A computer is like an Old Testament god - lots of rules and no mercy.
Does W3C Get Its Contrasts Wrong?
If you follow W3C recommendations regarding colour contrast, you could be actively creating problems for as many as 10% of your site visitors.
It is estimated that as many as 1 in 10 people are dyslexic.
The current population of the UK is around 60.2 million.
National Statistics Online
This implies that the number of dyslexics in the UK is likely to be in the region of 6 million.
The number of visually impaired people in the UK in April 2005 was estimated at 1.7 million. This figure includes all those who have a visual disability that cannot be corrected by spectacles. It includes people who are entitled to register as blind or partially sighted, or who have difficulty reading an ordinary-print newspaper and whose sight restricts their mobility.
Chartered Institute of Library and Information Professionals
So, in the UK, the number of dyslexics outnumber the visually impaired users by at least 3:1.
I assume that these proportions would be roughly similar in other areas of the world.
So, why does WCAG 1.0 focus exclusively on ensuring that pages contain ‘sufficient contrast’?
2.2 Ensure that foreground and background color combinations provide sufficient contrast when viewed by someone having color deficits or when viewed on a black and white screen.
Nothing about the significantly larger group who will be actively disabled by high contrasts. Not one word about the issues that can actually be created when applying their suggested algorithm.
I’m not suggesting that developers ignore colour contrast issues or consign W3C’s suggested algorithm to a category marked ‘Useless’. To do so would be to actively disable a significant number of visually impaired users.
What I am suggesting is that, if a colour theme is chosen that does conform to the W3C algorithm, an alternative, low contrast stylesheet should be provided as standard. If that’s not an option, consider lowering the contrast slightly. Yes – I mean drop the color difference below that recommended by W3C to 400 instead of 500. This would be in accordance with the range used by Hewlett Packard which recommends a colour difference limit of 400.
I’ve put together a simple test page to demonstrate this in action with examples of colour combinations that do not comply with W3C’s and similar ones that do. I, personally, find the ‘non-compliant headings’ far easier on the eye, yet the W3C recommendations do not make any allowance for bold text – a factor that should be relevant when considering colour contrasts.
I think less emphasis on higher contrasts, greater allowances for bold text and a slight reduction in the threshold for color difference will result in pages that will be slightly easier for the larger group of dyslexic users to read whilst not severely impacting on the smaller group of visually disabled users. A positive ‘side effect’ may well be that users without any special needs will find the slightly lower contrast pages less tiring on the eyes – thus enhancing overall readability.