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Re: Color Contrast in charts and graphs

From: Alastair Campbell <acampbell@nomensa.com>
Date: Wed, 16 Nov 2016 22:33:50 +0000
To: Scott McCormack <scott.mccormack@ssbbartgroup.com>, "public-low-vision-a11y-tf@w3.org" <public-low-vision-a11y-tf@w3.org>
Message-ID: <HE1PR0901MB1466D05127EC63A8FB145FF3B9BE0@HE1PR0901MB1466.eurprd09.prod.outlook.com>
Hi Scott,

I think the Information Graphic Contrast SC has those covered, even apart from using colour-alone to label meaning (so they fail current WCAG 2.0), the contrast is terrible and would be caught by the new SC.

For your list:
- Color contrast requirements have to apply to informational graphics (like charts and graphs) as well as text while exempting pictorial graphics

Yep, it is requiring 4.5:1 for graphics to contrast against each other (if they are needed for understanding), or 3:1 if they are more than 3px wide.

- Color contrast must be sufficient so that all elements in an informational graphic can be distinguished individually
- Color contrast must be sufficient so that adjacent items can be distinguished from one another.

Yes, either with contrast between elements, or borders that contrast against each element, or by labels & alternatives.

Have you had a chance to read through the SC?
https://www.w3.org/WAI/GL/low-vision-a11y-tf/wiki/Informational_Graphic_Contrast_(Minimum)

Cheers,

-Alastair
Received on Wednesday, 16 November 2016 22:34:24 UTC

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