Colour Contrast
The old Accessibility Evaluation and Repair Tools (AERT) suggested algorithm for determining colour contrast now directs here. The AERT algorithm was never a recommendation, and WCAG 2.0's luminosity contrast algorithm is recommended instead.
Success Criterion 1.4.3 of WCAG 2.0 requires the visual presentation of text and images of text has a contrast ratio of at least 4.5:1, except for the following:
- Large Text: Large-scale text and images of large-scale text have a contrast ratio of at least 3:1;
- Incidental: Text or images of text that are part of an inactive user interface component, that are pure decoration, that are not visible to anyone, or that are part of a picture that contains significant other visual content, have no contrast requirement.
- Logotypes: Text that is part of a logo or brand name has no minimum contrast requirement.
Analyse Luminosity Contrast Ratio
Large Text Sample
Large text sample.
Regular Text Sample
Regular text sample.
Results for Luminosity Contrast Ratio
The contrast ratio is: 2.05:1
Fail: The luminosity contrast ratio is insufficient for the chosen colours (#fff and #99b3ff).