Re: [csswg-drafts] [css-color-6] color-contrast() should allow specifying multiple contrast algorithms that need to be satisfied (#7357)

I'm familiar with most of this, I first got into color via your posts about this going back 3 years.

1) Let's drop anything I said about flare: that was a side point, to a side point that it doesn't make sense to look at two asymmetrical gamuts and say one is "right". I have changed my mind & believe APCA intendeds to model flare, as you describe.

2) ...to the main point that it doesn't make sense to describe WCAG 2.0 as severely broken, that's very charged language, and _from your perspective_, I agree. having that perspective is what motivates one to work on problems like this. 

However, once other people, in a more formal setting, justify that perspective via a couple people with standard color vision noticing that magnitude of luminance difference is different from magnitude of color difference...that's...not good. At all.

3) L* stuff combats a claim that isn't being made. I, nor anyone else, claims that the delta L* required for a constant value for contrast with a given L* x is itself a constant value. I think you're seeing L*, or delta L*, and assume I'm proposing yet another contrast algorithm that uses delta L*. No. 

My claim:
- The contrast algorithms we've seen, whether WCAG 2.1 or APCA, take two Ys as input
- Y and L* are the same physical quantity. They are pure functions of eachother. They can be converted to and from eachother with no other inputs.
- Thus, given a L* and contrast measure, we can find the L* that contrasts 
- Given that, the L* and the L* needed for contrast, we can calculate delta L* required for contrast

I'm very surprised this wouldn't be embraced, given how beneficial it is for designers who must work with these algorithms.
With that, it becomes trivial to understand what range of colors contrasts with a given color, as well as trivial to alter a color to meet contrast via L*a*b*/LCH/HCT.

-- 
GitHub Notification of comment by jpohhhh
Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/7357#issuecomment-1181907072 using your GitHub account


-- 
Sent via github-notify-ml as configured in https://github.com/w3c/github-notify-ml-config

Received on Tuesday, 12 July 2022 15:26:29 UTC