Color is often used for emphasis, to attract attention, or to enhance the visual representation of shapes, such as states and countries on a map. However, learners with color blindness or low vision may not be able to recognize or sufficiently distinguish colors from each other.

Color Contrast and Low Vision

Learners with low vision may have trouble distinguishing text from background colors without sufficient color contrast between the text and the background.

Stick to higher color contrast combinations such as black on white or dark blue on yellow to promote better readability. A ratio of 4.5 to 1 is the minimum contrast ratio for small text sizes such as 10- or 12-points. Use the accessibility checkers built into Microsoft Word and PowerPoint as well as Desire2Learn’s Web editor to help you determine if your colors meet accessibility guidelines for color contrast.

Color Blindness

Color blindness is the inability to perceive certain colors [Figure 1]. Deurteranopia (green blindness) and Protanopia (red blindness) are the two most common types of color blindness affecting up to 8% of males; females are much less susceptible to color blindness.

Designing for Color Blindness

Avoid using only color for emphasis or to convey information. For charts and graphs that rely on color, provide labels or use a second graphic device to explain the data visually. For the graph in Figure 2, learners with either red or green blindness may refer to the dashed or solid lines to help them understand the data.