Colour contrast

If colour is used to convey information, then another way of conveying that information that is accessible to people who cannot perceive colour must be presented.

All text must have enough contrast against its background to meet WCAG 2.2 AA. This applies to all text, not just text overlaid on images. The minimum contrast ratios are:

• 4.5:1 for body text
• 3:1 for large text (18pt, or 14pt bold)
• 3:1 for icons, buttons and form field borders

Tools such as WebAIM Color Contrast should be used to test colour contrasts. For Mac, there is also Contraste.