Technique G111:Using color and pattern

Applicability

All technologies that support images.

This technique relates to 1.4.1: Use of Color (Sufficient).

Description

The objective of this technique is to ensure that when color differences are used to convey information within non-text content, patterns are included to convey the same information in a manner that does not depend on color.

Examples

Example 1

A real estate site provides a bar chart of average housing prices in several regions of the United States. The bar for each region is displayed with a different solid color and a different pattern. The legend uses the same colors and patterns to identify each bar.

Example 2

An on-line map of a transportation system displays each route in a different color. The stops on each route are marked with a distinctive icon such as a diamond, square, or circle to help differentiate each route.

Example 3

A flow chart describes a set of iterative steps to complete a process. It uses dashed, arrowed lines with a green background to point to the next step in the process when the specified condition passes. It uses dotted arrowed lines with a red background to point to the next step in the process when the specified condition fails.

Example 4

The content includes an interactive game. The game pieces for the 4 players are distinguished from one another using both color and pattern.

Tests

Procedure

For each image within the Web page that use color differences to convey information:

  1. Check that all information that is conveyed using color is also conveyed using patterns that do not rely on color.

Expected Results

  • Check #1 is true.