Color Blindness Accessibility

Color-vision differences affect how people distinguish certain hues. A website fails users when a red outline is the only signal of a missing form field, when a chart legend depends only on green versus orange, or when a link is recognizable only through a subtle color shift. Accessible design provides another cue such as text, shape, pattern, an icon with an adequate label, or a visible underline.

WCAG 2.2 Success Criterion 1.4.1 states that color must not be the only visual means of conveying information or indicating an action. Contrast is a related but separate concern: the normal-text minimum in Success Criterion 1.4.3 is generally 4.5:1, with defined exceptions and a lower threshold for large text. Passing contrast alone does not ensure that two differently colored chart series are distinguishable. Check forms, status chips, maps, calls to action, and focus indicators in more than one viewing condition.

A brand does not have to abandon color to be accessible. Preserve the palette while adding redundant information cues and testing actual tasks. This term complements, but is not identical to, the broader Use of Color (Accessibility) criterion, because it translates color-vision needs into practical interface patterns.