Color Contrast

Accessibility Techniques for Color contrast and use of color
Topic	Technique	WCAG AA Requirement
Use of Color	Use of Color: Any information conveyed by color MUST be accompanied by a programmatically discernible text alternative. Testing methodology 1.4.1.a	Required WCAG 1.4.1
Use of Color	Visible Alternative: Any information conveyed by color MUST be accompanied by a visible alternative (text, image, etc.) that does not depend on color for meaning. Testing methodology 1.4.1.a	Required WCAG 1.4.1
Color Contrast	Small Text Contrast: Small text (under 18 point regular font or 14 point bold font) MUST have a contrast ratio of at least 4.5 to 1 with the background. Note: The contrast rule also applies to images of text, even though images of text are discouraged. Testing methodology 1.4.3.a	Required WCAG 1.4.3
	Large Text Contrast: Large text (at or over 18 point or 14 point bold) MUST have a contrast ratio of at least 3 to 1 with the background. Note: The contrast rule also applies to images of text, even though images of text are discouraged. Testing methodology 1.4.3.b	Required WCAG 1.4.3
	UI Component Contrast: The contrast of UI control boundaries compared to adjacent areas MUST be at least 3 to 1 to distinguish the UI control from the adjacent areas. Testing methodology 1.4.11.a Testing methodology 1.4.11.c	Required WCAG 1.4.11 (WCAG 2.1)
	Visual Focus Indicator Contrast: The contrast of all visual focus indicators against the background MUST be at least 3 to 1. Testing methodology 1.4.11.b	Required WCAG 1.4.11 (WCAG 2.1)
High Contrast Mode	Retain Visible Information: Web content SHOULD retain all essential visual information in Windows High Contrast Mode.	Best Practice
High Contrast Mode	Don't Override: The design SHOULD NOT override Windows High Contrast Mode.	Best Practice