Portland Community College | Portland, Oregon

Color

Approximately 8% of men worldwide have some sort of color-blindness. The number increases to about 10-11% in areas with predominately Caucasian populations.  The most prevalent type of colorblindness affects the red-green spectrum. In the image below, you can get a visual indication as to what is it is like for someone with red or green colorblindness to view color. Those with colorblindness may see these colors in a grayed out version of varying hues that might be very difficult to distinguish.

Because of this, it is important to not use color alone to convey information. For example, if you need to create a bar chart using different colors, have the bar also be textured too. This way if someone can’t distinguish the color, they can distinguish it by texture. If a line chart, have dashed and dotted lines to accompany the color. If you use colored text for emphasis, bold or italicize it too. Color is okay as long as it is used in the right way.

Color contrast between background colors and text colors (or even an image or clipart) needs to be sufficient as well. In the image below, it could be difficult for someone who can’t see green very well or who has low vision to make out the clip art image clearly.

DIY Accessibility Checking