Understanding Use of Color

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Intent of Use of Color

The intent of this Success Criterion is to ensure that all users can access information that is conveyed by color differences, that is, by the use of color where each color has a meaning assigned to it. If the information is conveyed through color differences in an image (or other non-text format), the color may not be seen by users with color deficiencies. In this case, providing the information conveyed with color through another visual means ensures users who cannot see color can still perceive the information.

Color is an important asset in design of Web content, enhancing its aesthetic appeal, its usability, and its accessibility. However, some users have difficulty perceiving color. People with partial sight often experience limited color vision, and many older users do not see color well. In addition, people using text-only, limited-color or monochrome displays and browsers will be unable to access information that is presented only in color.

Examples of information conveyed by color differences: “required fields are red", “error is shown in red", and “Mary's sales are in red, Tom's are in blue". Examples of indications of an action include: using color to indicate that a link will open in a new window or that a database entry has been updated successfully. An example of prompting a response would be: using highlighting on form fields to indicate that a required field had been left blank.

This should not in any way discourage the use of color on a page, or even color coding if it is redundant with other visual indication.

Benefits of Use of Color

Examples of Use of Color

Resources for Use of Color

Techniques for Use of Color

Sufficient Techniques for Use of Color

Situation A: If the color of particular words, backgrounds, or other content is used to indicate information:

  1. Ensuring that information conveyed by color differences is also available in text
  2. Including a text cue whenever color cues are used
  3. Ensuring that additional visual cues are available when text color differences are used to convey information
  4. Using a contrast ratio of 3:1 with surrounding text and providing additional visual cues on focus for links or controls where color alone is used to identify them

Situation B: If color is used within an image to convey information:

  1. Using color and pattern
  2. Ensuring that information conveyed by color differences is also available in text

Additional Techniques (Advisory) for Use of Color

Common Failures for Use of Color