Links must be distinguished from surrounding text in a way that does not rely on color

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Rule Description

Ensures users who cannot distinguish between colors can tell when text is a link. Sufficient color contrast ratio of 3:1 is necessary to distinguish link text color from surrounding text color.

The Algorithm, in Simple Terms

Checks all links that appear in blocks of text for a color contrast difference of at least 3:1 with the surrounding text to ensure that users who cannot distinguish between the colors can still find the link.

Why this is Important

Some people with low vision experience low contrast, meaning that there aren't very many bright or dark areas. Everything tends to appear about the same brightness, which makes it hard to distinguish links. Text that is too close in luminance (brightness) to the background (or adjacent text) can be hard to read.

How to Fix the Problem

Ensure all links that appear in blocks of text have a color contrast difference of at least 3:1 with the surrounding text to ensure that users who cannot distinguish between the colors can still find the link.

Compliance Data & User Impact

User Impact: Critical
Disabilities Affected:
  • Low Vision
  • Color-blindness
Issue Type:
  • WCAG 2.0 (A): SHOULD
  • Deque Experimental
WCAG Success Criteria:
  • 1.4.1 Use of Color
Section 508 Guidelines:
  • Not applicable

Related Deque University Course Pages

Other Related Resources

Additional Information

Relevant Technologies:
  • HTML 4
  • HTML 5
Test Reliability: Automated testing is possible, with high accuracy
Rule ID: link-in-text-block