AW: 48-Hour Call for Consensus (CfC): CSS Filters Comment Request

+1

Gottfried 

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Von: Janina Sajka [mailto:janina@rednote.net] 
Gesendet: Mittwoch, 12. Dezember 2018 23:25
An: Accessible Platform Architectures Administration <public-apa-admin@w3.org>
Betreff: 48-Hour Call for Consensus (CfC): CSS Filters Comment Request

Colleagues:

This is a Call for Consensus (CfC) to the Accessible Platform Architectures (APA) Working Group on a proposed Accessibility Considerations Section request to the CSS Working Group.

**Suggested Comment**

 The Accessible Platform Architectures (APA) Working Group requests addition of the following section to the specification Filter Effects Module Level 1 https://www.w3.org/TR/filter-effects-1/ <https://www.w3.org/TR/filter-effects-1/>

Accessibility Considerations Statement 

In addition to standard WCAG 2.1 requirements for images, content authors using filter effects should be mindful of how the filters modify the colors, contrast, size, and animation of images.  The following Level A and AA success criteria could be affected:

*Success Criterion 1.4.1 Use of Color (https://www.w3.org/TR/WCAG21/#use-of-color <https://www.w3.org/TR/WCAG21/#use-of-color>). Given a button shaped as an arrow with the text, “next,” a filter could modify the background color so that the text is no longer visible. 
*Success Criterion 1.4.3 Contrast (minimum) https://www.w3.org/TR/WCAG21/#contrast-minimum <https://www.w3.org/TR/WCAG21/#contrast-minimum>). Given the example above, a filter could modify the background or text color(s) so  color contrast requirement is not longer met.  
*Success Criterion 1.4.11 - Non-text Contrast (https://www.w3.org/TR/WCAG21/#non-text-contrast <https://www.w3.org/TR/WCAG21/#non-text-contrast>). Given the example above, a filter could modify the colors so that the contrast between the text and button color, and/or the button color and background no longer meet color contrast requirements. 
    It is particularly important to be mindful of color contrast  requirements when a transparency is present because automated measurement is not available to quantitatively and correctly judge whether sufficient contrast is being provided, thus requiring application of informed human judgement on a case by case basis.
*Success Criterion 2.3.1 Three Flashes or Below Threshold (https://www.w3.org/TR/WCAG21/#three-flashes-or-below-threshold <https://www.w3.org/TR/WCAG21/#three-flashes-or-below-threshold>)  Beware of any filters that add animation that may add or change the flash rate. 

*       ACTION TO TAKE

This CfC is now open for objection, comment, as well as statements of support via email. Silence will be interpreted as support, though messages of support are certainly welcome.

If you object to this proposed action, or have comments concerning this proposal, please respond by replying on list to this message no later than 23:59 (Midnight) Boston Time, Monday 17 December.

NOTE: This Call for Consensus is being conducted in accordance with the APA Decision Policy published at:

http://www.w3.org/WAI/APA/decision-policy

Thanks to Becky Gibson for drafting this comment.
http://lists.w3.org/Archives/Public/public-apa/2018Dec/0010.html


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Janina Sajka

Linux Foundation Fellow
Executive Chair, Accessibility Workgroup: http://a11y.org

The World Wide Web Consortium (W3C), Web Accessibility Initiative (WAI)
Chair, Accessible Platform Architectures http://www.w3.org/wai/apa

Received on Thursday, 13 December 2018 05:44:42 UTC