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Graphics contrast

From: Alastair Campbell <acampbell@nomensa.com>
Date: Thu, 3 Nov 2016 16:56:44 +0000
To: LVTF - low-vision-a11y <public-low-vision-a11y-tf@w3.org>
Message-ID: <3F69CA87-5314-4B58-BA0C-FF30F4D60C00@nomensa.com>
Hi Everyone,

Immediately after the call I started putting Glenda’s update to the SC text in, and whilst doing that the similarity with the current 1.4.3 sprang to mind.

How about aligning more closely with 1.4.3?

The visual presentation of important information in graphical elements has a contrast ratio of at least 4.5:1 against the immediate surrounding background, except for the following:

  *   Thicker lines: where the minimum width of the line is at least 3px the graphic has a contrast ratio of at least 3:1;
  *   Incidental: Graphical elements that are not required for the understanding of the graphic, that are pure decoration, that have the information duplicated elsewhere on the same page have no contrast requirement;
  *   Logotypes: Graphics that are part of a logo or brand name have no minimum contrast requirement.

I went with “graphical elements” to open up the further description to sub-graphics, e.g. a line in an info-graphic is a graphical element, and if it is important then it should have contrast against its surroundings.

As I said, if anyone has particularly good/bad examples of graphics please send them to me and I’ll try testing this against them.



Alastair Campbell

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Received on Thursday, 3 November 2016 16:57:20 UTC

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