Color Contrast Best Practices
Color contrast is the difference between two colors. Online, color contrast refers to the difference between text color and the background color. Contrast and color might not seem critical at first glance, but for individuals who are colorblind or have other visual impairments, poor contrast can make important content nearly invisible. For example, what appears as highlighted text to some may look like plain gray text to others. When color alone is used to convey meaning, it can exclude users who perceive color differently. To ensure accessibility for all, it's important to use color thoughtfully and verify contrast using tools like contrast checkers or accessible color palettes.
Looking at the example photo below, notice what colors look vastly different to those with varying degrees of color blindness. Utilizing bright reds, yellows, or greens for text or photos with text may be troublesome and cause users to miss crucial information. If emphasis is necessary, consider using dark blue or purple, which is visible to most.
Simulation of Different Color Deficiencies by Johannes Ahlmann is licensed by CC BY.
Examples of Good and Bad Color Contrast
Make sure your text is easy to read against its background. A common approach is to use dark text on a light background or light text on a dark background. However, this doesn’t always guarantee sufficient contrast. To meet WCAG standards, normal-sized text must have a contrast ratio of at least 4.5:1, and large text must meet a minimum of 3:1. See the examples below for both accessible and poor contrast pairings.
Color Contrast Analyzers
Using a color contrast analyzer is a helpful tool to see if visual elements are readable by everyone, including users with low vision or color blindness. Proper contrast helps users distinguish content without strain, making your content more inclusive and compliant with accessibility standards. Free tools like the TPGi Color Contrast Analyzer and WebAIM's Contrast Checker make it easy to test your color combinations for optimal accessibility. Both tools are are based on established web accessibility standards, specifically the Web Content Accessibility Guidelines (WCAG).
Additional Resources
