Originally Posted by anta1974
Why do not you add patterns for chromapure for calibration 75 luma/ 75 saturation for gamma=2.35 and gamma=2.4 and gamma=2.25 and gamma=2.30?
ChromaPure's Color Engine Calculations are based to 2.22 Gamma, that's why I'm using 2.22 note above to my all ChromaPure chapters i'm using to my calibration disk.
This affects only Color Gamut / Saturation / Color Checker measurements only, not the Grayscale.
Before 3 years when I was CalMAN 5.0.0 beta tester, the first versions had the same issue, the RGB Triplets for any single Color Gamut / Saturation pathes were not fixed and were moving when you was changing the Target Gamma Value from 2.2 to any other value.
To solve this for my calibration I was using an unreleased in public version of my calibration disk (2011) where I had different chapter patterns for every users's entered Gamma value, like these chapters below.
But this was making so difficult to give compatibility to external pattern generators (without full RGB Triplet Support) or Calibrations disk to follow with so many chapter for every possible entered gamma value so later CalMAN's developement team decided to use a fixed RGB Triplet for all Color Gamut / Saturation / Color Checker patches but move the Targets of every xyY upon any entered gamma value. So the Patterns were the same, just the CalMAN's calculations were re-directed to different xyY targers.
For any future version of Ted's LightSpace CMS Calibration Disk, I have no plans to add all these possible gamma values chapters for ChromaPure users.
It's a better idea to ask from Tom from ChromaPure to add dropdown menu in ChromaPure settings where the user will be able to select the ChromaPure's Engine Gamma Value Calculations to re-direct/move the xyY targets uppon any selected gamma value so the patterns will be the same just the calculations will be changed only.
But the differencies in dE are not so great to be noticed.
If you like you can use the ColorChecker of my disk (which is based to Gamma 2.22) of ChromaPure and take the measurements with 2.22 Gamma selected in ChromaPure and later re-measure with 2.30 or 2.35 gamma selected, and post here or to ChromaPure's thread the ColorChecker dE Reports to show the differencies.