- From: Joe Clark <joeclark@joeclark.org>
- Date: Fri, 19 Sep 2003 11:27:39 -0400 (EDT)
- To: WAI-IG <w3c-wai-ig@w3.org>
> The W3C's draft techniques document for Accessibility Evaluation and > Repair Tools at [15]http://www.w3.org/TR/AERT#color-contrast provides an > algorithm for testing to see if text and background colours provide > sufficient contrast. That issue cannot be programmatically determined, full stop. Every visually-impaired person is different. It's *not* like colour deficiency, which has well-understood patterns and easy-to-follow accommodations. Cf.: <http://joeclark.org/f2f/deficiencies.html#colour-structure-impl> <http://joeclark.org/f2f/recommendations.html#colour> > The document indicates, however, that the algorithm is a "suggested" one > that is "still open to change". Can anyone shed any light on whether > this should be considered as a reliable indicator of colour contrast, or > whether some more authoritative/reliable algorithm exists? No and no. > Reason for my question: sponsors/clients of a project I am currently > working on believe that the requirements are too stringent. This view > was expressed after I used the algorithm to generate a report on a range > of colour options that were being considered--very few of them passed > muster, as I expected. The correct accommodation method is for an author to provide a means of altering colours, as with a stylesheet-switcher. The visitor can also adjust browser controls or employ a user stylesheet including !important declarations. -- Joe Clark | joeclark@joeclark.org Author, _Building Accessible Websites_ <http://joeclark.org/access/> | <http://joeclark.org/book/>
Received on Friday, 19 September 2003 11:26:20 UTC