Color
There are two main issues when dealing with colors, web pages, and persons with a disability. First, do not rely on color alone to convey information. This practice can be seen throughout the United States road system as street lights not only have a color but a position (i.e. top, middle, bottom) and street signs are shaped differently as well as having different colors. Certain visual disabilities affect color comprehension as well as general sight. Therefore using different colors alone on a pie chart may leave a portion of your users unable to access information. Instead, use colors and data labels.
The other main issue is color contrast. The default color contrast in most applications is black and white; black text on a white background. This strong color contrast allows for general ease of reading. Once again, some visual disabilities affect color comprehension as well as general sight so be sure to choose foreground and background colors with a strong contrast.
Example
Don't use color alone
In the first example below, the correct answer to the quiz question is green. Without color, there is no way to tell which one is the answer.
Not Accessible
- Abraham Lincoln
- Millard Fillmore
- Andrew Jackson
Accessible
- Abraham Lincoln
- Correct Answer: Millard Fillmore
- Andrew Jackson
Use Strong Color Contrast
Not Enough Contrast
Good Contrast
Not Enough Contrast
Good Contrast
Links
WAI Color
Checkpoint
(http://www.w3.org/WAI/wcag-curric/chk3-0.htm)
Creating Accessible
Images
(http://www.webaim.org/techniques/images/2)
Effective
Color Contrast
(http://www.lighthouse.org/color_contrast.htm)
