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Re: Inaccessible by color blind? http://www.tryspot.com/tharapita/

From: David Woolley <david@djwhome.demon.co.uk>
Date: Fri, 13 Apr 2001 01:08:23 +0100 (BST)
Message-Id: <200104130008.f3D08Om19192@djwhome.demon.co.uk>
To: w3c-wai-ig@w3.org
> http://www.tryspot.com/tharapita/ is hard to view by color-blind people. This
> really has made me concerned because I really want my sites to be accessible by
> color-blind people as well.

Assuming it is still there,
<http://www.labs.bt.com/people/rigdence/colours/index.html>
is a good resource.  It includes palettes for simulating the effects
of different types of colour blindness.

This should not be confused with their corporate site which has had
me resorting to disabling colours in the past, even though I'm not colour
blind.

I think the basic rules are:

- contrast light colours with dark colours;
- contrast bluey colours with yellow/brown colours.

Your home page seems to fail the first point, but not the second.  However,
it is possible that colour blindness reduces the contrasts even further
than they are already reduced.  From my point of view, the black on blue
is the problem, rather more than the blue on grey.

If you convert the image to greyscale - always a good test - the black
on blue is essentially unreadable, but the blue on grey is still OK.

The other problem it has, is that the background has alternate scan lines
light and dark.  That causes interlaced displays to flicker badly.  I'm 
not sure what frequencies tend to trigger epilepsy, but it is something
you should consider.  It is certainly annoying.
Received on Thursday, 12 April 2001 20:08:28 GMT

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