Webstandards, Accessibility and Usability at Penn State

This Page

1. About Color Deficiency
2. Demo
3. Accommodation Needed
4. Hidden Audience
5. Color Blindness Simulators

About Color Deficiency

Although considered only a minor disability, slightly under 10% of all men suffer some form of color blindness, so this audience is actually very widespread. Color blind users may not be able to distinguish certain color cues, especially red versus green.

Read the Color and Color Blindness section for more detailed explanation of these deficiencies and how to accomodate them.

Demo

Accommodation Needed

For this audience, it is important that color coded information be available with another visual cue such as changes in shape, line texture or just 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 to know which sections they refer to.

Hidden Audience for Color Blindness

1. Screen readers also cannot spell out color differences, so alternatives to color changes must also be included for users with severe visual impairment.
2. People using a black and white printer.

Top of Page

Color Blindness Simulators

1. Color Vision (Cal Henderson) - Test color schemes with almost all forms of color blindness

2. Visicheck Color Blindness Tester - Allows you to test images and live Web pages for red-green and blue-yellow. color deficiencies.

About Color Blindness

• Lighthouse Org Color Contrast - General tips on how to combine colors.
• University of Minnesota Duluth Color Links - Includes a variety of color blindness resources.
• Joe Clark - A very accessible description of the different types of color blindness.
• Colors for the Color Blind - An informative yet wry look at color blindness from an actual "user". Includes links to utilities for the color blind.
• Firelily
• WebAIM Color Blindness
• Visibone - Scroll down for color blindness information

Top of Page