acquire the respective T mount adapters.
Needless to say, such lenses are not automatic; that is, they did not allow
you to focus at the largest f/stop and - when the shutter release was
depressed - 'automatically' stop down to the selected f/stop and then open up
again to the largest f/stop. Instead, they are pre-set: you set the lens at
the f/stop you wanted with one diaphram ring, turned the lens wide open with a
second diaphram ring, focused, then - just before you hit the shutter release
- stopped the lens down to the desired f/stop by turning that second diaphram
ring until it came to rest against where the first diaphram ring was set. Slow
and cumbersome and easy to overexpose because you forgot to stop the lens down
again to the taking f/stop. But the system worked and rather inexpensively at
that.
Lawrence Akutagawa, [email protected]
..............................................................................
A "T" mount as in Tamron is a system that makes a accessory lens with
a screw mount similar to the M42 (Pentax/Pratika) it has a coarser thread
pitch. You would then screw on your Nikon, Pentax, Minolta etc adapter to
mount this lens to your camera. You will still see T-mounts on microscope
and telescope adapters, plus some mirror lenses. Tamron developed the T
mount system but dropped it in favour of their Adaptall mount, as the T
mount did not allow for meter coupling so most T-mount lenses were of the
`pre-set' aperture type. A few companies tried to improve on the T-mount
(such as the TX mount) but these were clumsy attempts at best. Only Tamron
stuck with the interchangable lens mount concept (for manual focus cameras)
all the other Aftermarket lenses went to a fixed mount.
From: [email protected] (Darrell A. Larose)
================================================================================
Note 35.09
-< Photography - the 8th art - article by Robert Fournier >-------------------------------------------------------------------------------PHOTOGRAPHY: THE 8th ART (as seen on the PhotoHst mailing list)
Copyright: Robert Fournier, 1995
"The arts equally have distinct departments, and unless photography has its own
possibilities of expression, separate from those of the other arts, it is
merely a process, not an art; but granted that it is an art, reliance should
be placed unreservedly upon those possibilities, that they may be made to yield
the fullest results" (Alfred Stieglitz, 1901 - from Alfred Stieglitz:
photographs & writings, National Gallery of Art, Callaway Editions 1983)
It is through the study of the mechanics and chemistry of photography, by
questioning inherent characteristics, unique to the process, and by comparison
of photographic expression with that of other art forms in which an artist can
express himself through is medium. It is by understanding what photography is
and does that one comprehend the "idea of photography".
From my artistic practice, I have identified an pattern in most forms of
artistic expression. Fundamentally, art is a form of communication as well as a
way of expressing oneself or one's visions and emotions to others. There is
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always a message to communicate in an artwork and this message is the idea that
the artist wants to express. Actually, I am talking here about the act of
creation and not of interpretation.
The dictionary defines an idea as a abstract representation of a person, an
object, a relation... elaborated by the mind. In any case, an idea is an
abstract phenomenon, a quality considered as its own entity, independent of the
object of which it is an element. It is in the imagination that the idea takes
a shape. This is where painters see images and musicians hear music. It is his
imagination, inspired by an idea, that guides the artist into the realization
of his artwork. The idea is then the activating part of imagination, which is
realized with the personal vision of the artist, with the goal of
interpretation. From this point of view, I believe that most art forms follow
this pattern: IDEA - IMAGINATION - ARTWORK. Photography that end with the
realization of an image, should be one of these art forms using the
two-dimensional space as a mean of expression. It would then be just another
technique within this art form.
Like artists of other disciplines, photographers can imagine an infinity of
images from their mind and memory, but they will not be able to produce
anything without a concrete objects to photograph. Painters can remember the
shapes and colors of an apple to draw an apple; or likewise writers to describe
one. Photographers need the apple to make a picture of it. They cannot avoid
their environment, and the image formed by the lens is determinant.
The necessity of an object establishes a kind of relation, a direct bond
between the photographer and the reality. It is precisely on this relation that
"the idea of photography" is founded. Two different avenues are frequently
taken in the artistic approach of photographers. The firs one involves in
reassembling and arranging elements needed to realize their idea, then
photographing it. For example, practitioners of plastic art who use photography
to produce their artwork. This approach coincides well with the preceding
pattern: IDEA - IMAGINATION -ARTWORK. Their interest is mainly pictorial and
their approach is similar to that of artists whose expression is in image
making.
The second approach is founded on the acceptance of all elements needed for
realization of an image, just as they are and disposes in their actual
environment. Qualified as "straight photography", the subject has major
importance for the practitioners of this approach. Images so produced are, in
other words, recreations of real events. Many of these photographers, preferring
objectivity to interpretation of the event they are witnessing, abstain from
interpreting during printing as well. Other allow a certain subjectivity with
minor manipulations. But in either case, these photographers show a profound
respect for the truth and reality of the subjects they are photographing. This
second approach differs from the former pattern in that there is the necessity
of a relationship with actual reality. The idea, then, is suggested by the
environment in active evolution. I would describe this new pattern as:
REALITY - IDEA - IMAGINATION - ARTWORK.
The actual study of photography, as any other visual art, is usually studying
the artwork. According to the preceding pattern, the fundamental difference of
photography is in the relation between the idea and the reality and not in the
artwork. Difference happening here are mainly technical and proper to the
photographic material. It is not because an artist is using material belonging to
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photography that his approach responds to "the idea of photography". This
approach differs from pictorialism principally, in the degree and quality of
attachment with life and the insistence on truth in representation. It never
abolishes the plastic aspect of the medium, it only establish new frontiers and
gives another direction. The esthetic is now devoted to life and reality. What
is the foal of one, is the means used by the other to reach his goal.
"The idea of photography" comes from the concept of equivalence first stated by
Stieglitz in the twenties. It was then adopted by many photographers,
particularly by Minor White. This concept is based on the fact that we are
impressionable and we react to visual events. At this moment, an emotional
equivalent is defined, this is where the idea of equivalence occurs. It
represents impressions felt and lived. Whether the approach is documentary or
pictorial, objective or interpretative, the motive of expressive photography
rests in this equivalence, establishing the relation needed between the artist
and his subject. Equivalence does not have any style, nor does it belong to any
specific art form; it is an impression, a pure emotion.
So far "the idea of photography" rests in the relation of the artist with
actual and living reality. Images produced by him result from his intimacy with
life and reality. It is a noticeable fact that many of these photographers
devote a real passion and a profound respect to their subject matter, often
beyond the appection they devote to the work they produce from it. This
particular relation with the subject resides in the capacity to look
differently through the viewer of the camera. Produced images show the relation
between the artist's imagination and his environment in actual evolution,
whether he decides to interpret it or not.
The photographer must feel reality and the subject within himself, and it is
the equivalence that permits him to do so. Otherwise the subject has only an
interpretative value. The profound bond and the sensation of belonging that
come with the spontaneity of discovery is not there.
From its relationship with reality, photographic images relieve very often,
from historical document. The spontaneity of the medium and his impressive
capacity of reproduction may make the viewer forget that a photograph is also a
representation of the reality perceived by an artist. Reality is both, inner
and outer to the human being.
Another particularity, coming from the camera, is the integrity of the image
that it reproduces. Any artist from another discipline, that lets himself being
stimulated by the actual environment and attempt to interpret it, as poets and
painters for example, can not profit from this particularly. Because of the
slowness of execution of their medium compared to the spontaneity of the
camera, the events in progress will change. Also, human being see what they
want to see. What is perceived from reality is slanted by numerous
psychological factors from the subconscious. The camera, on the other hand,
record everything, including what one doesn't see, with an absolute
objectivity. Symbolic analyses of repetitive elements found in the work of a
photographer reveal new dimensions of the subconscious that could remain
unnoticed through other media.
Concern for care of truth and respect of reality gives to "the idea of
photography", its own possibilities of expression, separate from that of other
art. This way of thinking is noticeable in the work of photographers, such as
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Henri Cartier-Bresson, Edward Weston, Ansel Adams, Arnold Newman, Robert Frank
or Richard Misrach,; to name just a few of the best known.
Is it possible, under the light of these reflections, to pursue the
understanding and to judge photograph, solely by the study of the photographic
image, without consideration of the artist's experiences with reality ? The
photographer expresses himself through reality and the photograph is the
reproduction of this reality that is stimulating him. Photography is the art of
reality and it is through this connection with the artist that one will
understand the message transcending a photographic image.
Robert
Fournier, <[email protected]>
================================================================================
Note 35.10
-< Developing stacks of prints simultaneously >------------------------------------------------------------------------------->Does anyone have experience in developing groups of prints together. Obviously
>stacking prints in the developer slows development, but by how much? Does the
>extended development time outweigh the benefits of developing them all
>together? Is the job of rotating the stack a real pain? I can imagine it being
>difficult to get a nice steady rotation and even development if they start
>sticking together.
A number of years back we used to routinely soup 8x10's this way in the
Air Force, and I have done it a number of times since. At times I could
handle 12 to 15 with no noticeable difference with any done separately.
A few points:
1. The test strip or print MUST be fully developed. Don't pull it when
it looks right and run the rest. Dev at least 2 minutes in trays
that are at least the next print size larger, i.e., 11x14 for 8x10's.
2. Expose for about 5 to 10% LESS for the stacked prints. Seems weird,
but that's the way it works.
3. Take ALL of the prints off of the easel and stack them to the side in
exactly the same way, EXCEPT the last one, which you will turn around.
4. Then fan the prints out, like you would if you were going to make up
a bunch of tests out of separate stacks. This will make them much
easier to grab.
5. If you're right handed and work from left to right, you will need a
dry area to the left of the dev tray where you can lay the stacked
prints face down.
How:
6.
7.
Pick up the top print with your left hand and lay it in the dev tray
EMULSION DOWN. Note: Do NOT get developer on your left hand yet.
Push it "gently" down with your RIGHT HAND so it's completely
submerged in the soup, jiggling your hand from side to side a little
as you do it. At the same time, with your dry *left* hand, pick up
another one and lay it in the tray, again face down. Continue until
they are all in the tray.
Put your left hand in the tray, getting it wet with developer,
and GENTLY pick up the stack just enough to turn them over (this
keeps most of the soup between the prints so they won't tend to
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stick as much), and start taking them separately from the bottom and
putting them on top, submerging them as you go. Keep the same
rhythm that you used when you put them in the tray and development
should be very even.
8. The inverted (or upside down picture-wise) print will be the first
one in, so it should be the first out. Remember, you flipped the
stack after putting them all in, so you want to remove the top one
first. With your left hand, remove the top print from the dev and
lay it, emulsion down again, in the stop or water tray, pushing down
again with your right hand. Keep taking the top prints from the dev
with your left hand and laying them in the stop or water trays, and
then, with both hands wet with stop bath or water, gently turn the
stack over again.
9. While keeping the whole stack submerged, remove them from the stop
bath tray one by one, with your left hand, from the top (as in #8)
and put them in the fixer tray, submerging them again with the right
hand. You will have to agitate them some in the fixer. Don't just
let them sit, or they won't get complete fixing.
Note: If you don't squeeze the whole stack of prints when they are in
a solution, there will be enough fluid between them to prevent their
sticking together. Lay them in the fixer loose, and you should be able
to just sort of fan them out a couple times to help circulate fixer.
Also go through them a couple times like you did in the developer.
Sounds complicated, but I tried to cover a couple detail points, like not
grabbing dry prints with wet hands, or putting the stop bath hand in the
developer tray. For practice, try a stack of dry prints in dry trays
until you get the routine down better. If you do it like I explained,
prints sticking together shouldn't be a problem, and you'll soon be able
to do one a second into the developer, and keep that pace from that point
on.
Have fun. Just be sure of the exposures. Having 10 prints all too light
or too dark is very aggravating.
John Thompson, Canton, Ohio <[email protected]>
.............................................................................
> ... I've just finished reading AAs book The Print, in which he mentions using
> the factorial system for determining the development time for a number of
> prints stacked in the developer at the same time. Ie. the ratio of the
> emergence time to full development time is constant for a given developer,
> paper, temp etc etc ... Thus knowing this ratio (or factor) you can apply
> it to the first of a stack of prints and find the full developing time
> for that stack.
I have tried to use AA's factorial method, but have found that it is very
difficult to compute for each print or batch. Visual inspection seems to
work better. Most important is keeping the developer a constant temp. (I
use an immersible aquarium heater in a water bath set to 68, or whatever).
Make sure you have plenty of liquid in the tray for the session.
As far as processing prints in batches, I usually develop in groups of 2, 4, 6
or sometimes 8. More than this and you can't give enough attention to each
print. I may expose a bunch, say 10 or 12 at once, but process them in two or
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three groups. It is important to get them in the tray quickly--one after
another--then start your timer. Dilute your developer so your total
development time is 2 1/2 -3 minutes, that way 5 or 10 seconds between the
first and second print is not much of a factor. Put the prints in face down,
push the print down slightly with one hand and rock the tray to cover the back
of the print with developer (try to keep your hands dry at this point), and
put the next one in the same way. When you have all the prints in, go through
the stack once, pulling the bottom print and turning it over on the top of the
stack. Next, turn every other one over so that each group of two is back to
back. Now you only need to rotate half as many items, treating each back to
back group of two as one print. My experience shows that, although it may seem
that more prints=more development time, when you consider the extra agitation
each one gets, one must be careful not to OVER develop the prints!
Back to back prints will stick together, but that actually helps you in this
case. The emulsion sides repel one another. When development is complete
quickly move each stack of two to the stop bath. seperate each stack so the
stop can get between each stack briefly. Move these groups of two into the
fix and go through the pile a couple of times. Separate each group of two so
the fixer can go between the two and replace any stop trapped between them.
This all may sound complicated, but once you get the feel for it, it
really does save a great deal of time.
Don Duncan, [email protected]
...............................................................................
Years ago, in another life, I worked as a darkroom assistant in a portrait
studio. My main purpose on the job was to turn (or "page") the prints in the
fixer, after the photographer had developed them in stacks and moved them into
the short stop.
I would say you could easily stack half a dozen prints. It helps to use trays
which are larger than you might normally use for single prints of the same
size, and with generous amounts of chemistry in each tray.
I used to put the exposed, dry prints in the developer tray one at a time,
quickly adding the additional prints one at a time. You will work out a rhythm
for this which permits you to "know" how much time there was between prints.
Once the prints are wet, they are less likely to stick together than when they
first go into the tray (which is why I don't put the whole stack in as a
group).
You may see some unevenness in the initial development, but full developing
time will take care of it.
The bottom print is
Proceed through the
down. Now move that
keep track of where
brought to the top of the stack, and turned face down.
stack until you reach the print on the bottom which is face
print to the top of the stack, face up. This permits you to
you are in the stack.
When the first print has received full development, you can begin transferring
prints to the short stop, using the time interval between prints which matches
the insertion time.
file:///C|/faq.html (380 of 555) [7/19/2002 3:46:31 AM]
~NORM, Norman Lenburg <[email protected]>
================================================================================
Note 35.11
-< Quick and easy "X" sync flash test for field use >-------------------------------------------------------------------------------> How can you easily and cheply tell if your electronic flash fires at the
> correct "X" synchronization?
Take a piece if phosphorescent glowing tape (sold at theatrical supply houses
or through the Set Shop in NYC) and fill a 3x5 card with the light sensitive
tape. Then, with the camera back off or open hold the taped paper against the
shutter gate on the film path. (Don't press too hard or you will interfere
with the shutter when it fires)
Set your shutter speed to the highest that your camera will synch. (1/125
or 1/250 or whatever). Now point the camera without a lens towards the flash
and fire.
Quickly look at the card. The full rectangle of the film gate should be
glowing on the card. If it is a narrow rectangle then you are not synching
properly. This is a wonderful field trick and it really works.
[email protected] (Gary Gladstone)
================================================================================
Note 35.12
-< How to compensate for exposure using extension tubes >------------------------------------------------------------------------------->I just bought a set of extension tubes for my medium format camera. The short
>tube requires an exposure adjustment of 2X, the longer one 3X. In terms of
>exposure steps ie full f-stops OR shutter speeds, can someone explain to me how
>to adjust the exposure for each tube and when the tubes are used together. The
>camera has no internal meter, so everything has to be measured with a hand
>held meter.
If the exposure increase is indicated as an exposure FACTOR, then 2X
translates into increasing lens f-stop by one stop (doubling the amount of
light), or decreasing the shutter time by one speed (doubling the light).
~NORM
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - NORMAN LENBURG, Photo/Imaging Instructor, Madison Area Technical College, 3550
Anderson St., Madison, WI 53704 USA (608) 246-6521 (voice) 608-246-6880 (fax)
...............................................................................
There are probably manu ways to arrive at the answer you are looking for. I
would approach it from the point of view that a factor of 2 is one stop. I also
know that the log of 2 is .3
From here, if I need an exposure increase
associated with a factor of 2x I find the log of this factor and divide it by
.3 to find the increase in terms of stops.
For example: need an increase of 2x. The log of this factor is .3
divided by .3 the answer is 1 stop
"
"
"
file:///C|/faq.html (381 of 555) [7/19/2002 3:46:31 AM]
3x
The log of this factor is .47
divided by .3 the answer is 1.6 stops
now I if I place both tubes on the camera and use the two "factors" together,
their "power" is multiplied. This is because if I need a factor of two and add
a stop, and then I need (for some reason) another factor of 2 on top of that
I'd open up another stop. The total would be two stops or a factor of 4. Thus
factors get multipled. In the case you mention, 2 x 3 = 6 and thus to continue:
For example: need an increase of 4x. The log of this factor is .6
divided by .3 the answer is 2 stops
"
"
"
6x
The log of this factor is .78
divided by .3 the answer is 2.6 stops
andy, [email protected]
..............................................................................
One of the easiest and most versatile ways to make exposure compensations for
longer than normal lens-to-film distances, or "bellows extension", as it is
often called, is to use a variation of the inverse square law.
To do this, you will have to measure a standard distance from a point on the
lens to the back of the camera. This "standard distance" MUST be equal to the
focal length of the lens you will be using with the tubes. For example, you
mentioned MF, so I'll assume an 80 mm lens. Measure from the back of the
camera to a distance of 80 mm, and note that point on the lens. This is your
normal lens to film distance, or "old extension, as they sometimes say. Now
put on the longest tube you have, and measure that distance again. Let's say
it's 140 mm now. Note: the longest tube will give you the difference between
the two numbers. You actually use whatever will do the job.
The formula is: the new lens extension squared divided by the old lens
extension squared, or 140 squared divided by 80 squared, or 19600 divided by
6400, or 3.06. "3" is certainly close enough. That translates to a one and
one half increase in exposure. So if the meter says shoot at f/11, it's one
stop, or twice the exposure, to f/8, and if you want twice more, or four times
altogether, it would be f/5.6. You want a point in between 5.6 and 8 to equal
a three times increase.
This will become second nature in no time. The nice thing about it is that it
works for 35mm cameras and normal lenses, or wide angle or telephoto lenses, or
4 by 5 cameras with the bellows racked out 3 miles, or what ever else you may
be working with. You can make extension tubes of old paper towel tubes, and it
will work flawlessly. It works for my Robertson Meteorite copy camera, which
takes up to a 15 by 18 inch negative. And it works exactly the same for every
concievable situation.
Summary: take the new focal length of the lens, or the new extension, square
it, (or multiply it by itself if your calculator doesn't have an x squared
key), and divide that by the old focal length, or *actual* focal length,
squared. That is your exposure factor. Increase exposure that much, and you
can't miss. Works every time, unless you really go overboard and start getting
into reciprocity failure.
Math, yes, but if you want to do some serious closeup work without in camera
meters, it's a necessity, especially for slides.
file:///C|/faq.html (382 of 555) [7/19/2002 3:46:31 AM]
John Thompson, Canton, Ohio <[email protected]>
.............................................................................
Oh, gosh, the information you're getting is well intentioned but unforunately
NOT wholly correct! Or in some cases unnecessarily complex. If you are using a
plain extension tube (absolutely no lens elements in it) the amount of exposure
adjustment is dependent upon BOTH the length of the extension tube AND the
focal length of the lens being used with it!!!
In other words, using a 25mm
extension tube with a 50mm lens is a different exposure adjustment than using
the same 25mm tube with a 200mm lens.
You can use this table for your calculation of exposure adjustment.
Extension / focal length
1/10 - 1/5
1/4 - 1/3
1/2
1
1.5
2
Exposure increase in EV
or f/stops
1/2
1
1.5
2
2.5
3
If you're into the real math, you can calculate the Exposure Factor (not the
same thing as exposure increase in the above table...Exposure Factor 4 =
exposure increase of 2 f/stops, for example).
EF = (Magnifaction+1)^2
where Manfication = Extension / Focal Length.
single equation for simplicity:
We can convert both into a
EF = ((Extension / Focal Length)+1)^2
Got that? <s>
--Wilt, [email protected]
.............................................................................
Following considerations has been condensed from a Nikon Sales Manual
(Close-Up Equipment):
"...As the lens is moved further away from the camera body, you are able
to focus closer. To determine the amount of extension needed to produce
a certain reproduction ratio, this equation can be used:
EXT=RR x FL
where EXT is the amount of extension needed, RR
is the reproduction ratio, and FL is the Focal
Length of the lens in mm.
Suppose you are using a normal 50 mm lens and want to shoot at 1x
magnification, how much extension will be needed? By substituting into
the equation, we have:
EXT=RR x FL
= 1 x 50 = 50 mm of extension
file:///C|/faq.html (383 of 555) [7/19/2002 3:46:31 AM]
From the equation, it becomes apparent that the shorter the focal
length,the less the extension needed to produce the same magnification.
Carrying it one step further, with a set amount of extension, the
shorter the focal lenght, the greater the magnification produced.
Therefore, to obtain the greatest possible reproduction ratios when
using extension rings or a bellows unit, use wideangle lenses.
Another fact : As the lens is extended away from the camera,the actual
amount of light striking the film is reduced, thereby requiring an
increase in exposure. A handy formula for finding the exposure factor
is:
EF=(1+RR)(1+RR) where EF is the exposure factor and RR is the
reproduction ratio.
If we are shooting at 1x magnification, let's see what the Exposure
Factor would be:
EF=(1+RR)(1+RR) = (1+1)(1+1) = 2 x 2 = 4
Thus, the Exposure Factor is 4. To find the amount of exposure increase,
you multiply the original shutter speed by the exposure factor to get
the corrected shutter speed. For example, suppose the original shutter
speed was 1/8 sec.. Multiplying it by 4, we have:
1/8 x 4 = 4/8 or 1/2
So, 1/2 sec. is the correct shutter speed to use.
An alternate method is to use the foolowing chart to determine the
number of f/stops of exposure increase needed:
------------------------------------------------------------------Exposure factor
2
3
4
6
8
12
16
24
32
------------------------------------------------------------------Increase in f/stops 1 1-1/2
2 2-1/2 3
3-1/2
4
4-1/2 5
------------------------------------------------------------------With an exposure factor of 4, it's necessary to open up the lens by 2
f/stops, (i.e., from f/8 to f/4).
The above method to get the proper exposure factor is really valid for
symmetrical lenses.
Whwn you use asymmetrical lenses, the difference in pupillary
magnification must be taken into consideration to establish the correct
exposure. The pupillary magnification is the ratio of the exit pupil
diameter to that of the entrance pupil. If "P" represents the pupillary
magnification, the followig formula applies:
EF= (1+ 1/P.RR)(1+ 1/P.RR) (when the lens is mounted in normal position)
When the lens is mounted in reverse, use:
EF= (1/P + RR)(1/P +RR)
Values of 1/P vary depending on the lens used, as below:
(Please have in mind following chart is for nikkor lenses)
file:///C|/faq.html (384 of 555) [7/19/2002 3:46:31 AM]
-----------------------------------------------------------------------1/P
0.3
0.4
0.6
0.7
0.9
1.0
1.2
1.6
2.2
-----------------------------------------------------------------------35/1.4 20/4
28/2.8 35/2.8 50/1.8 45/2.8 85/2 135/2 200/4
58/1.2 24/2
28/3.5
50/2
135/2.8
Noct
24/2.8 35/2
105/4
55/3.5
135/3.5
Lenses
28/2
35/2.8
Micro
Micro
180/2.8
28/4
PC
105/2.5
PC
50/1.4
55/1.2
-----------------------------------------------------------------------I understand that most or all of the above facts are well known by you, but I
believe that, perhaps, the clear explanations given by Nikon could be of help
for other people . Good shooting!
Note 36.01
-< How do Filters and Variable Contrast papers work? >-------------------------------------------------------------------------------> When using variable contrast paper do the filters on the enlarger only
> increase the contrast or do some of them decrease it as well. At what point
> do you choose to change the contrast of the negative. Do you first roughly
> establish the f-stop and time needed to expose the paper and then try and
> change the contrast to your liking?
Variable Contrast papers have two (or more) emulsions. A high contrast
emulsion that is sensitive to blue light and a low contrast emulsion that is
sensitive to green light. When exposed to white light, both emulsions get
the same exposure, resulting in an image equivalent to approximately grade 2
paper. The multigrade filter set has yellow and magenta filters. The lower
grades are yellow and when used block the blue light in the white source.
This causes the green sensitive (low contrast) emulsion to get greater
exposure and lowers the contrast of the print. When the magenta filters are
used the green light is blocked for the opposite effect. The intensity of
the filter determines how much is blocked and therefore you can get grades
from 0 to 5 from multigrade paper. Parenthetically, results may differ from
one enlarger to the next depending on the ratio of blue & green in the
"white" light source.
I print my contact sheets on multigrade paper without a filter and then based
on my examination of the negative and the contact sheet decide what filter to
use as a starting point. Once I have a test print I decide if the grade is
proper. If you are not sure, start with #2 and get the best print you can
get. Then decide if you need more or less contrast. As your printing skills
improve you can get into more esoteric stuff like burning in with a different
grade filter than the rest of the print.
Rich Lubitz ([email protected])
================================================================================
Note 36.02
-< Partial Stop Push/Pull Small Batch processing times >------------------------------------------------------------------------------->What would be the times to achieve partial stop push/pull results when
>processing E-6 films?
file:///C|/faq.html (385 of 555) [7/19/2002 3:46:31 AM]
S/B E-6 push/pull - Kodak gives time for 1, 2 and 3 stop push/pull.
1 stop push (1 stop underexposed)...+ 2 min/or adjust temp +8 deg F
2 stop push (2 "
"
)...+ 5 min/or adjust temp +12 deg F
3 stop push (3 "
"
)...+10 min/or adjust temp +16 deg F
1 stop pull (1 stop overexposed )...- 2 min/or adjust temp -6 deg F
2 stop pull (2 "
"
)...- 3 min/or adjust temp -13 deg F
I have not (as yet) had to try for a 1/3 stop change. I would imagine that you
sould try some experimentation to come within 1/3 stop variation in film
speed/exposure using a control strip and densitometer to evaluate degree of
success.
Ken, [email protected]
..............................................................................
We process our E6 on a Jobo ATL 2. The times shouldn't vary between an
automatic or hand process. It's a function of adjusting for film emulsions,
camera differences and personal preference. We use the following times for
all E6:
+3 stops
+2
+1-1/2
+1
+3/4
+2/3
+1/2
+1/3
+1/4
Normal
-1/4
-1/3
-1/2
-2/3
-3/4
-1
-1-1/4
-1-1/2
-2
- 16:15 min.
- 11:15
- 10:45
- 8:15
- 7:45
- 7:35
- 7:15
- 6:55
- 6:45
- 6:15*
- 5:45
- 5:35
- 5:15
- 4:55
- 4:45
- 4:15
- 4:05
- 3:45
- 3:15
Watch for colour shifts in any variance from normal process times. Pushing
has a tendency to add yellow. We use Kodak's 1gal. E6 kits, mixing 5 kits
at a time. They've shown to be the most stable for shelf life, giving us a
good month before any shifts start happening. Trust that this gets you on
your way.
Steve Grimes, [email protected], Grimes Photography Inc.
127 Albert Street, London ON Canada N6A 1L9
================================================================================
Note 36.03
-< Memorable Photographs and Photographers - partial list >-------------------------------------------------------------------------------M E M O R A B L E
I M A G E S
file:///C|/faq.html (386 of 555) [7/19/2002 3:46:31 AM]
the "short" list!
Mark Murray asked: "Our state photography teachers association is updating a
multiple choice test that we use as one of our on-site contests for high
school students at our state conference. We were talking about some possible
additions to the test and the idea came up that we include some images that we
thought students ought to recognize - both the image and the photographer who
took it.
We have started a list, with such images as:
Dorothea Lange's Migrant Mother
Yousuf Karsh's Winston Churchill
Weegee's The Critic
Adams' Moonrise
Joe Rosenthal's Iwo Jima
I realize the list is almost endless, but if you could identify 10 specific
images that you think high school photography students should recognize
(whether art, advertising or photojournalism), what would they be?"
..............................................................................
Eisenstaedt, VJ Day
A Weston pepper
and something by Cartier-Bresson
Eddie Adams' shot (no pun) of the execution of the Viet Cong officer
Anything by William Wegman with Man or Fay Wray
Roy, <[email protected]>
...............................................................................
Ansel Adams...Moonrise
Eisenstaedt...Sailor kissing a nurse(Don't know the real title)
Robert Capa...D-day
W. Eugene Smith...Spanish Village
Haas...Tulips
and the photograph of the death camp survivers.
P.F. Clemente, Imagepoint Photography, [email protected]
................................................................................
I'd like to add Eisenstadt's absolutely riveting picture of Josef Goebbels
(1936?) and the Walker Evans shot in Pennsylvania through a graveyard, over
workmens houses toward a steel mill.
Ed Lukacs, [email protected]
............................................................................
Some of the photographers you should include (several at
be represented by at least 2 or 3 pictures):
Hill & Adamson
P H Emerson
Bill Brandt
file:///C|/faq.html (387 of 555) [7/19/2002 3:46:31 AM]
least of who should
Eugene Atget
August Sander
Edward Muybridge
Henri Cartier Bresson
Andre Kertesz
Robert Capa
Then there are a few US (or adopted US) photographers you might care to
include, such as:
Robert Frank
Edward Weston
Lewis Hine
Paul Strand
Alfred Steiglitz
Diane Arbus
Walker Evans
Lee Friedlander
Gary Winogrand
Gene Smith
Peter, [email protected]
..........................................................................
"What are all these children laughing at" Bill Brandt
"Ellen Terry" Julia Margaret Cameron
"Pepper No. 30" Edward Weston
"Sleepy day of August" Y.M Kumagawa
"Saut Dans Le Vide" Yves Klein/Harry Shunk
"Stockholm" Laszlo Moholy-Nagy
"Bibi au Restaurant d'Eden Roc" Jacques Henri Lartigue
"Front Street Portland, Oregon" Minor White
"East 100th Street" Bruce Davidson
Any thing (not a title) by John Heartfield
I could go on and on Wyn Bullock, Robert Adams, Cindy Sherman, Helmut Newton,
Joel peter Witkin, not forgetting "Old Ansell"
Graeme Webb, [email protected]
...............................................................................
milk splash
the critic
10,000 soldiers (+/-)
Running Horses and such
Death of a Spaniard
war pictures
Churchill
Marilyn Monroe
1st picture on moon
fashion photographers
Andy Davidhazy, [email protected]
file:///C|/faq.html (388 of 555) [7/19/2002 3:46:31 AM]
by Harold Doc Edgerton
by Weegee
panoramic "cirkut" pix by E.O. Goldbeck
by Muybridge
by Capa
by Duncan
by Karsh
by Eisenstaedt
by Armstrong (actually who took it?)
Avedon
........................................................................
Edward Weston's Pepper
John Kennedy Jr. saluting his father's casket
Gene Smith, Minimata
Marilyn Monroe with her dress flying
Any Civil War photo (Gardner & O'Sullivan)
The photos of Hiroshima after the bomb
The Kent State Shooting photo
The Vietnam photo of the girl running with Agent Orange burns
Man on the Moon and Earth from the Moon
NASA Hubble photos of Comet smashing into Jupiter
Muybridge's motion studies (particularly horse studies)
Stieglitz's Steerage photo
Arbus' twins photo
Margaret Bourke White's Louisville Flood and Buchenwald photos
Anything from Robert Frank's The Americans
Anything by Lartigue, Atget, Brassai, Friedlander, Lewis Hine, Man Ray,
Robert Capa, William Klein, Lisette Model, Cartier-Bresson, Walker Evans.
Substitute any photo of the American West by Timothy O'Sullivan or Carleton
Watkins or William Henry Jackson for Moonrise.
K. G. Zaboroskie, [email protected]
............................................................................
A Daguerreotype
A Brady Print
An Edward Muybridge...take your pick
"The Steerage", Alfred Stieglitz...or one of his O'Keeffes
"Migrant Mother", Dorothea Lange
Margret Bourke-White
"The American Way of Life"
Man Ray
Rosanne Stutts, [email protected]
.......................................................................
I frankly think that some of the pictures listed by Graeme Webb are not
"iconic" enough to be on the list of ten which the original request seemed to
imply--some are a little too obscure and simply have not been reproduced
enough to warrant instant recognition by high school students. Some of the
other suggestions by other folks also were not specific enough. "Anything"
by Robert Frank or John Heartfield wouldn't quite fill the bill. I believe
the most frequently reproduced Robert Frank image would have to be the cover
picture from "The Americans." Also, "East 100th Street" by Bruce Davidson
isn't specific, as that's a whole exhibition and book, not just a single
image. As important as Friedlander and Winogrand are, I can't think of an
individual image by either of them that I would expect someone at the high
school level to recognize instantly. I would suggest that the single most
memorable and most frequently reproduced photograph of all time would have to
be the Lincoln portrait translated into an engraving for the five-dollar
bill! Talk about the "currency" of a photograph!
file:///C|/faq.html (389 of 555) [7/19/2002 3:46:31 AM]
David Haberstich, [email protected]
...........................................................................
For high school students.... shooters, or historians? Photo or photographer?
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Walk into Paradise Garden
Moonrise over Hernandez NM
Lartigue's brother (cousin?) leaning into airplane backwash
Rothstein's Dustbowl
Wynn Bullock's Child in Forest
Capa: Death of a Spanish Nationalist
Brady's Lincoln
Nadar's Mime
River Scene, France
Pepper #35
For a contest... Could they, for example tell if "Satiric Dancer" was Kertesz
or Brassai? How about "La Mome Bijoux"? Distinguish between Walker Evans or
Dorothea Lange? (Not surprised there's little ad or fashion stuff represented
-- it's DESIGNED to be disposable)
Jeez, I just realized, NO COLOR!
(How about Paul Fusco's couple peering over a car door, then?
Or Hiro's jeweled hoof?)
Kevin Bjorke, Space Ranger, [email protected]
.........................................................................
The suggestions on this topic have been conservative and expected. I couldn't
help thinking over and over about the target audience (today's teenagers) and
what would be memorable images for them. This is somewhat off target but in
response to my musing I come up with items like:
ET and company flying bicycles into the sky.
Pamela Anderson looking wistfully out over the ocean.
Jaba the Hut (spelling) with Princes Leah in chains.
Darth Vader with light saber.
Michael Jackson dancing.
Fire at Waco compound.
etc.
This raises questions about comparing still images with moving images. I
suspect the memorable "images" that are burned into the pysche's of today's
teenagers are movie and TV clips.
As for that conservative list, let me add:
Assasination of Oswald.
Planting American flag on moon.
The Challenger explosion.
As I continued to scan the messages on this topic I noticed that someone called
to the group's attention the lack of images from the commercial advertising
industry. This suggestion was made with the implication that such images were
file:///C|/faq.html (390 of 555) [7/19/2002 3:46:31 AM]
not present as they are not worthy.
I agree they are generally less worthy, but they may not be less important. I
submit that a collection of all the memorable images offerred by this group,
when placed on a scale that measures only weight and not value, would fail to
shift the balance against just one image drawn from commercial advertising. I
give you: The Energizer Bunny.
Joe Angert, St. Louis Community College, <[email protected]>
........................................................................
I would like to add to this list the following:
Niepce (sp?)'s first photo image
One of Avedon's Coal Miner Images
Mary Ellen Mark's portrait of the young female runaway in Seattle
(her name is Tiny?)
Cartier-Bresson's shot of a huge hole in a rock wall (assuming having
been done by a mortar shell) with children playing
about.
In reiteration of other posts, let me also vote for:
One of Weston's peppers
An early Wegman, of Man Ray the dog
Chico Seay, [email protected] (Chico Seay)
================================================================================
Note 36.04
-< Photographing a total solar eclipse >------------------------------------------------------------------------------->There will be a full eclipse of the sun in Thailand on Oct 24. I want to take
>eclipse photographs but I'm not prepared. As I know the aperture must be kept
>constant and the shutter speed changed while taking picture. Before totality
>a ND 400 filter is required. What material can I use as ND filter ?
You can still make a test for the uneclipsed pictures by simply photographing
the full disc of the sun this week. Your statement about using f11 (probably
with 100 speed film) and a ND 4.0 filter is reasonable IMO and you'll probably
be using a shutter speed of something like 1/500 second.
Note that the ND filter is 4.0 and not 400 - 4.0 means that 1/10,000 of the
light falling on the filter makes it through BUT BEWARE OF THE Infrared that
gets through in much larger and invisible quantities ... if you get a
photographic quality gelatin ND filter DO NOT use this filter to look at the
sun with ... use itONLY in front of camera lens and then looking at image on
camera viewfinder is generally safe. When totality happens the filter is
removed from the lens.
Negative film is more forgiving in terms of exposure but you can't beat the
brilliance of a transparency in terms separating the fiery red prominences
from the corona and reproducing the pearly white outer corona which is visible
and should be evident in the pictures receiving fuller exposures.
>Is a 300 mm lens too small for this?
file:///C|/faq.html (391 of 555) [7/19/2002 3:46:31 AM]
No. A 300mm lens will give you an image of the sun which is about 3mm on the
film or about 1/10 the size of any full frame enlargement made from the film.
In fact interesting photographs of the partial stages of the eclipse can be
made with much shorter lenses. For example you could use a 50mm lens and then
take several photographs on the same frame (with multiple exposure) showing the
several stages in the approach and receding stages at either side of a frame
showing the full eclipse. Pictures like this are common but in spite of the
fact that I've seen two eclipses I don't have one (and it is one I dearly would
like to have made!)
>For instance Before full eclips, using f11 meter light by camera meter and
>speed is 1/125. I must do a compensate using 1/125, 1/60, 1/30 , 1/250, 1/500
>and 1/1000, is this right?
I don't think that bracketing during the partial stages does anything other
than waste good film. If you wanted to assemble a "series" or make a flipbook
or such I would spend the film on making many exposures rather than bracketing
wildly. Making a test beforehand (as suggested above) would still be a good
thing to do to reduce the need for bracketing.
>When eclips is full, take off ND filter, use f11 and take photo with all
>shutter speed, is this right? Any more suggestion would be appreciate,
Well, I think that exposures in the 1/250 - 1/1000 second area are really too
short during totality. You will probably want to bracket from 1/60 second to
about a second or so. Due to the small size of the sun it will be impractical
to make a light meter reading either during partial or total stages. Exposure
times beyond 1 second may exhibit significant blur due to rotation of earth. I
would suggest you open up a stop or two if you are trying to get an extended
picture of the corona.
You may have difficulty getting a ND 4.0 filter in your location. There are
Mylar filters that will probably be sold in your area to view the partial
stages. If I recall correctly these can be also used for photography. BTW ...
use a good tripod and tape the lens barrel so that you don't change the
position of the lens from infinity focus.
finally ... here is a wish that you have a nice clear sky!
andy, [email protected]
================================================================================
Note 36.05
-< Photo Mailer Supplier >------------------------------------------------------------------------------->Does anyone have a good supplier for heavy cardstock mailers for photos? I
>need some in 5x7 and 8x10 sizes for mailing photos to customers safely. I'm
>tired of stuffing cardboard in manila envelopes.
I get mine from Calumet Carton Co., 16920 State St., P.O. Box 405, South
Holland, IL 60473. Phone: 708-333-6521. Ask for their catalog. You can
order by phone, they ship UPS, and you have 'em in a couple of days.
They're great! Hope this helps.
Michael Tappin
[email protected]
Northeastern Illinois University
5500 N. St. Louis Ave., Chicago, Illinois 60625
file:///C|/faq.html (392 of 555) [7/19/2002 3:46:31 AM]
================================================================================
Note 36.06
-< Minox film supplier >-------------------------------------------------------------------------------The US Minox lab and the service station is: Minox USA, 250 Meachem Ave.,
Elmont, NY 11003, 516 437-5750.
This is the only factory approved and authorized processing lab in the U.S.
Any dealer can order film from us and supply you with it or you can buy it
from the lab. They also sell processing mailers.
Bob Salomon, HP Marketing Corp., Giottos, Gepe, Heliopan, Kaiser
Fototechnik, Linhof, Minox, Rimowa, Rodenstock, Rollei, Silvestri
================================================================================
Note 36.07
-< Two comments on Pricing Weddings >------------------------------------------------------------------------------->I'm just curious about some wedding pricing. Our photographer was telling me
>that he only made about $50 dollars profit on our wedding. Does this sound
>right? He took about 200 to 250 pictures. Our package included: 1 11x14, 8
>8x10, 7 5x7, 10 wallets and 100 4x5 proofs in padded album. We paid about $800
>for this package. This just doesn't seem right to me.
Basis of my information is that I have done wedding photogaphy since 1984 in
both 35mm and medium format (6x6). I have worked all levels of the market.
I am going to have to make some assumptions, since you have not given complete
information. The 4x5 as a proof size indicates that the origination format was
6x4.5 cm, the smallest of the medium formats. Had the pictures been 3.5 x 5 or
4x6, that would indicate 35mm format. The original posting went on to say that
the photographer in question was part time, however that doesn't mean a full
time photographer is always better. Professionalism - and lack thereof - know
no bounds.
Format makes only a slight difference in cost of enlargments - some labs
actually charge more for prints from 35mm than they do from medium format!
So, on to the estimate of costs this photographer probably faced:
Film: 240 shots/(30 sh/roll in 6x4.5) = 8 rolls @ $7 = $56
Proofing: 240 shots @ .70 (pro lab) = $168
Enlargments: 10 + 8x4 + 7x2 + 5 = $61
Album: Spiral bound, celluloid page type = $25
Misc. Expense: Batteries, car travel, shipping t/f lab = $35
Total Direct Expense = $345, say $350
There are also indirect, or overhead expenses that are part of any business
operation, whether or not the proprietor or client recognizes them. These
include phone, business liability and equipment insurance, office supplies,
equipment repair and maintenance, and advertising. I assume the photographer
under discussion here works from his house and has no office rent expense. He
may or may not be in a pro association. Assuming he does 15-30 wedding jobs
per year, his overhead is probably running at about 70% so his total costs on
the job are $245, say $250.
file:///C|/faq.html (393 of 555) [7/19/2002 3:46:31 AM]
So his real cost of doing this job, per my estimate, is probably around $600.
If he does far fewer jobs per year his per job or has a lot tied up in
expensive equipment, than his overhead cost may be up to $400 per job, which
could conceivably make his so-called profit = $50. If he shot 35mm instead of
medium format, the only saving would be the per shot cost of the film and
possible less amoritzed equipment expense.
So we know he made between $50 and $200 on this job. Consider the time to do
it: 2 hours for booking the job and planning the shoot, 3 hours for charging
batteries and preparing equipment, 7 hours on location for photographing the
event, and an additional 8 hours for working with the lab, filing negs,
assembling the proof book, and meeting with client; total time estimate is 20
hours. Realize that no bridal album design is in this job; such would add
another 10 hours of work. So, he grossed between $2.50 and $10 per hour.
>We went through a lot of hassle with this guy. He even threatened to not give
>us our pictures because he claims he ran into one of our friends who told him
>the pictures stank.
Not a pleasant experience for a photographer, but still, no excuse. How did
this friend get to see the pictures before you - the client? If he had held
them back, you'd have the basis for a lawsuit, probably in Small Claims Court.
>He was very unorganized. I had to sort through the proofs for 4 hours when
>we decided which ones we wanted because he had no ordering system. We still
>don't have our pictures after 2 months.
Wedding labs take a few weeks to turn orders around. They do more with the
pictures than do consumer labs. The more sizes there are in an order, the
longer the time takes. It is not unusual to have a 4-8 week photographer
turnaround for enlargements and 10-16 week production time for albums. Much of
the time is due to the fact that the studio doensn't drop all other work to do
your thing. However, I do not condone the lack of organization and sloppiness
of this one in question.
>Maybe I'm wrong and this is just how it works. It just doesn't make sense
>that someone would go through all the hassle for a lousy 50 bucks.
Chances are, he earned more that 50, but not a whole lot more (see above
calculations). What would your job attitude be if your pay were set equal to
that level?
>PS: This wasn't a professional studio, just someone who does photography "on
>the side."
I very strongly agree that the studio as described, based on statements and
actions, was very unprofessional in its conduct. Unfortunately, the original
poster said nothing about how the pictures looked and how the photographer
behaved at the wedding - both are VERY IMPORTANT considerations. Whether the
phtographer is full or part time has nothing to do with the problems discussed.
Two failings occured in this account. (1) The photographer has succumbed to
serious price competition and has let the low per/hour take affect his
attitude. IMHO, it is wrong to accept a job and have a nasty attitude; better
off raising prices and being courteous to clients and their guests. (2) This
file:///C|/faq.html (394 of 555) [7/19/2002 3:46:31 AM]
probably looked like a good deal, pricewise, to the people who booked the
photographer. I think they put too much priority on price, or for some other
reason, did not fully check out this guy's past performace.
/|/| /||)|/ /~ /\| |\|)[~|)/~ | Everyone's entitled to MY opinion.
/ | |/ ||\|\ \_|\/|_|/|)[_|\\_| | [email protected]
========Imagination is more important than knowledge. - Albert Einstein=======
..............................................................................
>So what *is/are* the *average* price for a standard size 8x10 wedding print
>with and without touching up any blemishes, etc.? I use mainly the machine
>prints without touch ups and charge about 1/2 the price that most pros in
>town charge. At the pro lab that I go to, they have the option of pro machine
>prints and custom prints (the custom prints of course costs about 3 times that
>of the pro machine prints). Do the "pro" wedding photographers normally do the
>"custom" prints (which includes dodging, etc. but no touch ups) for their
>standard prints or are the pro machine prints sufficient? Also, with regards
>to touch-ups, do most wedding photographers have all the prints touched-up?
>or does the client have to specifically request it and pay extra for it?
The retail price charged varies from market to market and from photographer to
photographer. In general, you should ensure that you mark up your work a
*minimum* of 200%, with 300% to 400% or more being realistic. If you are
selling your wedding packages at 1/2 of what "most professionals in town
charge", then you are probably undervaluing your work.
Contact your local Better Business Bureau or Chamber of Commerce and find out
what the average wedding package costs in your area. You will find
photographers who charge three or four times the average, but you should try to
price your services so that your average sale is *at least* at the average.
I look at "low end shooters" kind of like a chef who pees in his stew.
Eventually, no one else wants to eat out of the pot, but what is he left with?
A boiling kettle of piss.
Remember that as soon as you charge people to photograph their wedding (or
their baby, or their family, or their highschool kid) you *are* one of the
professionals in town. You are also in business, whether you like it or not,
and have an obligation to conform to your state or provinces tax regulations.
You also have an obligation to conform your work to contemporary professional
practices.
If you are serious about selling your work, my recommendation is to
*immediately* contact your local chapter of the Professional Photographers of
Canada. You can find the chapter by calling any of the photographers listed in
the Yellow Pages, especially those with letters behind their names like "M.
Photog." or "CPP". Join your local chapter and, as you become established, the
Professional Photographers of British Columbia.
Don't try to build a business "on the cheap". If you don't already have one,
invest in a good, professional-quality, rollfilm camera. It doesn't have to be
a Hasselblad with six lenses, an old Rollei or Mamiya C330 will work just as
well. It is impossible or *very* expensive to have negative retouching done
on 35mm originals. On the other hand, most professional color labs have
retouching services available for a nominal charge. My lab charges $6US per
negative to correct for zits, eyebags, glasses glare, etc. _on the negative_.
file:///C|/faq.html (395 of 555) [7/19/2002 3:46:31 AM]
Find a good professional lab close enough that you can drive to it. Ask about
portrait package services as well as autoprinting. A professional lab offers a
range of services that no minilab can provide, including negative retouching,
lacquer spraying, dry mounting, canvas tranfers, transvue proofing, etc. A
good lab will save your skin every time, but expect to pay 10% to 30% more than
you will at a minilab.
As for your specific questions, most wedding albums are produced using auto
prints. Each print should be finished, however, with a spray lacquer,
especially if the album, like Art Leather and Renaisance, has open pages. The
lacquer protects the prints against finger prints, water spills, etc.
Custom printing services are typically reserved for special cases like
competition prints, "premium" portrait services, or to fix a screw up. Again,
it varies from photographer to photographer. People like Monte Zuker retouch
each negative, before the customer ever sees a paper proof, but Monte offers a
*very* high-end premium service at a premium price. Most of us don't have
that luxury.
With practice, as you learn the craft, you will learn to use things like
vignetters and diffusion filters that give you the appearance (edge burning,
montages, etc.) of a "custom" print directly from a negative. It is *always*
preferable to create special effects in the camera. This ensures that no
matter who prints that negative, or when that negative is printed, the effect
*you* desired is always rendered.
My own policy on retouching is flexible. My wedding price list indicates a
$10 per negative charge for retouching, but in practice I will voluntarily have
a limited number of negatives fixed, especially if it's to correct glasses
glare or a shadow on the face. If the bride wants to have 40 negatives
retouched because she had a zit on her wedding day, well, that's another
story. It has never happened to me.
For portraits, I include the retouching with any display sized print 8x10 or
larger, but charge $10 extra per negative for smaller prints. I simply don't
have enough profit margin on the small prints to eat the retouching charge.
I learned about my profit margin, by the way, the hard way from a highschool
girl with a bad complexion who ordered 16 5x7 prints, all from different
negatives. Her order grossed around $400US, but my lab charges were almost
$300, with almost $100 *just in negative retouching*. This was an isolated
case, but I changed my policy almost immediately afterwards. Fool me once,
shame on you, fool me twice, shame on me.
Of course, if the smaller prints are made from the same negative as a display
print, the retouching is included at no charge. The nice thing about negative
retouching is that once it is done, *all* prints made from that negative are
corrected.
Hope this helps.
-fred
From: [email protected] (Fred Collins)
Organization: The Light Fantastic Fine Photography
file:///C|/faq.html (396 of 555) [7/19/2002 3:46:31 AM]
================================================================================
Note 36.08
-< Basics of Unsharp Masking - what it is and how to do it >-------------------------------------------------------------------------------> Being somewhat of a novice to Photography, i am quite unfamilar with what
> technique you are referring to. What is being done using this technique and
> what is the desired outcome? Please e-mail me if you have the time. Also:
Unsharp masking for black an white negatives "is a method of reducing overall
contrast (or density range) of a negative so that it can be printed on a
higher contrast paper. Because the mask is unsharp, the DETAILS RETAIN LOTS
OF CONTRAST! That's the really neat part that I have never found another way
to achieve besides dodging and burning (let me add that I am just beginning
to try out the technique).
To explain the summarize the process, I will assume a glossary...
mask - a negative specifically designed to be set on top of another negative
during the print exposure.
unsharp - "out of focus", "soft", etc.
density range - the difference in units of density between the thinnest part
of a negative and the thickest part
gamma - slope at any given point of a curve (function) plotted of density as
a function of exposure
So, given these terms:
The technique involves measuring the density range of the negative you want to
print, deciding what the optimum range should be, to print on the paper that
you are interested in, and then the creation of a mask. The mask is created
by exposing B&W film while it is in "contact" with the negative that you are
interested in printing. The reason "contact" is in quotes is because in order
to make the mask unsharp, a clear piece of plastic of predetermined thickness
is inserted between the negative and the masking material. Once the exposure
is made, the mask is developed according to -plan- (i.e. the planned density
range for the mask) and then it is available to use during printing. To print
the "corrected" negative / mask combination, the sandwich is placed into the
enlarger, and exposed.
The results are that since the mask is "unsharp", the details retain the gamma
(local contrast) of the original negative, but the large areas take on the
contrast of the sandwich of mask and negative. The degree of unsharpness will
also cause some interesting "edge effects" between light and dark areas,
actually making them appear sharper.
-hal kraft- [email protected]
..............................................................................
Basic Instructions for Making Unsharp Masks
CHEMISTRY: SET UP 7 TRAYS. The first two are for developer, the third for
water, fifth is a rinse sixth hypo clear and ths seventh for washing.
file:///C|/faq.html (397 of 555) [7/19/2002 3:46:31 AM]
DEVELOPER: Use HC110, mix 1-3 with water then dilute this solution 1-9 for one
tray and 1-15 for another. You should end up with 1/2 inch of solution in each
tray. Temperature of all solution should be 68 degrees F.
Exposure Approx 2 footcandles of light at film. (Suggested exposure with
Chromega Head @ 60 cm from film use f/8 for 3 secs.)
Description of film/glass/diffusion placement for exposure
Glass
original
Diffusion material
Masking Film
**********
++++++++
$$$$$$$$
&&&&&&&&
(emulsion up)
(emulsion up)
(emulsion up)
surfaces must be spotless!!
PROCESSING: Process two sheets (exposed the same) one in each of the trays of
developer. This gives you two differant contrasts. Fix and wash as you would
normal BxW film.
Do not use heat to dry film as this could cause slight skrinkage ,making it
difficult to register the film. Keep your wet time to a minium by using hypo
clear. This will keep your grain to a minimum.
REGISTER THE MASK: I use a loupe, light table, silver tape and a little
patience. Diagram:
Glass
mask
original
Glass
++++++++
&&&&&&&
#########
++++++++
(emulsion up)
(emulsion down)
A more complete discription can be found in Exploring Color Photography by
Robert Hirsch. I would also like to thank Scott Vlaun of Santa Fe for his
premission to post this info to the Photforum List.
Shaun, Camera Graphics Photolab, ALbq NM 87106, [email protected]
================================================================================
Note 36.09 -< Reversal Procesing of B&W Infrared Film for Speed and Slides>------------------------------------------------------------------------------->For the IR-freaks: In the German magazine Foto & Labor 4/95 (July/August)
>there was an article about _reversal processing_ of Kodak High Speed IR film
>resulting in a slide film with 1600 ASA! YES, _SIXTEEN HUNDRED_ ASA, without
>any losses in the IR and highlights characteristics! The author of the article
>used a selfmade equivalent of the Kodak reversal process D-67.
Since other persons have convinced me to send them a summary of the article,
it is only fair that I send it in this list also:
Since most of you probably can't read German, the original article (copy or
back issue) would not help you much. You might first try to run the origina
lD-67 Kodak reversal process 'by the book'. If that fails, you can use the
following translation, but be warned: I have no technical/chemical
German/English dictionary, so there might be errors in it! You might want to
file:///C|/faq.html (398 of 555) [7/19/2002 3:46:31 AM]
use the Kodak manual anyway, to understand my poor translation better. If
there are strange things in my list, please tell! And if things work out ok:
promise to send me a note! I am very curious! (I have no darkroom experience,
I am still looking for someone who will perform this process for me....;-))
D-67 homemade *equivalent*
First developer D-67
distilled water
250
Metol
1
Sodium Sulfite (anhydrous)
45
Hydroquinone
4
Sodium Carbonate (anhydrous)
23
Potassiuom Bromide
2.5
Potassium Kaliumrhodanid solvent (50%) 2.5
Potassium Iodide solvent (1%)
2.5
ml
g
g
g
g
g
ml
ml
Bleach R-9
distilled water
Potassium Dichromate
Sulfuric acid (98%)
980
ml
9.5 g
20 ml
Clearing Bath (CB-1)
Distilled water
Sodium Sulfite (anhydrous)
1000
90
ml
g
Second Developer - any vigorous developer like Dektol, Neutol, Eukobrom Fixer
any ordinary Film fixer
TIMING (all in minutes, at 24 degrees C)
first developer
stop
bleach
rinse
clear
12
3
3
3
5
rinse and 2nd exposure 3-5 (continuous agitation under water, while
film to intense light is recommended)
second developer
stop
fix
final wash
4
1
3
10
Total time
47-49 minutes
exposing
From: Willem-Jan Markerink <[email protected]>
================================================================================
Note 36.10 -< Pellicle mirrors in fast motor drive cameras - disadvantages? >-------------------------------------------------------------------------------file:///C|/faq.html (399 of 555) [7/19/2002 3:46:31 AM]
>Re: pellicle mirrors built into cameras capable of 10 frames per second it
>seems few mention mention light loss. It seems obvious that if light is
>diverted away from the film, i.e. to the viewfinder, your exposure has to be
>compensated with a wider aperture or slower shutter speed as the film is
>receiving less light. The question: 1) is this in fact true and 2) how do
>people feel about the advantages over the disadvantages?
This was essentially one of the major reasons that
sport a pellicle mirror failed in the marketplace.
the fact that photo purists panned the presence of
and the film plane as a cause of less then optimum
the first SLR camera to
The Canon Pellix. This and
a mirror between the lens
sharpness photographs.
The current situation is a bit different. Today many cameras have inherently
long time delay between activation and actual picture making ... or as Norman
Goldberg (I believe ... or maybe it was Bennet Sherman) called it they suffer
from extreme "time parallax". So having a fast-acting camera around is handy.
To get 10 fps and higher the presence of a flopping mirror is a hindrance to
high framing rates. So the pellicle alternative is one worth looking into. You
are obviously not going to be using long exposure times or shooting in dimly
lit interiors if you are going to exploit the 10 fps and higher framing rate
range. To get this you may just choose to give up on the light transmission
potential of the optical system.
Maybe a camera system could be designed that would give you a top framing rate
of let's say 5 fps with the mirror flopping but which could be set to mirror
lock-up position and in which case the camera then might be capable of 15
frames per second ... at the expense of through-the-lens viewing and focusing.
You'd track your subject through a separate optical finder much like a
rangefinder camera does. Something has to give.
andy, [email protected]
================================================================================
Note 36.11
-< Setting up a basic B&W darkroom with color possibility >------------------------------------------------------------------------------->Is there such a thing as a simple darkroom? I'm in college (still living at
>home and i want to set up a simple darkroom. How can i go about doing this?
>Please be as specific as possible and remember i'm still new to all this.
>I now that there will be chemicals, enlargers etc, but what are the bare bone
>essentials to develop 35mm film and make 3x5 and 4x7 prints?
You can put together a simple darkroom very frugally. First you need a dark
room! Bathrooms will do, but I prefer cellars, as you can print during daytime.
Find a cheap 35mm enlarger such a s a BOGEN. You can find these at yard sales
for as little as 20 dollars. You will need an enlarging lens and negative
holder, but these should come with the enlarger. For Black & white you need a
red or yellow-orange safety light. Try the red fireball types which screw into
a regular light socket
It helps to get a timer to make your exposures accurate, get a nice old
fashioned Gray-Lab which is built like a tank and can be used to time film
also. You will need trays to process paper. Get liquid chemicals as they are
simpler & safer to mix. You can get trays pretty cheap from the photo store or
yard sales.
file:///C|/faq.html (400 of 555) [7/19/2002 3:46:31 AM]
For washing I would locate a used Kodak Tray Siphon or one which can convert a
sink. For drying just use a clothes line and pins. When you move up to fiber
make drying screens from the hardware store.
That's it! If you want to spend money, spend it on a good enlarging lens.
Russ Rosener <[email protected]>
.............................................................................
A simple darkroom can be set up anywhere that light can be excluded. If you
limit yourself to 35mm then the enlarger is much less expensive. Often you can
find the equipment in the want ads when someone who set up a darkroom has
either moved on to bigger and better or lost interest. Although running water
in the darkroom is helpful, it is not absolutely necessary. A tray can be used
to keep prints in to be carried to the running water. For film processing, a
changing bag is all the darkroom necessary, the rest can be done at the
kitchen sink. Kodak has a pamphlet about setting up a darkroom. I think it is
a freebee. try http://www.kodak.com
Rich Lubitz ([email protected])
...............................................................................
Ok...here is a pretty bare bones list. I would recommend you check your
library to see if there aren't some books on the topic to give you some better
ideas about the process and what is needed.
For film:
Developing Tank (approximately $25 new)
Bottle cap opener (to pop the top off of the film canisters)
Scissors
film clips (Clothes pins will work here)
Thermometer
Timer (Your watch should work.)
Chemicals: Developer, Stop Bath, Fixer (Assuming Black-and-White)
Bottles for chemistry (Plastic liter pop bottles work OK if washed,
re-labeled, and stored so noone might mistake them
for bottles of pop.)
For the prints: (In addition to what you need for the film)
Safelight
Easel (or something to hold the paper on the enlarger stand - tape?)
Enlarger (lens, negative holder) {Approximately $200}
Trays (Pretty much any non-metal tray should work)
Print tongs (about $3 for bamboo tongs)
Printing Paper
Chemicals: Paper developer
Bottles for Chemistry
Most any room will work at night with just a dark cloth over the windows for
printing, but you need total darkness for loading the film into the developing
tank.
file:///C|/faq.html (401 of 555) [7/19/2002 3:46:31 AM]
>Find a cheap 35mm enlarger such a s a BOGEN. You can find these at yard sales
>for as little as 20 dollars. You will need an enlarging lens and negative
>holder, but these should come with the enlarger.
I agree, but don't
believe that Omega
that should be OK.
sure it is sturdy,
compromise too much here or you will be dissapointed. I
makes a beginners enlarger that sells new for around $200
Used would certainly be the way to go though. Just make
and has good optics.
Just use your watch or a kitchen timer and Trays aren't that expensive, but
most anything non-metal should work here.
As for liquid vs. dry chemicals ) I think that there is a lot of personal
preference in this. Powders are not hard to mix. Liquids might be safer to mix
due to less dust.
Just wash your prints in the sink. Open the drain a bit at the bottom
the fixer drain, and keep a stream of fresh water flowing.
to let
For drying just lay the prints on pieces of paper towels.
Wayde Allen, <[email protected]>
..............................................................................
Speaking of reasonable used enlargers, try to get the Omega A2 35mm or the
great little F 30 made by Durst. The Durst is excellent because the film
carrier and lens housing can be tilted to 90 degrees for making huge
enlargements. Invest in a good lens -- like a Nikkor for it -- and you have a
lifetime+ system at very little cost.
The Omega A2 came with a fine compact Wollensak lens that still gives me
service for my personal B&W work. The Omega is a condenser type that produces
very good contrast while the Durst is more diffuse in effect, but for that it
minimizes negative imperfections. Both enlargers are rugged. The Omega is
very precise. The Durst is convenient and versatile. Both take B&W and color
filters. Both are compact and easy to store.
I've seen Time-O-Lite timers at yard sales. These are indestructible and
electrically time exposures with absolute consistency. No digital timer can
compare with them for hands-on response. Even if they've been neglected on
the outside, the action inside is almost indestructable. They're industrial
grade instruments and are still being made, I think. They're built like
tanks.
As for easels, my favorites turned out to be metal Sped-e-zels for the basic
size prints: 3-1/2 x 5, 4 x 5, 4 x 6, 5 x 7, 8 x 10. They're reasonable and
are still available. Low cost adjustable easels, like the Bogen, are great
for fancier compositions.
If you use Kodak RC papers, fixing and drying are very fast. A simple rack
(used for dishes) will do the drying job up to 5 x 7.
Safelights are still very low in cost. Kodak made splendid little plastic
dome units that used C 7 clear lamps. One is all I ever needed. It easily lit
an 8' x 10' room.
file:///C|/faq.html (402 of 555) [7/19/2002 3:46:31 AM]
Now, with the availability of cheap individually switched electrical outlet
power centers for computer use, it's easy to operate all units from one
convenient location. The illuminated rocker switches may be a problem, tho.
A 12" paper trimmer will also be helpful. I've seen these at yard sales from
time to time. Avoid any trimmer that has plastic in its construction.
I hope the above will be of some help.
BR, From: [email protected]
.............................................................................
Re: a print washer, I have used the old Rubbermaid, or similar, dish washing
tray for years with great success. But one thing, drill about a half dozen 1/4
inch holes along the bottom of one "end" (NOT the bottom itself) so the fixer
can drain, too. Fixer, I believe, is heavier than water.
Can't use the tray for draining crankcase oil anymore with the holes, but you
can't have a fire on a boat. Wait...... Oh! Now I remember,,,,,,, "You can't
have your kayak and heat it, too".
John Thompson, Canton, Ohio <[email protected]>
..............................................................................
I simply cannot resist commenting. I remember from my begiinner days years ago
that far less than this was actually necessary. Developing Tank (approximately
$25 new) but Film can be processed in a tray and a pyrex baking dish is what I
used from Mom's kitchen
To pop the top off of the film canisters I have used screwdrivers and even
teeth for this. Even an old nail will do
Use Clothes pins instead of film clips they will work here, they do
beautifully! Thermometer is as necessary as breathing and it should be fairly
accurate. It does not need to be a laboratory type.
Timer ... your watch should work. (The inventors of Kodachrome film used violin
music for a timer.
Safelight ... Total darkness works. Is anyone old enough to remember VELITE
paper processed in subdued room light?
Easel... The easel I use to this day is two 1X2 pieces of wood nailed together
to form a right angle and stapeled to a piece of matt board to which the
correct paper dimensions have been drawn. I have bought many easels through the
years, but none I likes as wll as my homemade easel.
Enlarger ... use piece of glass for contact frame?!?
Print tongs ... B/W photochemistry will not bother most people. I have used
fingers all my 54 years of life.
Use these things and, in your simple darkroom you can be like me: a simple
darkroom worker! :-)
Charles Knight, [email protected]
..............................................................................
There are a lot of books that are very cheap (under $10) that will not only give
you a guide to developing/printing, but also give you everything you need to s
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tart a darkroom, and also suggestions on how to physically construct it & ideal
locations for all the things you'll need.
The Kodak Guide to B&W printing is a good example. Its a thin booklet, very inf
ormative, and about $8.00
...........................................................................
>one more thing: How is B&W different from color in the processing and
>darkroom area? I know that B&W is easier (i think) than color but what is the
>real differance?
Many books have been written on this. First, temperature control is a whole lot
more critical, there are four things to deal with, the exposure and then the
individual exposure of each of the three emulsion layers. Then there is the
processing. It is all more difficult. With color, to have consistent and
repeatable results and yet not expend an amount of time that only a dedicated
hobbyist would spend, some form of automated processing, though not absolutely
essential, is so desirable as to be almost so. Yes, it's harder, but it is also
much more rewarding. As far as processing color slides is concerned, it is only
a little more difficult, but the temperatire control will need to be within
about a half a defree F. I know the books call for closer, but 1/2 degree will
bget you starteed with good results. In fact, even one degree is okay for the
first few rolls, but you won't be happy with that in the long run. By the way,
temp control to that degree is ONLY impotant in the developer. In the other
steps the process essentially goes to completion and can vary by much more than
the books say. Of course, when you get colder, you have to leave it in a bit
longer, but then I am not writing a book. When you are a beginner, you will be
surprised how far you can deviate from the spec sheet and get good results.
After you have done a few rolls, your standards naturally grow higher and what
once satisfied, no longer does. Color is incredibly rewarding, though. I
remember once that I had a friend who worked for Kodak many years ago. He
"stole" some used developers and I processed several rolls of Kodachrome in a
small tank. The results were surprisingly good for the poor equipment I had. I
would not want to repeat the experience, but then I am glad I did it that one
time. It makes all other color processes look like Sunday school!
Note 37.01
-< Is Photography Finished? >
-------------------------------------------------------------------------------Is Photography Finished?
Personal reflections on the future
1
I originally intended this piece to be an amalgam of electronic mail messages
between myself and four other photographers I have been in communication with
in the US and Europe, on the subject of the future of photography. When I had
edited these, I re lised that we virtually agreed on all the points that had
been raised, but there was too much bias towards the technological arguments
that made the answer to the above question probably yes, as we know it. So, I
decided to write a short piece that wil hopefully stimulate some dialogue and
raise questions as to where we as independent photographers may find ourselves
in the next few years, in the way we think, communicate our visions, produce
our images and ultimately show them to the rest of the wo ld.
I have been to several gallery exhibitions recently, staged for groups of
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independent photographers in the UK. These are mostly people like you and me
who don't have to earn a living from the medium and who are involved in
photography because they enjo it, find it therapeutic or have a calling (some
are actually quite good at it as well). In all these shows (and I must assume
that some form of selection takes place) we are probably seeing the best of a
particular group. I must admit that I have left each one of these venues
feeling that contemporary photography has not evolved in any way. In fact
thinking back over the last few years nothing seems to have changed much at
all. Contemporary photography in the UK appears to be in a rut. One of the pr
blems with working in groups is that although they can be useful as sounding
boards and have some social and educational significance, influences can become
so powerful that the cross fertilisation of ideas and central philosophies can
make a group exh bition look as though it is the product of one or two
photographers. Some photographers I feel tend to take themselves all too
seriously. There is an enormous amount of depressing subject matter on show
most of the time, and the obsession with death and decay seem often to be at
the top of the agenda. Of course most of these images are black and white and
this gives them the essential gloominess that makes them excel in this field.
Is it fashion? So many years of Tory government? Or are some photographers just
manic depressives. The public gallery areas are not much better, with their
arts council funded, politically correct, unintelligible images that are
increasingly bogged down in semiotics. Pictures for academics and not people.
All in all a pretty sad affair. Does photogr phic art have to be so depressing?
Have we all looked too deeply into ourselves?
Isn't it about time that we had some fun?
2
The Royal Photographic Societies membership in the UK has anguished with its
self for the last two years on the subject of digital imaging, which is quite
interesting, as it has nothing to do with imagery as such, only the way that
the image is produce . There are of course ethical issues such as the owners
copyright of a photographic image, although this area will need re-evaluating
shortly as the accessibility of imaging technology increases and the old
barriers of non-silver/silver and digital ima es is broken down. I now believe
that the RPS membership are at rest now after this torturous (and at times
extremely boring) process, and now we learn that the society itself is girding
its loins for the Information super highway. We have been told that the society
will have Web pages shortly, which the rest of the 40 million people in the
world who are on line will have access to. This is exiting isn't it, because if
You had a Web page, 40 million people could access your photographs as well.
There are photographers ot a million miles away from this copy of Inscape that
are doing this already with some success.
The following is a short section from one of the Emails I received recently
from a multimedia teacher in Atlanta on this subject:
..........With the massive increase in growth of the Internet and particularly
the World Wide Web, it is now quite easy for millions of people across the
world to get access to the work of a completely unknown Photographer, to read
about and even to print off hard copy of the images almost instantly. You don't
have to wait anymore for the galleries to show your work (even if you have one
interested in you) they all tend to be regional anyway, with the WEB you will
even find people who are not even in erested in photography looking at you
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work, that can't be bad can it............
This technology, and I include Digital camera's, Personal Computers, Compact
discs, digital image manipulation and fibre optic communications will have an
enormous impact on the way that we think, feel and produce our images, we must
not forget either, the way that the spectator will view the finished product.
As always with the increase in communication comes the dissemination of
knowledge, and the Internet holds host to large numbers of news groups
specialising in all types of photographic interests, they are nearly all active
and if one is subscribed to t em all, then a total of 1000 electronic mail
messages arriving at your Personal Computer a day would not be out of the
question. Photographic Web pages abound and new ones appear by the hour.
Imaging and video editing software is available as shareware for free. If you
have a scanner and an idiots guide to hypertext mark-up language (and someone
will allow you space on a Web server) then you can have your pictures up and
running and available for the world to see in hours. You have suddenly become
a presence in world photography, a global artist like so many before you. What
you suddenly find is that that your horizons have got larger and the world has
become smaller, you have joined a virtual tribe of photographers, whe e you
will certainly come across others that are obsessed with death and decay
(digitally manipulated in black and white of course, but thankfully in a
minority).
3
All business organisations are striving for greater efficiency and control of
their bottom line, and the photographic trade is no exception. Although new
conventional photo emulsion technologies are still developed we are starting to
see films and pape s that are basically the same, and a flattening of the large
manufactures ranges. Small manufactures strive to fill the gaps with the more
esoteric products and although competition is difficult some are doing well.
Unfortunately some products are just disappearing without trace, or
reappearing, packed with the environmentally unfriendly bits taken out of them.
Green solutions to problems of photographic chemical waste are being sought
(more so in the USA then the UK) and in an effort to become green r, profitable
and more efficient some photographic studios are taking advantage of imaging
technology in a big way. This will have repercussions on the amateur and
semi-pro areas as the larger manufactures invest more in the development of
this type of technology, and less in conventional silver based products.
An interesting by-product of these changes is that there appears to be a
backlash from one area of the photographic fraternity. The Gummers are on the
ascendant. There is a tremendous amount of interest in alternative photographic
techniques, paper mak ng, bichromates, cyanotypes, vandyke, printing out papers
etc. There are several very active Internet newsgroups and lots of Web pages, a
well-known photographic book retailer told me recently that they are selling
more books on the subject then ever b fore. This maybe a reaction to digital
imaging by some photographers, these images tend to be unique, in as much as it
is difficult to produce the identical image and colour each time, and they tend
to be sought after as 'fine art objects' for their su tly colourings and
texture. Straight photographs have a lower currency value and can be produced
virtually identically over and over again by traditional printing methods,
photomechanical processes, and now by imaging technologies.
4
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What does this all mean for the future of traditional photography and the way
that the independent photographer thinks and feels about the medium?
Electronic image manipulation and production is hear to stay, and should not be
feared. It opens up possibilities that have not been conceivable before with
conventional silver technologies, and I would suggest that the independent
photographer should t least learn something about these processes, even if
they don't have access to the hardware that is required. The quality of a hard
copy digital image is not bad at the moment and is getting better all the time
(I have seen digital 10x8's that are vi ually comparable with 35mm, and in some
instances better). There is no doubt that eventually silver based photography
will disappear as we know it, and we will have to develop a new 'mind set' to
handle the new creative potential that is at our finger ips. This technology
can be used in a myriad of ways and is not just confined to the surrealistic or
Sci-Fi type image.
Global communication through the Internet allows us to reach independent
photographers on the other side of the world, to share in their thoughts,
feelings and struggles, and to view their work through the World Wide Web,
forget the hype that surrounds the 'Information Super Highway' this is a useful
tool now. Communication with fellow photographers can only broaden our outlook.
Advances are rapid and it is quite exiting wondering what is going to happen
next. There may be a divergence between the digital and the traditional
photographer with the former becoming a sort of hybrid photographer involved
more in multimedia and aud o-visual style installations, creating a new type of
art more suited to the large flat television and video screen than the gallery
wall.
So we return to where I started, in the gallery. It is difficult to imagine how
it would be possible for an individual to own a piece of multimedia art
(although someone will probably think of a way), as it is more suited to mass
access and viewing, tr ditional photographic galleries will also need to
address the opportunities presented by this new medium and the WWW. Does this
mean that in the years to come, the original fine print will become more
desirable to own? a nostalgic relic from a past tec nology, possibly.
In the final analysis it matters little what process is used to create the
image, what is important is that we use the tools that can express that vision
effectively. British Contemporary photography badly needs a jump start and one
way of doing this might be to open our minds to the changes that are happening
around us, and to have some fun while we are doing it.
This Article was originaly published in the UK Photo arts Magazine INSCAPE in
1995
Graeme Webb, ARPS
([email protected])
Graeme Webb lives in South London and is a member of London Inependant
Photography and the Royal Photographic Societies Contemporary Group, he is a
Information Systems project manager and consultant for an International
Communications Organisation. He has lectured on the New Communication
Technologies in the UK and in Europe.
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================================================================================
Note 37.02
-< Pointers on making image files for Web use >
-------------------------------------------------------------------------------1) When using a scanner, use it at values close to the final product. Since
images are going to be viewed on a monitor, scan at 72dpi. Same with colour,
if it has a 8-bit setting and you want a 8-bit result (256 colours), use
that rather than 24-bit (16 million colours).
2) Resize before reducing colours, as you can produce smoother results since
colours dither better.
3) Use as few colours as possible when working with GIFs, it makes them
smaller, this makes them faster. Using fewer colours makes the image
smaller, so pick a 16 colour logo over a 256 colour one, it could be 2-4
times smaller. Remember you want to share your images with people around the
world, not only at the same site as you. "Normal" images should be 20K or
less. That's things like logos, signatures, your cat, etc. "Artworks" can be
about 50-70K with only a few pieces per page.
4) No more than 5 images per page. This is particularly important on the
first page people go to, the welcome page or home page. Because of network
dynamics it may be slower in transferring than other pages, so please try to
keep the images few and small on this page. You don't want to bore them
before that get a chance to look at your stuff.
5) Keep your pages compatible. I have a serious pet peeve with pages that
have to have a certain browser (Netscape 1.1 or otherwise). Why? Some
Netscape 1.1 pages are broken under Netscape 1.2 beta (which I hate BTW), and
some people cannot use Netscape, they can only use what is given to them by
their access provider (e.g. Pipeline) or a Computer Centre. They might be
using a text-based browser (Try <IMG SRC="file" ALT="text">). If you want to
use Netscape 1.1 features, test to make sure they still work (not as pretty,
but work) with other browsers such as NCSA Mosaic, MacWeb, Lynx, Cello, or
Athena.
6) Normally use GIFs for inline images or 'thumbnails'. An interesting
"trick" which doesn't hurt other browsers is to use the LORES tag, i.e. <IMG
SRC="logo.gif" LORES="small_logo.jpg"> where small_logo.jpg is tiny (2K).
7) Don't bother with "Under construction" logos and notices. Changes can
happen along the way, and if you know things are broken, don't make them
available yet. Remember this is a form of self-publication. You would never
print a book with a note saying typos will be corrected in the next edition,
so why do the same thing in a web page? People also can tolerate your pages
changing/growing. Honest.
Good luck to anyone wishing to make web pages. Feel free to contact me with
any web questions if you want.
-Michael
-Michael C. Taylor, student of Mathematics at Mount Allison University
[email protected], or Box M-14 Mt. Allison University, Sackville, NB,
E0A 3C0, Canada
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================================================================================
Note 37.03
-< Further Notes on Polaroid Emulsion Transfer >-------------------------------------------------------------------------------...from Polaroid literature I have (a publication called TEST), a process
sometimes confused with Polaroid Dye Transfer is "Emulsion Transfer". It
is very esay to do. I gives you the complete emulsion of the film unlike
normal transfers so therefore the reds aren't diminished.
Anways how to do this:
1
2
3
4
5
6
7
8
9
10
11
12
Shoot a 669 Polacolor shot somehow.
Develop it normally (no silly transferring or anything yet).
Let it dry overnight (as I do) or force dry it with a hair dryer.
Spray paint the BACK of the print with clear spray paint (my choice) or
seal it with some sort of sticky masking material. This is so that the
backing doesn't dissolve. Let the paint dry if you go that route
Cut off the white border
Get a pot of H2O and heat it up to 160F. I use a meat thermometer to
check temp.
Place the image in the H2O. It'll probabally sink.
I usually leave it there for 1.5 min and then remove it. BE CAREFUL. I
don't want anyone buring themselves here. Look for the emulsion to start
to bubble up a little, that means its done.
Place the image in a tray of room temp H2O and starting with a corner,
gently lift up and peel back the emulsion. Now, I've done this and 669
emulsion is suprisingly strong. Of course, be gentle but with a little
practice, you'll get a feel for it.
Now, pay attention to which side is the front. Make sure the image is
floating face up. Try and keep it relatively spread out. Then slide your
substrate (paper, glass, whatever) underneath the image and pull them out
together. If the image is "bunched up" too much, just dip half the image
back in the water. It'll spread out. Then just turn the image 1/4 and redip. Continue until the image is how you want.
Manipulate however you see fit.
Let it dry.
Now, I've only done this with pack film. The Type 669 works spendid. The
Polacolor Pro 100 just desintegrates. These images are very sharp and have this
wonderful "fabric, silk like" quality to them. I especially like the folding of
the image at the edges. To practice, try the left over, reddish original prints
from you normal transfers.
dan - [email protected]
================================================================================
Note 37.04
-< Where to get obsolete or hard-to-find lightbulbs in US >-------------------------------------------------------------------------------[for obsolete and hard to find lightbulbs ...]
Try Bulbman in Reno Navada 1 800-648-1163.
No Minimum. Nice people too!
I found a bulb for a Sickles Duping camera @ Bulbman. This bulb had been
discontinued a number of years ago. But they had found a small manufacturer in
Japan still making it. (interesting fact , this is the same bulb that was used
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in a Norden bomb sight) I also buy all of my enlarger bulbs from these
folks. (50-75% savings over camera stores).
Shaun, Camera Graphics Photolab, Albq. NM 87106 - [email protected]
...............................................................................
The best prices for any bulbs can be had at PSC LAMPS, INC
Call them at 1 800-772-5267
Kenneth W. Zimmerman, [email protected]
...............................................................................
Why don't you try Gray Supply Co. 1-800-238-2244. They are located in East
Chicago, Indiana. They list your bulb at $20.13, but the credit card
minimum order is $25.00.
They also have flash tubes for many brands of strobe units. Also, I noticed
they list enlarger bulbs (211, 212, 213) for $2.63 each. They also list hard to
find stuff like medical and microscope bulbs.
Raymond Laue, Sr. Technical Staff, Princeton University, Department of Physics
[email protected]
================================================================================
Note 37.05
-< Where to have self-promotional postcards printed in US >------------------------------------------------------------------------------->I'd like to have postcards made for self-promotional use. Suggestions?
I found a great business in Carlsbad, CA: Modern Postcard (They do everything
via shipping, phone & fax, so you can work with them from anywhere in the US)
The price for 500 4-color postcards is $95. The price includes the scan and
color correction from your original transparency. (I sent a 4x5) They did
excellent work.
Modern Postcard
6354 Corte del Abeto, Suite E
Carlsbad, CA 92009
or call (800) 959-8365
Jeanine Birong, [email protected]
================================================================================
Note 37.06
-< Lens mount diameters / clearances for various cameras >-------------------------------------------------------------------------------Clearance diameters for various camera lens mounts. That is what is the
maximum diameter object that will fit inside/in the middle of a particular
lens mount. Contributions are boing sought!
Nikon
Pentax K
Jenaflex
above sent in by:
44.0
44.75
48.5
mm
mm
mm
Steve Morton, [email protected]
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================================================================================
Note 37.07
-< Light trap overlap designs for darkroom access >------------------------------------------------------------------------------->We are working on some remodeling of a darkroom and I'm wondering if
>anyone knows what the proper "overlap" of a U-shaped light trap should be
>for the entrance to the darkroom. Should the walls overlap each other by
>at least 1 foot, 2 feet or more? Any ideas would be appreciated.
One of the things that can tingle your craw is when someone walks through a
light trap wearing light colored clothing. Looks like the ghost of Jacob
Marley walking in. If you have the room, a light trap constructed so someone
entering is *completely out of the exterior light "before" they are visible
from inside the darkroom* will help solve the problem. A longer, wider,
whatever, light trap with plenty of overlap, or, in cases were absolutely no
light penetration can be tolerated (like in film rooms), a three-passage trap
could accomplish this.
"absolute minimum"
"better"
(avoid bright
lights placed
on this side)
exterior
___________
______
|
|
|
|
|
_______|
|
|
|
|
___|_______
|______
darkroom
(no bright
lights here)
exterior
__________________
_____
|
|
|
|
|
_______________|
| Marley
|
|
|
___|______________
|_____
ghost still
darkroom
visible from
here
THREE-PASSAGE TRAPS
with two more
walls added
outside or inside
(space permitting)
_______
extra
|
baffles -------> |
___________
|______
|