Contrast (Minimum)

Overview

The visual presentation of text and images of text has a contrast ratio of at least 4.5:1, except for large text, incidental text, and logotypes.

Understanding

The W3C Web Accessibility Initiative (WAI) provides detailed guidance on understanding and implementing this criterion. The Understanding document covers the intent, benefits, and supporting techniques in depth.

Techniques

W3C provides documented techniques for meeting this criterion. Each technique links to the full specification with code examples and test procedures.

• G18
• G145
• G148

How to Test

1. 1

   Use a color contrast checker to test foreground/background combinations.

2. 2

   Verify normal text (below 18pt / 14pt bold) meets 4.5:1 contrast ratio.

3. 3

   Verify large text (18pt+ / 14pt+ bold) meets 3:1 contrast ratio.

4. 4

   Check placeholder text, disabled form controls, and logo text.

5. 5

   Test with browser high-contrast mode to confirm readability.