What is Colour contrast?
Also called: Color contrast, Contrast ratio
The short answer
Colour contrast is the difference in brightness between text and its background; WCAG AA asks for at least 4.5 to 1 for normal text and 3 to 1 for large text.
What people say: “the text is hard to read”.
Colour contrast, explained
Light grey on white and text over busy images are the usual failures. Contrast checkers give the ratio instantly.
Questions people ask about Colour contrast
What is Colour contrast?
Colour contrast is the difference in brightness between text and its background; WCAG AA asks for at least 4.5 to 1 for normal text and 3 to 1 for large text.
Related terms
WCAG is the international standard for web accessibility from the W3C, organised around four principles (perceivable, operable, understandable, robust) with levels A, AA and AAA.
Colour paletteA colour palette is the fixed set of colours a site uses, typically a background, text colours, one accent for actions and a few states such as success and error.
Dark modeDark mode is a colour theme with light text on a dark background, offered as an alternative to a light theme or matched to the visitor's system setting.
Web accessibilityWeb accessibility means building sites everyone can use, including people who are blind, deaf, have limited movement or cognitive differences, whatever device or assistive technology they use.
Part of the Web Encyclopedia by Apex Flow Digital. Definitions are general knowledge, kept current, with no invented statistics.