Technique G148:Not specifying background color, not specifying text color, and not using technology features that change those defaults

Description

The objective of this technique is to make sure that users can read text that is presented over a background. With this technique the author avoids having to do any contrast measures by simply not specifying the text color and not specifying the background. As a result the colors of both are completely determined by the user agent.

Some people who have vision disabilities set their user agent to override certain colors that they have trouble seeing. This technique will help avoid a situation where the user agent and web site conflict with each other over the foreground and/or background colors resulting in the same color for text and background, which would make it invisible for user who set their own colors in their browser or Assistive Technology.

Examples

Related Resources

No endorsement implied.

• TPGi Colour Contrast Analyser (CCA) – Application
• Contrast Ratio Analyser - online service
• Color Contrast Samples
• Atypical colour response
• Colors On the Web Color Contrast Analyzer
• Tool to convert images based on color loss so that contrast is restored as luminance contrast when there was only color contrast (that was lost due to color deficiency)
• List of color contrast tools

Related Techniques

• G18: Ensuring that a contrast ratio of at least 4.5:1 exists between text (and images of text) and background behind the text
• G156: Using a technology that has commonly-available user agents that can change the foreground and background of blocks of text

Tests