Unified color workflow

General Color & Graphics Press Calibration & Profiling
1

Hi all. This is going to be a long winded question and I apologize for that up front. If your time is limited move on and I will hope for someone who can read through it all.

I work in a commercial print shop. In 2011, we changed our workflow around with the help of Kodak and their color experts. Out goal was to become G-7 certified and to be able to create new curves as we might need.

Here is what we did. Targets were printed linear, these were read and put into a software like Curve (we purchased Curve 2 and this is what we use if we need to create new curves). This software generated our G-7 curves, which went into our workflow.

As part of the package we purchased KPS and ColorFlow (the latter was used to create profiles and DVLs that the KPS station used to create proofs to match the press (or perhaps I should say the other way around).

Anyway, we got certified back then and things worked fairly well. New owners and new management now. I am having long conversations about color management with new manager and how he sees dealing with G-7 is different than how I implemented it with the help of Kodak.

My actual question now. In ColorFlow when I create my .dvl and .icc files to use inside of KPS, based upon how Kodak helped set things up, my PCO (primary color output device condition, or target) is a printed set of targets, printed and read within ColorFlow. These were created like this. First, a set of plates were made that were linear and printed, dropped into Curve 2 to create the correct G-7 curves, replated with the curves applied and then that final set of targets is the PCO.

The question I am being asked now, is why isn’t my target merely GRACoL7 instead? I have no answer for this.

If anyone can figure out all of this and help me get a better understanding for a solid answer I would really appreciate it.

Thanks in advance and sorry for the length.

2

If I understand it properly … G7 calibration is “cheating” the proofer = simulating the behavior of the offset press inks on a proofer-printer.

“Cheating” here is ink-limiting to offset ink densities, and “quasi-linearization” to get specific (standardized) grey-scale weights and overprints.

Your machine was calibrated to follow that standard, i.e tone curve corrections were already done and should be “hidden”.

Standard test targets are usually “machine independent” - thats why the machine was calibrated for. There is no reason to print some “cheated” values, you should print a standard control target (with standard halftone values as defined in the standard).

(if I did not understood the question correctly, ask again pls.)

3

With compliant inks and paper, you should be able to qualify as a G7 master printer by simply curving your plates. This should also give you the ability to come close to certified Gracol proofing systems.

As the Gracol 2006 dataset is an averaged, smoothed, idealized dataset, you will likely be able to get a better match to your own proof if it is setup to your screening/ink/paper combination. Just make sure your proofs are in tolerance compared to the Gracol 2006 (or 2013) dataset.