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Web Accessibility

Quick tips that everyone can use to make their websites and pages more accessible.

Color blindness

When selecting colors for a presentation, handout, or other type of visual media, always check that your color choices are distinguishable to users with color blindness. This is especially important if you are combining colored text on a colored background, or are using color to draw attention to an important detail.


Below is an Ishihara color plate as seen by an individual with no color blindness, followed by the same image as seen with protanopia (unable to perceive red light) and deuteranopia (unable to perceive green light). Viewers with no color blindness will see a red background with a green number 74, while viewers with red-green color blindness may see the number 21. Viewers with monochromacy may see nothing but the dots.

Circle made up of red and green dots with the number 74 visible in green. The same circle as seen by someone with the protanopia type of colorblindness.  The same circle as seen by someone with the deuteranopia type of colorblindness

Source: "Ishihara test", Wikipedia, Accessed September 30, 2022.

Color Blindess Simulators