GTLab 2015
How to tackle OBA? Practical solutions
for proof to printing matches for OBA
rich substrates
Dr. Andreas Kraushaar | [email protected]
1
GTLab 2015
Agenda
1.What is (was) the problem?
2.New measurement devices (M1, as D50)
3.New viewing cabinets (M1, as D50)
4.“Measure as you see” works & FOGRA51 is ready
5.How to measure OBA?
6.Paper properties
7.Summary
Source: GMG
Dr. Andreas Kraushaar | [email protected]
2
GTLab 2015
1. Problem(s)
Printing substrates uses a lot of
optical brightener agents (OBA)
¬ colour communication
depends on D50 + UV-level
¬ Differences in UV & OBA
amount compromises
consistent (predictable)
colour appearance/
communication
Dr. Andreas Kraushaar | [email protected]
3
GTLab 2015
2. Important improvements
Measurement condition M1 (ISO 13655:2009)
¬ Simulates D50 much closer in the UV-range
¬ Used measurement light source become more
consistent among vendors
¬ Current M1 capable devices (45°/0°)
Dr. Andreas Kraushaar | [email protected]
4
GTLab 2015
3. Important improvements
Measurement condition M1 (ISO 3664:2009)
¬ Simulates D50 much closer in the UV-range
¬ Used viewing cabinets light source become more
consistent among vendors
Dr. Andreas Kraushaar | [email protected]
5
GTLab 2015
4. How to measure UV?
A 69-year-old man presented with a 25-year history of gradual, asymptomatic thickening
and wrinkling of the skin on the left side of his face. …The patient reported that he had
driven a delivery truck for 28 years. Ultraviolet A (UVA) rays transmit through window
glass, ….
UV-­‐poor
Dr. Andreas Kraushaar | [email protected]
UV-­‐rich
http://www.nejm.org/doi/full/10.1056/NEJMicm1104059
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GTLab 2015
4. D50 with UV or without (UVCut)?
¬ CIE defined the daylight illuminant series D
¬ From this illuminant series D, several daylight temperature
versions have derived: D50, D55, D65, …
¬ For many years, ISO 3664 describes D50 to be the reference and
best compromise for viewing
¬ … including its UV-content
Source: GMG
Dr. Andreas Kraushaar | [email protected]
7
GTLab 2015
4. Fogra method: Concept
¬ Measure ambient light source
¬ Use MS-Excel or software
Dr. Andreas Kraushaar | [email protected]
8
GTLab 2015
4. Fogra method. How it works
Light measured at Fogra lab 66%
Dr. Andreas Kraushaar | [email protected]
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GTLab 2015
4. Normlight (old)
¬ With the revised 3664 (2009) we get more UV in the light from the
normlight bulbs
old
normlight from Just
old proof
Dr. Andreas Kraushaar | [email protected]
printing paper
Source: GMG
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GTLab 2015
4. Normlight: Up to date
¬ With the revised 3664 (2009) we get more UV in the light from the
normlight bulbs
new
normlight from Just
old proof
Dr. Andreas Kraushaar | [email protected]
printing paper
Source: GMG
11
GTLab 2015
4. Normlight: Up to date
¬ With the revised 3664 (2009) we get more UV in the light from the
normlight bulbs
new
normlight from Just
new proof
Dr. Andreas Kraushaar | [email protected]
printing paper
Source: GMG
12
GTLab 2015
4. Normlight: Up to date
¬ With the revised 3664 (2009) we get more UV in the light from the
normlight bulbs
old
normlight from Just
new proof
Dr. Andreas Kraushaar | [email protected]
printing paper
Source: GMG
13
GTLab 2015
5. How to measure OBA?
¬ Practical measure: White degree, Difference of the CIEb*-Values when
measuring with and without UV excitation (ISO 13655:2009 M1 and M2)
¬ „∆B", meaning the difference between ISO Brightness (ISO 2470-2) and
ISO Brightness without UV excitation (UV-Cut at 410 nm)
∆B
OBA amount
<1
no OBA
<= 4
faint
<= 8
low
<= 14
moderate
> 14
high
Sheet Fed
Dr. Andreas Kraushaar | [email protected]
Source: X-­‐Rite
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GTLab 2015
5. How to measure OBA?
¬ Use ∆B (when device supports it) or two colour measurements
¬ Either: M1 and M2 (new devices) or M0 and M2 (legacy devices)
Example:
M1: 95 2,1 -­‐8,1 M2: 94 1,5 -­‐1 ∆CIEb*= 7,1 ∆B=16 High OBA amount Dr. Andreas Kraushaar | [email protected]
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GTLab 2015
5. Fogra provides the OBA amount online
Fogra certified proofing papers are listed with the ∆B amount
Dr. Andreas Kraushaar | [email protected]
16
GTLab 2015
6. Paper properties
Important for colour management: Colour and OBA level
uncoated papers
coated papers
Source: GMG
Dr. Andreas Kraushaar | [email protected]
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GTLab 2015
6. Practical implementation
¬ Gamut differences for proof matching
¬ Wire frame: OBArich coated stock
¬ Solid: OBA poor proofing stock (EPSON 9900)
Dr. Andreas Kraushaar | [email protected]
18
GTLab 2015
6. Checking “paper gamuts”
¬ OBArich papers exceed the gamut of OBAfree proofing paper
¬ Use the diagram to check out “proofability”
OBAfree proofing stock gamut
OBArich proofing stock gamut
Source: GMG
Dr. Andreas Kraushaar | [email protected]
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GTLab 2015
6. OBArich substrates can be lightfast
¬ Inkjet prints with different OBA level suntester
¬ There are light fast proofing papers with high OBA levels
24h exposure (solids)
Selection
of inkjet s
ubstrates
sorted by
(printed o
∆B
n EP4880
)
Dr. Andreas Kraushaar | [email protected]
20
GTLab 2015
6. ISO 12647-2 - Characterization Data Sets
¬ FOGRA51 reflects offset printing for the new PC1 data set
(FOGRA52beta for PC5)
¬ FOGRA51 will be released in summer 2015
¬ Proof to print matches performed on OBArich proofing stock
¬ Practical tools (bb-values, GrayCon etc) are coming soon
¬ Read more at Fred15 - http://www.eci.org/en/projects/fred15
Dr. Andreas Kraushaar | [email protected]
21
GTLab 2015
7. Summary
¬ New measurement modes M1 and ISO 3664:2009 compliant viewing
conditions allow for a predictable colour communication (including
measurement traceability to NIST (e.g. XRGA)
¬ Some tools needs to be provided (e.g. proofing systems using
OBArich stock)
¬ Old viewing / measurement conditions might cause inconsistencies
Update now
¬ Retrofits (new lamps with UVcut lenses) contradict the colour
communication since it does not excite the printed matter as seen by
the print buyer. Contact an expert to assist you during the transition
phase.
Dr. Andreas Kraushaar | [email protected]
22
GTLab 2015
PSD certified …
Dr. Andreas Kraushaar | [email protected]
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