the main web-safe color
reference in the Card and the Chart.
In most forms of color blindness, these
colors appear similar to those above. When designing a web site, you
might try to avoid depending on
distinctions that color-blind people
cannot make. About 8% of men and
% of women have some form of
Background Christine Rigden formerly of has a very informative public service site, Safe Web Colours for Colour Deficient Vision . The chart on the right shows a color scheme with a simulation of how it would look in two different types of color blindness. The colors were chosen to be certain anyone could tell them apart. Thomas Wolfmaier runs the Human-Computer Interaction Resources Network , a repository of wisdom in the quest for humans and computers to get along much better than they do. Some content is under subscription but there's a big searchable collection of books, periodicals and other resources. Vischeck has a terrifically practical service . Forget all the theory, just see what your site looks like to color blind users. It will simulate the appearance of an entire web page in various forms of color blindness. (Select the Deuteranope option for the most common.) It can't convert the colors of certain objects, but it does a great job on most features. Highly recommended.
Tests For Color Blindness The following sites may be helpful if you suspect you have color vision deficiency. They are not meant to be diagnostic. See your vision care professional.
Vischeck's color vision model allows you to simulate how the world looks to people with various sorts of color deficiency. As you can see from these examples, 'color blindness' is really a misnomer- most 'color blind' people do in fact see colors! The colors seen may be different than those seen by someone with normal color vision. Also, people with color deficiencies may see certain colors (like red and green) as very similar, while someone with normal color vision sees them as quite dissimilar. (Complete color blindness does occur, but is quite rare.)