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LibGuides Accessibility

Internal UC Irvine Libraries resource guide to promote best practices in guide accessibility.

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Overview

Color contrast

Colors must have sufficient contrast between text color and its background (technically called luminosity contrast ratio). This includes text on images, icons, and buttons. Also, colors used to convey information on diagrams, maps, and other types of images must be distinguishable.

This is especially helpful for individuals with color blindness. Color-blindness does not literally mean that a person can't see any color at all (except in very rare cases). Color-blindness refers to the inability to distinguish between certain kinds of colors, especially colors that are of equal brightness or luminosity, even if the colors themselves appear quite different to people without color-blindness.

Text and images of text must have a contrast ratio of at least 4.5:1. Large-scale text and images of large-scale text (with at least 18 point or 14 point bold or font size that would yield equivalent size for Chinese, Japanese and Korean fonts) must have a contrast ratio of at least 3:1.

Color should never be the sole means of conveying information

Color, alone, is insufficient to distinguish certain information. Instead, use color plus another element to emphasize a point or visually distinguish information differences, such as: bold, size, patterns, or shapes.

Additional resources