- What exactly is the difference between ISO 1247-2 and GRACol/SWOP data files?
The ISO provides an international standard. Some national organisations
provides material (reference data, reference-prints, control strips
etc.) according the ISO 12647-2.
You can buy the ISO 12647-2 via iso.org or national resellers.
Reading the ISO 12647-2, you will find differences between a positice
platemakin process (mainly used in EUROPE) and negative platemaking
process (mainly used in the USA)
negative platemaking-process results to an higher TVI compared to
- Where can you get these reference files and/or how do you determine the ideal TVI curve for your presses.
In Germany, the federal associations of printers produced a lot of
material helping printeres and prepress standardizing their processes
according ISO 12647-2 / positive platemaking process.
At altonatestsuite.com you get:
- Reference-prints for 5 different papertypes according ISO 12647-2
- The data, which was printed
- Characterization-data and profiles
- The TVI curves in 5% steps for every papertype
- A manual in german and english language
A free reference-file for coated-paper and free profiles and
characterization-data for all papertypes according ISO-12647-2 positive
platemaking is available at eci.org
For the USA GRAcOL delivers materials for working according ISO 12647-2
(negative platemaking process).
SWOP / TR 001 represents papertype 3 according ISO 12647-2
CGATS / TR 004 represents papertype 1/2 according ISO 12647-2
I dont know, if somebody is deliviring a free profile for TR 004. (at
profile central ???)
But if, you have a profiling software, you can download the
characterization-data at cgats.org
There you can also buy reference-data and prints.
- Should the dot gain I read from my inkjet ideally read the same as the press. Right now, I have my inkjets calibrated toward a GRACol reference, but the yellow dot gain from the inkjet reads 5% below the cyan and mag, yet the gray balance looks good on the proofs.
If you want to control your proof, you should do this with an spectro
photometer reading Lab-values and comparing the results with a
reference- based on profile (e.g. SWOP or TR004)
Dotgain and density is not working for evaluating digital proofs,
because the technology is completly different to offset-printing. (E.G.
pure offset-colors are always represented by mixed colors on a proper
calibrated and profiled proofing systems)
- Should I worry about using the Murray-Davies verses Yule-Nielson formula which according to an XRite manual tries to adjust dot gain for the type of paper being printed on.
As measuring density or dotgain makes no sense on a digital proof, both
formulas are not important for evaluating a digital proof.
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