Re: [csswg-drafts] [css-color] Should whitepoint and other canonical values be listed in the code section? (#6618)

Hi @facelessuser 

> ...._What's the point of stating the standard of the white point that should be used if the examples don't even bother using It 🤷🏻? I believe this is unintentional, but it probably should be cleared up. The 5 decimal sRGB transform should be something more like: ...SNIP_

Yes, this is what I was mentioning above, that the pre-calculated matrix for sRGB is using the 0.3127, 0.329 values. And herein lies the rub: Some standards such as ICC are a little different from, say, the CIE. And both ICC and CIE have differences over time and release versions, compounded by other parties using their own in-house standards.

For instance, the 2004 third edition of CIE Colorimetry specifies the xy for D65 as 0.31272, 0.32903 

At some point before that (1978?), the CIE for D65 was 0.3128, 0.3292 

_And_ I distinctly remember seeing it _often_ as 0.313, 0.329 in the late 90s and early 2000s.


> _This goes for all the transforms. Since I'm aware of how to get the calculations, I'm not concerned with not being consistent across conversions,_ **I'm more concerned with what is the actual spec**, _and is everyone going to implement it differently? If the spec doesn't even use it the same throughout, what hope is there for anyone else 🙂 ?_

Well, today, the CIE says D65 is 0.31272, 0.32903 — but again there are still plenty of lingering legacy versions everywhere. And those need to be for compatibility with some apps and old content etc.

I think the code samples in CSS4 are intended as "examples" only and not as normative, and in fact says just that:

> ### _Sample code for color conversions_
> _This section is not normative._
>   _`   // Conversion can also be done using ICC profiles and a Color Management System `_

And in fact probably can't be normative or require the use of one spec, as there could be unintended consequences such as for legacy content, etc.

My initial post was not meant to say "this should be the absolute standard" so much as to ask "should we be consistent and also provide a canonical touch stone using the latest standard values" etc.


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Received on Monday, 20 September 2021 06:35:41 UTC