After the flurry of comments on my last post about accessibility on the web, I wanted to add another tidbit of interesting and related news. An aspect of accessibility that is often not thought of during software and web site design is the troubles that occur for users who are colour blind. Basic usability tenets hold that encoding meaning into colour needs to be done carefully for various reasons such as colour blind users and the large variance in cultural significance for a single colour.
But I’ve always wondered what colour blind users actually experience of my designs. It is a simple thing to activate a screen reader and check to make sure that it is able to convey the meaning of the screen verbally. But how do I check to see what a colour blind person sees?
I came across this neat blog entry by a programmer about a new tool that allows you to preview software in the 3 distinct “flavours” of colour blindness. Note that I did not say you can easily do the preview – it doesn’t look easy at all and seems to be limited to a specific means of building software. However I think tools such as this are a great idea and if we could make this kind of analysis easier and more commonplace I’d be a much happier guy.
I think this sounds even more complicated than designing a web site for the blind. I don’t know much about colour blindness, but have had it described for me by people who are colour blind in one way or another. One friend sees both red and green as the same colour, the only way he can tell at traffic lights is by the order of the lights, another friend sees in shades of grey and one of the profs at my school cannot see the colour blue. Just for fun another teacher would send him emails with the font in blue, and to him it basically looks like a blank page.
It would be a challenge to design the web pages to take into account all the range of colour blindness and I think a better solution is more accesibility functions within the browser. Web browsers interpret and display the data, so for the case of not seeing blue your browser reads blue it could display another colour. And another plus to this solution is that there is only about two or three “commonly” used browsers, but a never ending supply of web pages out there.