C. Colorblindness/Color Deficiency
Although considered only a minor disability, slightly fewer than 10% of all men suffer some form of colorblindness (also called color deficiency), so this audience is very widespread. Colorblind users are unable to distinguish certain color cues, often red versus green.
Read the Color and Colorblindness page for more detailed explanation of these deficiencies and how to accommodate them.
The two images below show a color-coded menu; first as it appears to a user with normal vision, and then as it appears to a user with a visual color deficiency.
Viewed by Color Deficient User
For users with colorblindess or color deficiency, it is important that color-coded information be available with another visual cue such as changes in shape, line texture or a text-based code. For example, in the color-coded menu above, even though the red and orange colors are muted, the user can still read the text and know to which sections they refer.
- Users with severe visual impairment, since screen readers cannot spell out color differences.
- People using a black and white printer.
- Cal Henderson: Color Vision—Lets users test color schemes while simulating almost all forms of colorblindness.
- Visicheck Colorblindness Tester—Allows users to view images and live Web pages while simulating red-green and blue-yellow color deficiencies.