Approximately one in twenty have a form of Dyschromatopsia, colorblindness or color vision deficiency with men being more likely than women to be colorblind; 7% of US males and only 0.4% of females having difficulty in distinguishing red from green, or see red and green differently than others.
There are two types of color blindness, total and partial. Partial colorblindness is then made up of two subsets, red-green and blue-yellow followed by two subsets for each, Dichromacy and Anomalous trichromacy with each having set types of colorblindness within each group.
As a result, the web community must create an atmosphere which makes it easier for colorblind individuals to differentiate between text and background along with images.
One way to test your website for usability is by using one of these two tools:
Each tool will show a copy of your website as if it was seen as a select type of colorblindness.
Firefox also has a great add-on which allows webmasters to see color contrast:
Written: Sep 15, 2007
Tags: colorblind, visitors
Content Readability
September 16, 2007 @ 4:42 pm | Reply
[...] Background/text contrast is a bit of a no-brainer; however, many first-timers don’t understand the concept to its fullest. Although black (I prefer #333 or #474747) on white is generally the best, there are times when colors need to be used (like headers, banners, footers). One thing to remember here is just because you can see it, others might not be able to. [...]