When using colour, you must make sure that any information conveyed with colour is also conveyed in black and white. For example, if you’re using colour to identify key words in a document, make sure that you also make them stand out in another way (for example, by putting them in bold; italics are not recommended).
Colour Contrast
You must provide high colour contrast to the text in your document. A good example of high colour contrast is black and white; while an example of poor colour contrast is light yellow and white. Colour contrast accessibility ratios define the minimum difference in luminance between text and its background to ensure readability for users with visual impairments. In order to meet WCAG Level AA, standard text must have a contrast ratio of at least 4.5:1 while large text (headings, etc.) needs a 3:1 ratio.
Colour Contrast Checker
TPGi’s free color contrast checker tool that allows you to easily determine the contrast ratio of two colors simply using an eyedrop tool.