When you are choosing colors for your document, make sure to provide high color contrast between the background and foreground. When choosing foreground and background colors, make sure the ratio between the colors is at least 3:1. See WebAIM Contrast Checker which will allow you to select the colors you are using to see if they meet the guidelines.

Color contrast ensures that users with low vision are able to see your document. A rule of thumb is that if the contrast appears poor, then it probably does not meet the requirement.

The following examples have poor color contrast, and as a result, are difficult to read.

This is an example of poor color contrast

This is an example of poor color contrast

The following examples, however, are easy to read due to the high color contrast between the background and foreground

This is an example of good color contrast

This is an example of good color contrast

Additionally, make sure that color is not the only way that information is emphasized. Users with some visual impairments will not be able to perceive color differences, and therefore will not be able to pick up on any color based emphasis. Consider how patterns, arrows, or text in addition to color can be used to provide emphasis using more than color alone.