Re: [Lcms-user] css-color-hdr and HDR eotfs (Jzazbz and ICtCp)

[Wolthera <gri...@gm...>]

Ok, I found the answer to my own question(s): Not yet.

All of these are being discussed on whether they'll become extensions
to ICC4 & Max:
http://www.color.org/groups/hdr/index.xalter

This also includes recommended ways of handling NCLX colorspace descriptions,
for those of us that are trying to figure out the mysteries of heif and avif.

Hope this helps,

On Wed, Feb 10, 2021 at 3:41 PM Wolthera <gri...@gm...> wrote:
>
> hey,
>
> I was reading the css-color-hdr draft [1], and it contains a few
> unusual colorspaces.
>
> Now, as far as I understand it, the only way to have an ICC spec
> conformant icc profile for Rec 2100 is by using LUTs, because the PQ
> and HLG eotfs cannot be described by the formulas in the ICC specs
> [2]. But at the least it is possible.
>
> But the draft also specifies a Jzazbz colorspace (which seems to be
> L*a*b*, except L* is replaced with the PQ-encoded Jz) as well as ICtCp
> [3].
>
> Is it possible to have icc profiles, or a littleCMS workflow for
> these? I'm not too familiar with the icc profile spec, so I don't know
> what the exact rules are for these big encompassing colorspaces, and I
> think it'd be valuable for W3C to have the feedback if these
> colorspaces are not possible for a variety of open source software.
>
> [1] - https://drafts.csswg.org/css-color-hdr/
> [2] - https://github.com/mm2/Little-CMS/issues/217
> [3] - https://en.wikipedia.org/wiki/ICtCp
> --
> Wolthera



-- 
Wolthera