- From: Pekka Paalanen via GitHub <sysbot+gh@w3.org>
- Date: Mon, 09 Sep 2024 11:13:55 +0000
- To: public-css-archive@w3.org
I'm on the same track as @swick here. For human perception, (absolute) luminance is relative to its viewing environment. As an extreme example of environment dependency, any PQ encoded image displayed on a usual consumer PQ display will be destroyed when the display is brought into bright daylight without any adaptation. One has to choose whether to preserve the image appearance as graded (for some value of "preserve"), or fix the presentation luminance of the signal. These two goals agree only under the reference viewing environment, and disagree otherwise. One could of course say that all viewers must adapt their environments so that displaying an image nit-for-nit becomes appropriate, but I think that does not generalize very well outside of living rooms and theaters. The above does not consider the physical limitations of a real display. Those limitations may forbid a sufficient adaptation to the environment. I believe the term "absolute" in this context refers to a unit that is not relative to some maximum at hand (e.g. display peak luminance) but is relative to some global constant (e.g. reference viewing environment brightness). Why is the white level of sRGB merely 80 cd/m² while PQ (and HLG on a 1000 cd/m² peak display) has 203 cd/m²? Where does this brightness creep come from? -- GitHub Notification of comment by ppaalanen Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/10460#issuecomment-2337829878 using your GitHub account -- Sent via github-notify-ml as configured in https://github.com/w3c/github-notify-ml-config
Received on Monday, 9 September 2024 11:13:55 UTC