All technologies that support images.
This technique relates to:
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.
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.
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.
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.
The content includes an interactive game. The game pieces for the 4 players are distinguished from one another using both color and pattern.
No resources available for this technique.
For each image within the Web page that use color differences to convey information:
Check that all information that is conveyed using color is also conveyed using patterns that do not rely on color.
Check #1 is true.
If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.
Techniques are informative—that means they are not required. The basis for determining conformance to WCAG 2.0 is the success criteria from the WCAG 2.0 standard—not the techniques. For important information about techniques, please see the Understanding Techniques for WCAG Success Criteria section of Understanding WCAG 2.0.