Color Accessibility
Table of Contents
Overview
Accessible color design ensures all users, including those with color vision deficiency, can access and understand information.
When to Use
- Creating color palettes
- Designing data visualizations
- Testing interface designs
- Status indicators and alerts
- Form validation states
- Charts and graphs
Quick Start
Minimal working example:
WCAG Contrast Ratios:
WCAG AA (Minimum):
- Normal text: 4.5:1
- Large text (18pt+): 3:1
- UI components & graphical elements: 3:1
- Focus indicators: 3:1
WCAG AAA (Enhanced):
- Normal text: 7:1
- Large text: 4.5:1
- Better for accessibility
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Testing Contrast:
Tools:
- WebAIM Contrast Checker
- Color Contrast Analyzer
- Figma plugins
- Browser DevTools
Formula (WCAG): Contrast = (L1 + 0.05) / (L2 + 0.05)
Where L = relative luminance
// ... (see reference guides for full implementation)Reference Guides
Detailed implementations in the references/ directory:
| Guide | Contents |
|---|---|
| Color Contrast Standards | Color Contrast Standards |
| Color Vision Deficiency Simulation | Color Vision Deficiency Simulation |
| Accessible Color Usage | Accessible Color Usage |
| Testing & Validation | Testing & Validation |
Best Practices
✅ DO
- Ensure 4.5:1 contrast minimum (WCAG AA)
- Test with color blindness simulator
- Use patterns or icons with color
- Label states with text, not color alone
- Test with real users with color blindness
- Document color usage in design system
- Choose accessible color palettes
- Use sequential colors for ordered data
- Validate all color combinations
- Include focus indicators
❌ DON'T
- Use color alone to convey information
- Create low-contrast text
- Assume users see colors correctly
- Use red-green combinations
- Forget about focus states
- Mix too many colors (>5-8)
- Use pure red and pure green together
- Skip contrast testing
- Assume AA is sufficient (AAA better)
- Ignore color blindness in testing