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RE: /colour/colourblindness.html

From: Lee Roberts <leeroberts@roserockdesign.com>
Date: Tue, 5 Feb 2002 09:53:17 -0600
To: "WCAG List" <w3c-wai-gl@w3.org>
Message-ID: <NFBBJHFEOLAGEICMIMBPCELMCBAA.leeroberts@roserockdesign.com>
Here is some good color-blind information.

http://www.delamare.unr.edu/cb

Web Page Design for Colour Blind Readers

DO provide ALT="..." text for all your images. If a user cannot understand
your image they can reload with images off. Consider using JavaScript
MouseOver events to provide status-line descriptions of images- especially
maps and navigation bars.

DON'T use [red | green | brown | grey | purple] [next to | on top of |
changing to] [red | green | brown | grey | purple].

DO have a strong, bright contrast between foreground and background colours-
not only for your page text but also in your images. Even totally colour
blind readers can differentiate similar colours which contrast bright with
dark.

DON'T use colours in images to denote special areas, such as bar charts,
maps and navigation bars. Consider using textures or line shading instead
(try the "paper" or "pattern" function in your graph or painting program).
Alternatively, provide additional written labels.

DO use blue, yellow, white and black if you really must use colours to
distinguish items. These combinations are less likely to be confused than
others.

An even better web site for information on color-blindness is
http://www.lighthouse.org/color_contrast.htm

I hope this helps everyone.

Thanks,
Lee Roberts
President/CEO
Rose Rock Design, Inc.
http://www.roserockdesign.com
Received on Tuesday, 5 February 2002 12:52:42 GMT

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