Originally Posted by pisymbol
Should I start at 75% and go back, or start from 0% and go forward, or does it even matter?
Not sure I understand your question. Unlike Grayscale, with color, you only have one CMS control for each color, so you have no individual control to match luminance and chromaticity for each saturation value of a color.
So your options are to either:
1) Select a specific saturation value (typically 100% or 75%) of a color, and use the CMS controls to minimize dE for that color by matching chromaticity and luminance as well as possible
2) Perform a saturation sweep (25 - 100% saturation) for a given color. Then tweak the CMS control for that color with a view to minimizing dE for 25-75% saturations as a whole rather than targeting the dE for a specific saturation target. This may require compromises on accuracy of 100% saturation reading or even across all saturation targets in order to achieve an overall lower dE across the 25-75% saturation targets.
If you are doing option 1, then you don't need to even do saturation sweeps for the tweaking/calibration. Looks like you have 75% selected, so just use the relevant patches when doing your primary/secondary measurements and minimize dE accordingly. Btw, does AVS709 have 75% Saturation, 75% Luminance patterns? AFAIK
, the 75% color patterns are 75% saturation at 100% luminance?
If you are doing option 2, then make a full sweep measurement first. Then examine the CIE chart and the % luminance target values in the table and determine the next iteration of hue, saturation and luminance (brightness) tweaks to apply for that color. Make small increments, then redo the sweep. Note if you made improvements and try to minimize average dE across 25-75% saturation targets.