A11ying with Sanna - Web Content Accessibility Guidelines a guide to the accessibility requirements
1 Perceivable

1.4.6 Contrast (Enhanced)

Conformance level: AAA
Criterion released in WCAG version: 2.0

Official description of the success criterion

The visual presentation of text and images of text has a contrast ratio of at least 7:1, except for the following:

  • Large Text: Large-scale text and images of large-scale text have a contrast ratio of at least 4.5:1;
  • Incidental: Text or images of text that are part of an inactive user interface component, that are pure decoration, that are not visible to anyone, or that are part of a picture that contains significant other visual content, have no contrast requirement.
  • Logotypes: Text that is part of a logo or brand name has no contrast requirement.

What to do?

Provide a higher contrast ratio for text and images of text.

Why is it important?

Supports users with severe visual impairments.

How to test for it?

Check that the contrast between text/images of text and their background is at least 7:1. With large text, the requirements are lower: 4,5:1.

More about this criterion elsewhere