Spider Trax

Designing For Dyslexics: Part 2

In the second article of the series on accessites.org, I’ve returned to the issue of color contrast. As you might have gathered, it’s a hot topic of mine. Primarily because it’s an area that I believe WCAG has completely overlooked but also because I think it’s an issue that can be remedied relatively easily.

However, I’m aware that, whenever you reduce a barrier for one group, there’s always the possibility that you have inadvertently created one for another group with opposing needs.

So, in this case, we need to ask the following:

1. Would lowering the recommended color threshold to 400 create significant problems for the visually impaired?
2. If ‘yes’, how should this problem be addressed without impacting on dyslexic users?
3. If ‘no’, should a lowered color threshold be promoted as Best Practice?

I’m also interested in gathering evidence about the impact of higher color contrasts. At present, I’m suggesting a threshold of 600 or above should be accompanied by a warning but I’m only using this figure as a starting point. What we really need to know is:

1. At what point does the color threshold become so high that it poses a major problem for dyslexics?
2. At what point does the color threshold become so high that it poses a problem for users of Zoom Text?

I’ve created a test page of six high contrast blocks - from black on white at a color difference threshold of 765 reducing in roughly 50 unit increments down to a color difference of 525. I’d be interested in hearing what issues these create for the above users.

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