Hey all, I’ve just been made aware that this wonderful hellsite is letting users specify text colors in your posts now. That’s great! Sounds fun! Assuming, of course, that you can still see the letters.
For people with visual disabilities (especially color blindness or low vision), certain color combinations can be incredibly difficult to read. Black on white (or white on black) is the best, while obviously the worst is when the background and the text are literally the same color.
So how can you know whether a color combination is appropriate?
The World Wide Web Consortium (W3C) has a set of guidelines for creating accessible web content, called the Web Content Accessibility Guidelines (WCAG). WCAG includes standards for text contrast. Specifically, normal text must have a minimum contrast ratio of 4.5:1 with the background to meet WCAG’s Level AA standards. Large text (defined as being at least 14pt and bold or at least 18pt) must have a minimum contrast ratio of 3:1 with the background.
To give a few reference points, white (#ffffff) on black (#000000) has a contrast ratio of 21:1, red (#ff0000) on white (#ffffff) has a contrast ratio of 4:1, and hot pink (#ff0080) on orange (#ff8000) has a contrast ratio of 1.5:1.
If you want to check the contrast ratio between two colors, WebAIM’s Color Contrast Checker is a great online tool to use. It’s fast, easy, and free. It’ll even tell you whether the color combination you input meets WCAG Level AA (or Level AAA, which is more stringent).
Now go, and enjoy your new colorful powers. Just please be considerate of users with disabilities along the way. :)