ColorBlindness and Access

4% of Web users have some form of colorblindness.

• Never rely upon color alone to convey information.

• Provide enough contrast between your font colors and the background.

Unacceptable:

The following students listed in green have passed with honors. The students listed in red must repeat the class.

Joe Blow
Doug Smith
Marianne Summers

Better:

The following students listed in green and marked with asterisks (*) have passed with honors. The students listed in red and marked with # must repeat the class.

Joe Blow
Doug Smith #
Marianne Summers *

In the second example above, even someone with colorblindness who cannot distinguish red from green will be able to understand the content.

Helpful Links:

• test graphics for colorblindness with vischeck.com -- free
• Visolve transforms colors for people with colorblindness -- free
• Evaluate your site