Re: [csswg-drafts] Powerless a,b and chroma for Lightness >= 100% (#7924) from Chris Lilley via GitHub on 2022-10-20 (public-css-archive@w3.org from October 2022)

From: Chris Lilley via GitHub <sysbot+gh@w3.org>
Date: Thu, 20 Oct 2022 16:14:29 +0000
To: public-css-archive@w3.org
Message-ID: <issue_comment.created-1285821952-1666282467-sysbot+gh@w3.org>

Crucially, the L axis in hdr-CIELAB uses a modified equation compared to CIE Lab:

![image](https://user-images.githubusercontent.com/2506926/197002336-6433d075-c14a-43ed-93a1-90a264c5ac60.png)

It isn't just "extending the range to 400".

The above is equation 23 from 

M.D. Fairchild and P.-H. Chen, "Brightness, lightness, and specifying color in high-dynamic-range scenes and images," _SPIE/IS&T Electronic Imaging Conference,_ San Francisco, 78670O-1 -78670O-14 (2011). [full text PDF](http://markfairchild.org/PDFs/PRO37.pdf)


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Received on Thursday, 20 October 2022 16:14:31 UTC