Color and Graphics
For testing text color on background, we recommend using contrast ratio tools (you are aiming to pass "WCAG AA"):
- WebAIM's color contrast checker (web-based)
- Tanguru contrast-finder(web-based)
- Paciello Color Contrast Analyser (downloadable tool)
Testing all the colors contrast ratios in a complicated graphic is a difficult task. In many cases, it is mathematically impossible for all of the colors to be high-contrast in relation to one another.
We recommend the grayscale test instead:
- Print out your graphic in grayscale.
- Ask yourself:
- Can I tell all the parts apart?
- Can I match them to the legend, if there is one?
- Are any words hard to read, even a little?
- Give your grayscale printout to someone who's never seen it.
- Ask them a few data-related questions about the chart.
If any of these fail, back to the drawing board!