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Re: Color Contrast and Transparency | WCAG 2.1

From: Eric Eggert <ee@w3.org>
Date: Thu, 28 Jul 2016 21:07:10 +0200
To: "John Foliot" <john.foliot@deque.com>
Cc: WCAG <w3c-wai-gl@w3.org>, "W3C WAI Accessible Platform Architectures" <public-apa@w3.org>
Message-ID: <6D657B4C-BF32-4F32-B3B7-14F1542BEA1C@w3.org>
On 28 Jul 2016, at 19:12, John Foliot wrote:

> Hi.
> A question/comment for the Working Group: have we contemplated changes 
> (in
> any of SC, Understanding or Techniques) that addresses the impact of 
> Alpha
> Transparency of colors and the impact on color contrast and 
> accessibility?
> Has any of the 3 current Task Forces covered this in any fashion?
> As part of an Action Item[\*] I have at the APA, I have been asked to 
> reach
> out to WCAG WG as there is a recognized need for techniques to measure
> color contrast with alpha layer related to
> https://www.w3.org/tr/css-color-4/ css color module level 4

Just skimmed the document and found this contrast CSS function which has 
a related luminance computation – this might be interesting to see how 
that works with the WCAG 2.0 definition. I think alpha transparency 
would be really good to cover in 2.1…


> If none of the TF's have looked at this to date, Andrew & Josh can we 
> get
> this logged as an action item for the WCAG WG? As well, if we have any
> questions or concerns around any of this, we (APA) already have some 
> time
> blocked out at TPAC with the CSS WG, and that would be the time to 
> bring
> forward those issues. Hoping to flesh this out between this week and
> September.
> Cheers!
> JF
> [\* https://www.w3.org/WAI/APA/track/actions/2066 - link may not be 
> open to
> all to see, but the gist of the issue is covered in this email.]
> -- 
> John Foliot
> Principal Accessibility Strategist
> Deque Systems Inc.
> john.foliot@deque.com
> Advancing the mission of digital accessibility and inclusion


Eric Eggert
Web Accessibility Specialist
Web Accessibility Initiative (WAI) at World Wide Web Consortium (W3C)
Received on Thursday, 28 July 2016 19:07:23 UTC

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