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RE: Colour blindness and accessibility

From: Nick Kew <nick@webthing.com>
Date: Wed, 30 Apr 2003 07:13:20 +0100 (BST)
To: "Matthew R. Moore" <mrmoore@truman.edu>
cc: Lois Wakeman <lois@lois.co.uk>, w3c-wai-ig@w3.org, immelie@hotmail.com
Message-ID: <Pine.LNX.4.21.0304300654290.1099-100000@jarl.webthing.com>

On Tue, 29 Apr 2003, Matthew R. Moore wrote:

> When we had a seminar on accessibility, one of my friends here at
> the University (who is color deficient) mentioned that until a week or
> two before the meeting, he didn't realize that MS Word underlined
> mis-spelled
> words in red and grammatical errors in green (when those options are turned
> on).

Hmmm.  I don't know how he could deal with that.

> Another example along the same vein that we discussed is when form
> validators change
> the color of the text on the form to a certain color (i.e. red) and say that
> "fields in
> red must be completed" - if someone can't distinguish red for some reason,
> how can
> they know that the form field is required?

Now that on the other hand is easy, and serves to demonstrate the
inherent accessibility of HTML/CSS (when not abused).  The author
specifies in CSS
.mandatory	{ color: red ; }

and the colour-blind user has an instant override, specifying a user
stylesheet that distinguishes mandatory fields in a manner that is
accessible to him.

> I can't speak for how accurate it is, but at
> http://www.vischeck.com/vischeck/
> there is a mechanism to test how your site would look to individuals with
> certain
> color vision deficiences.

Looks interesting, though I'm no more qualified than you to pronounce
on its accuracy.  Seems to embed the CSS, rewriting colour attributes
on-the-fly.  Sort-of like a CSS-selector choice of document views
in reverse.

Nick Kew

In need of paying work - http://www.webthing.com/~nick/cv.html
Received on Wednesday, 30 April 2003 02:13:26 UTC

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