1. Accessibility & Legislation
  2. Common Issues
  3. Testing & Tools
  4. Analysing Your Site

2.05 Common issues: Colour usage

Taken from the W3C

Ensure that text and graphics are understandable when viewed without colour.

If colour alone is used to convey information, people who cannot differentiate between certain colours and users with devices that have non-colour or non-visual displays will not receive the information. When foreground and background colours are too close to the same hue, they may not provide sufficient contrast when viewed using monochrome displays or by people with different types of colour deficits.


  1. Colour blindness - colour wheel.
  2. Colour blindness - photo example.
  3. Age effects.
  4. Without colour.
  5. Dyslexia.
  6. Flashing, flickering or blinking content.
  7. Summary.

Who does this affect?

The WAI guidelines:

Further information:

Common issues