Originally Posted by zoyd
All the dE calculations are absolute using the fixed CIE points. The grayscale does not include luminance but everything else does. The saturation offsets need to know the luminance at 100% saturation because the x,y locations below 100% saturation depend on gamma (which means luminance) and this is calculated assuming gamma = 2.22. So if you have a display which does not have gamma=2.22 the saturation offsets will have a small error in them.
You really only need to set clipping at about 240 or so since there is little if any information content above 235 in source material. Regarding the 5% points this is very display dependent on how it handles the 10pt control, typically you can smooth it out a bit by adjusting the straddling points so they are not quite right, but I've not found this to be of real value. I mean in the end I could not see any visual difference in the results. The grayscale dE just noticeable difference (JND) is 2.3 so you shouldn't notice anything under 3.
But if I choose "Measure, Saturation, All Colors", HCFR also ask for 100% saturation for all colors, which means it shouldn't produce dE in the thousands... I got like 7000+ dE in each color..
It's fixed by measuring the Primary & Secondary colors sweep after that.
Btw, after measuring all colors saturation, sometimes the RGB Levels didn't change to Luminance in the measurement tab. The 75% will correctly shows Luminance, but the 100% or 50% still shows RGB Levels.. Maybe it's because of that?
And I kinda forgot, but I don't think the all colors saturation sweep ask for 100% white, only the primary & secondary color sweep ask for it.. Is it not necessary in the all colors saturation sweep?
Well.. My set is kinda strange..
THX mode, 100 contrast, clips at 240.
Pro mode, 100 contrast, clips at 244.
But 100 contrast makes the high-end RBG Levels hard to balance out, especially in the in between 5%.. Almost impossible getting below 3 dE really..
Tried 55 contrast, the high-end RGB Levels are easily balanced out..
It seems the lower the contrast, the easier it is to balance out the high-end RGB Levels...
Thanks for the tip!
I managed to get average dE of 1.12 using 20pt white check; with max dE of 2.2.. Which is below 2.3
Of course, the higher than 85% gamma are a bit wonky.. But it's a lot better than before..