Color and Graphics

Color Contrast Tools

For testing text color on background, we recommend using contrast ratio tools (you are aiming to pass "WCAG AA"):


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:

  1. Print out your graphic in grayscale.
  2. 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?
  3. Give your grayscale printout to someone who's never seen it.
  4. Ask them a few data-related questions about the chart.

If any of these fail, back to the drawing board!