Access by Various artists

I found this little gem

Colour Contrast Analyser

You can show the contrast ratio for different types of colour blindness.

It is from WAT-C "Web Acccessibility Tools Consortium".

Of all things I use it to educate shooting range designers for picking the colours for target numbers!

Thanks for giving emphasis to the importance of communicating with and getting feedback from groups of people with disabilities when designing applications and websites. In addition, I believe that it is a good idea to start the conversation with these groups during the development stage of an app or site, rather than finishing the product and getting in touch with them afterwards.

That is an excellent point - the earlier in the process you talk with real people the better.

The later you leave accessibility considerations in a project, the more expensive retro-fitting will be required. A bit like adding wheelchair access to a building. Very cheap to design in from scratch, very expensive, and often a compromise, if added later.

Some projects use 'personas' - a written representation of an end-user - and these are useful as a reference points, but no substitute for real people and conversations.

might be of interest....

http://alistapart.com/article/accessibility-the-missing-ingredient