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Hi Florian,
When creating a 3dlut for a colour space that is bigger than the tv gamut (eg my tv in wide mode covers 85% of p3), is it better to use something like relative colorimetric or is absolute with white point scaling still preferred?
The only difference between relative vs absolute colorimetric is that the latter reproduces the source whitepoint (i.e. D65). If you want gamut compression, use perceptual (or perhaps saturation) intent.
I was just thinking if the source gamut is much larger than what the TV can reproduce, maybe I should use something other than absolute? Would perceptual be a better choice in this situation?
Thanks!
I’m no expert on this, but AFAIK, it depends on what you want to achieve:
absolute: try to make every color as absolutely correct as possible, including white when whitepoint scaling – technically best, but may cost a lot of brightness/contrast to achieve whitepoint etc.
if your display already has the correct whitepoint, relative would be same as well
perceptual would squash all the theoretical colors into the smaller subarea your TV can display, thereby shifting/changing them and making them (more) incorrect.
I always use the default abs+wp, because I want to only see “correct” colors, everything else should not be visible at all. Also I think much of DCI (and even more so BT2020) is unused and probably will never be used extensively, i.e. 85% DCI is very good already. It’s like HDR in UHD BluRay with it’s theoretical 10000nit brightless level – no movie uses more than 1000nit and most are below 500nit 99% of the movie ;), i.e. 95% of the HDR brightness space is unused 99% of the time and 90% is not used at all and probably will never be used extensively.
My thinking was, with absolute if the TV gamut is much smaller than the source gamut, using absolute will mean a lot of colors will get clipped. Even though perceptual will not technically give you 100% correct colors, it may be a better choice for this (the displaycal help pages say as much, although doesn’t say which is more ‘ideal’ for this scenario)
