Forensi-Tech Limited
Box 40007 Bank & Hunt Club - Ottawa, ON, Canada - K1V 0W8
Phone: (613) 737-5200 Toll-Free: (866) 860-8179 Fax: (613) 521-2512
E-mail: [email protected] Website: www.forensi-tech.com
Technical
Basic YellowNote
40
Introduction
Basic Yellow 40 (Maxilon Flavine 10GFF) is a highly fluorescent dye stain which stains cyanoacrylatedeveloped latent prints. When illuminated with an ultraviolet lamp or Forensic Light Source, latent prints
fluoresce brightly, and weakly-developed latent prints that could not be seen under normal viewing
conditions may be easily seen and photographed. Basic Yellow 40 is very sensitive to ultraviolet light and
can be used with a simple long-wavelength ultraviolet lamp. It is often used by police agencies that cannot
afford to purchase a more expensive Forensic Light Source.
Safety
As with all chemicals, always read the MSDS (material safety data sheet) to learn about the safe
handling and health hazards of each chemical. With Basic Yellow 40, it is recommended that rubber
gloves and safety glasses be worn. When combined with any of the solvents listed below, the solution
should be mixed and used in a fume hood. When examining the evidence with a light source, wear
protective goggles. Be familiar with the light source and know which goggles to wear under all
circumstances.
Mixing Instructions
Basic Yellow 40 is a yellow powder that needs to be dissolved before using. The simplest dilution is 2%
Basic Yellow 40 in reagent alcohol. In other words, 2 grams of Basic Yellow 40 in 1000 ml of reagent
alcohol. This dilution can be adjusted to make it stronger (add another 1 to 2 grams of Basic Yellow 40) or
to make it weaker (only add 1 gram of Basic Yellow 40 to 1000 ml of reagent alcohol).
Glue Fuming
Before using a solution of Basic Yellow 40, it is necessary to glue-fume the piece of evidence. It is recommended to underfume rather than overfume. If heavy white residue is present on the background surface or
heavy white latent prints are developed, the Basic Yellow 40 may stain the entire surface and the latent
prints will appear as bright glowing globs with no ridge detail when illuminated with a light source. The
use of fast-acting, chemical catalysts or accelerator pads is not recommended, as the process can develop
heavy, white residue before the reaction can be stopped.
Place a few drops of liquid glue or a Hard Evidence™ Pouch in a closed container, such as a fish tank, with
the evidence and a cup of warm water. Allow the evidence to remain about ten minutes before checking. To
check the progress of the fuming without opening the lid of the fish tank, place a black latent print backing
card in the tank with test prints on it. When these test prints are just becoming visible, remove the evidence
from the tank to stop the process.
Fuming under vacuum with a Coleman Vacu-Print ™ will help to eliminate the problems associated with
overfuming. Vacuum technology for glue fuming is relatively new. This method will develop latent prints
without excessive residue coating the surface of the evidence, and it will be easier to handle the evidence.
Because there is no residue buildup on the evidence, dye-staining for fluorescent examination is more
effective. Dyes such as Basic Yellow 40, Rhodamine 6G and Ardrox adhere to the glue residue on the item.
When there is excessive buildup of the glue residue, the dye stains all of it, causing the entire surface to
fluoresce, perhaps obscuring ridge detail.
Forensi-Tech Limited.
Page 1 of 3
1-866-860-8179
With a vacuum process, items of evidence, such as garbage bags do not have to be opened up. The fumes
will coat all of the surfaces. Also, items such as soda cans, screwdrivers and handguns can be placed inside
the chamber with the items touching each other. It is not necessary to leave space between each item. For
additional information on the Coleman Vacu-Print ™ vacuum fuming chamber and glue fuming processes,
request the free Technical Note 1-4502.
Application
In a fume hood, apply the Basic Yellow 40 solution by submerging the evidence in a tray or container.
“Washing” the solution over the surface using a chemical wash bottle can also be done. Catch the runoff
solution in a clean tray and use it again. DO NOT SPRAY THIS SOLUTION. Leave the solution on the
surface for about one minute. Then, rinse the item with running tap water. Allow the item to air-dry before
examining with a light source.
Because some surfaces may absorb reagent alcohol, it is recommended to test a small section of the surface
first with the Basic Yellow 40 solution. If that section totally fluoresces after rinsing and drying, the alcohol
has absorbed in the surface and will cause the entire object to fluoresce if treated with this solution.
Examination
Dim the room lights and shine the light from the Forensic Light Source or ultraviolet lamp over the surface
of the object. A long-wavelength ultraviolet lamp with a moderate to high intensity output can be used
effectively to illuminate latent prints developed with Basic Yellow 40. Photograph the visualized latent
prints.
For those using a variable wavelength Forensic Light Source, examine the evidence using 450 to 480 nm
wavelength of light and view with orange goggles. Also examine the evidence with 365 nm wavelength of
light and view with clear goggles.
Photography
To photograph the fluorescent-developed latent prints, duplicate the arrangement by which the best contrast
was viewed with the eye. Include a fluorescent scale in the photograph next to the evidence. Use the
wavelength, the color of the viewing goggles and the angle of the light source to obtain the best photograph. Using a fine-grain black and white film with a medium ƒ-stop (ƒ/8 or ƒ/11) will give a photograph
showing highly defined ridge details. The ridges of the latent print will be white and the background will be
dark in the resulting photograph.
To reverse the color of fluorescent-developed latent prints, take the photographs using slide film, such as
Polaroid PolaPan, to see the results in just a few minutes. Print the slide film on regular black and white
photo paper to see the ridges dark and the background light. For additional information on photography of
fluorescent latent prints, see page 22.
Additional Reading
Advances in Fingerprint Technology edited by Dr. Henry Lee and Dr. R. E. Gaensslen
Friction Ridge Skin: Comparison and Identification of Fingerprints by James F. Cowger
Manual of Fingerprint Development Techniques by the British Home Office, second edition
Fingerprint Detection by Fluorescence Examination by the British Home Office
Ordering Information
Catalog No. 1-0044 .......... Basic Yellow 40, 25 grams
Catalog No. 6-3847 .......... Adhesive Fluorescent Scales, 2 in—50 mm, pack of 50
Catalog No. 6-3816 .......... 6 inch Fluorescent Scales, cardstock, pack of 10
Catalog No. 6-3885 .......... INCH "L" Shaped Scale, Fluorescent, cardstock, pack of 5
Catalog No. 8-5008 .......... COWGER/Friction Ridge Skin
Catalog No. 8-5015 .......... HOME OFFICE/Manual of Fingerprint Development Techniques, 2ND edition
Catalog No. 8-5039 .......... HOME OFFICE/Fingerprint Detection by Fluorescence Examination
Catalog No. 8-5041 .......... LEE/Advances in Fingerprint Technology
Forensi-Tech Limited.
Page 2 of 3
1-866-860-8179
Please Note
The goal of latent print examiners and technicians is to discover and collect latent prints by various means.
The ultimate goal is to identify those latent prints to the person responsible for the criminal act and prosecute them to the fullest extent of the law. Some of these means to develop latent prints include processing
evidence and other surfaces using powders, chemicals and lighting techniques. The purpose of this booklet
is to provide a resource of information about latent print processing techniques. This booklet does not
contain every process available and does not claim to be all inclusive of all variations of processes. The
information has been collected from various sources.
Caution
This booklet contains descriptions of processes utilizing chemicals or combinations of chemicals which
may be hazardous to the user’s health. It is strongly recommended that proper precautions be taken when
using hazardous chemicals or combinations thereof. Safety equipment needed may include fume hoods,
gloves, protective clothing, safety goggles, splash shields or respirators. It may be necessary to store these
chemicals in specific containers or cabinets. It is the user’s responsibility to know and use the proper and
adequate safety equipment required for the various chemicals listed.
Disclaimer
FORENSI-TECH LIMITED assumes no responsibility for the use or misuse of any of the chemicals,
procedures, methods or ideas described herein resulting in injury and/or damage to persons or property.
Forensi-Tech Limited.
Page 3 of 3
1-866-860-8179