RE: /colour/colourblindness.html

I use Vischeck: http://www.vischeck.com/index.php
You can run it on a web page: http://vischeck.com/vischeckURL.php3 (has
problems with CSS, frames, java etc though) or download a filter to use
with Photoshop 

although this looks useful too:
http://www.colorfield.com/insight.html

Gian
-----Original Message-----
From: leeroberts [mailto:leeroberts@roserockdesign.com]
Sent: Wednesday, 6 February 2002 2:53 AM
To: w3c-wai-gl
Subject: RE: /colour/colourblindness.html


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