Color is not used as the only visual means of conveying information, indicating an action, prompting a response, or distinguishing a visual element. (Level A)

Rationale

Color cannot be the only visual means of conveying information, because many users have deficiencies in color perception and cannot identify or distinguish colors. This checkpoint requires that you provide another non-color method for making the information available visually, such as with pattern, images, text, or text formatting.

For example, if  text in an input field is colored red to show it is invalid, a user who cannot distinguish the red will not be able to detect the problem. If a warning symbol is added beside the text box then the user can locate it.

This checkpoint is not meant to discourage the effective use of color or color coding, but to require redundant visual indication.

Exception: This checkpoint does not apply when color is used to indicate "visited" links. This checkpoint also does not apply when color is used to indicate the location of a mouseover focus on a navigation bar or within an application.

Refer to Understanding SC 1.4.1 for more information (external link to WCAG).

Development Techniques

Review the General techniques as well as other tabs applicable to your technology.  Prioritize the use of technology-specific techniques, and implement the General techniques as needed. You are always required to find, understand and implement accessible code techniques to meet the checkpoint. The documented techniques and supplements are not exhaustive; they illustrate acceptable ways to achieve the spirit of the checkpoint. If numbered, techniques are in order of preference, with recommended techniques listed first. Where used, IBM information that complements the WCAG techniques is indicated as supplemental.

General techniques

Instructions: Select the situation below that matches your content. Any item in the described situation represents a technique that is deemed sufficient for meeting this checkpoint. Ensure you review WCAG Common Failures to avoid development mistakes.

Situation A: If the color of particular words, backgrounds or other content is used to indicate information

Situation B: If color is used within an image to convey information

Web (HTML, ARIA, CSS) techniques

There are no specific Web techniques for this checkpoint. Refer to the General techniques section.

Mobile Native (iOS) techniques

There are no specific Mobile Native iOS techniques for this checkpoint. Refer to the General techniques section.

Eclipse techniques

There are no specific Eclipse techniques for this checkpoint. Refer to the General techniques section.

Windows-based (MSAA+IA2) techniques

There are no specific Windows-based (MSAA+IA2) techniques for this checkpoint. Refer to the General techniques section.


Most links in this checklist reside outside ibm.com at the Web Content Accessibility Guidelines (WCAG) 2.0. W3C Recommendation 11 December 2008: http://www.w3.org/TR/WCAG20/

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