They have on-line color-blind image filtering.
It's better for sites with lots of images.
TIP Take a screenshot of your page, save it, and then go to Vischeck.
The data used for some color data filtering comes from Hans Brettel's site at
It accompanies the article "Digital Video Colourmaps for Checking the Legibility of Displays by Dichromats"
by Françoise Viénot, Hans Brettel, and John D. Mollon, published in the August 1999 issue of Color Research and Application 24, 243-252.