Concepts

Accessibility

Understanding color contrast with WCAG and APCA

Web accessibility means designing interfaces that can be read and used by as many people as possible.

When working with color, one of the most important factors is contrast between text and background.

If contrast is too low, many users may have difficulty reading the content.


WCAG contrast guidelines

WCAG (Web Content Accessibility Guidelines) defines minimum contrast standards for readability.

For normal text, common targets are:

  • AA: 4.5:1
  • AAA: 7:1

These values are based on the luminance difference between text and background.


APCA

APCA (Advanced Perceptual Contrast Algorithm) is a newer contrast model designed to improve on traditional WCAG contrast calculations.

It is intended to reflect human visual perception more accurately.

APCA takes factors like these into account more effectively:

  • Perceived brightness
  • Text size
  • Visual differences in color contrast

Accessibility in ColorBread

While generating color scales, ColorBread displays WCAG and APCA contrast information in real time.

This helps you:

  • Check text readability more easily
  • Build more stable UI color structures
  • Create design systems with accessibility in mind

Accessible color structures help more people use your product comfortably.