Contrast Ratio
A number saying how easy text is to read against its background.
Definition
A numeric measure of the luminance difference between two colours, from 1:1 to 21:1.
Craft convention. True because the industry converged on it. Breaking it costs familiarity, not correctness.
On this plate
In plain language
A number saying how easy text is to read against its background.
Example
Body text needs 4.5:1 against its background to meet WCAG AA.
Local chart
TERM·057 · Region X · Grid C6
This entry and the entries it is stated to connect with. Each line is labelled with what the connection means.
Continue from here
Each link says what the connection is, so you can tell a principle from an alternative from a thing people mix this up with.
Deeper reading
The full entry behind this definition.
- Color AccessibilityFND·028 · UI foundation
- ContrastFND·002 · UI foundation
- LightnessFND·022 · UI foundation
Nearby in the Atlas
Adjacent territory, found through shared tags rather than a stated link.