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HIERARCHY OF COLOR USAGE GUIDELINES

On This Page:  • Finding the Information  • Reading the Information  • Understanding the Information • Other Important Considerations

This page presents a structured hierarchy of color usage guidelines. It starts at the top level with general statements of required cognitive performance and proceeds toward more specific graphics requirements and recommendations that help achieve the top level goals. Where possible links point to related material elsewhere on the Color Usage Website.

To succeed in using an information interface the user must

a) find the needed information
b) read it, and
c) understand it.

Finding the Information Back to the top of the page.

1. The graphics shall allow the user to find desired information with little cognitive effort under all operational conditions.

1.1 Graphic representations of more urgent (critical, important) information shall be more salient than those of less urgent (critical, important) information, under all operational conditions.
More about salience manipulation.

1.1.1 Temporal modulation (flashing, blinking, motion) shall only be used to call attention to urgent conditions requiring immediate attention or action.
More about temporal modulation.

1.1.1.1 Temporal modulation shall distract from other important information as little as possible.

1.1.1.1.1 Less distracting forms of temporal modulation shall be used if adequate.
More about temporal modulation.

1.1.1.2 Only small screen areas shall be temporally modulated.

1.2 Color* codes intended to distinguish different classes of operationally critical data shall be discriminable under all operational conditions.
More about color discrimination.
More about reflected light.
*Denotes a guideline sufficiently general that the word "graphic" may be substituted for the word "color".

1.2.1 Data objects to be coded by colors shall be large enough to allow color discrimination under all operational conditions.
More about color discrimination.

1.2.2 Color codes of symbols (or text) shall be discriminable on all possible backgrounds under all operational conditions. More about color contrast.

1.2.3 Since Section 508 presumes that the user population includes users with deficient color discrimination, all color coding shall be used redundantly with other graphic codes.

1.2.3.1 Since Section 508 presumes that the user population includes users with deficient color discrimination, caution and warning color coding (red, yellow, green) shall be used redundantly with other graphic codes.

1.2.3.2 Since Section 508 presumes that the user population includes users with deficient color discrimination, color codes shall be discriminable by the largest classes of color deficient users.
More about individual differences in color vision.


Reading the Information Back to the top of the page.

2. Graphic representations of all operationally critical information shall be legible under all operational conditions.
More about legibility.

2.1 All possible combinations of colors of symbols (or text) and their backgrounds shall have sufficient luminance contrast to be legible under all operational conditions.
More about luminance contrast.
More about reflected light.

2.1.1 Use of blue or yellow symbols or backgrounds shall have sufficient luminance contrast to be legible under all operational conditions.
More about blue.
More about outlining and infills.

2.2 If textured backgrounds are used, symbols (or text) shall be legible on all possible backgrounds, under all operational conditions.
More about pattern masking.

2.3 All symbols (or text) shall be large enough and have broad enough strokes to be legible under all operational conditions.


Understanding the Information Back to the top of the page.

3. When the desired information has been found and read, the colors* shall allow the user to understand the information with little cognitive effort and minimum risk of error under all operational conditions.

3.1 Color* codes intended to identify different classes of operationally critical data shall be identifiable under all operational conditions.
More about color discrimination and recognition.
More about reflected light.

3.1.1 The number of distinct color* codes intended to identify different classes of operationally critical data shall be small enough to allow adequate identification performance under all operational conditions.
More about color discrimination and recognition.

3.1.2 Color codes of symbols (or text) shall be identifiable on all possible backgrounds under all operational conditions.

3.1.2.1 Use of saturated background colors shall not cause misidentification of color codes of symbols (or text).
More about color contrast.
More about outlining and infills.

3.2 Color* codes shall be used consistently throughout the work environment.

3.2.1 Each color* code shall be used to code only a single data category throughout the work environment.

3.2.2 Each data category shall be coded with only a single color* code throughout the work environment.

3.3 Color* codes shall be consistent with existing cultural conventions.

3.3.1 If cautions and warnings are represented in the system, red shall be used only to code data related to a warning.

3.3.2 If cautions and warnings are represented in the system, yellow (or amber) shall be used only to code data related to a caution.

3.3.3 If cautions and warnings are represented in the system, green shall be used only to code data that have been evaluated for safety status and determined to be in neither a caution nor warning status.

3.3.4 Color* codes of operationally critical data shall be consistent with existing conventions of related applications.


Other Important Considerations Back to the top of the page.

4. Color shall be used sparingly and only for specific operational purposes.
More about labeling with color.
More about grouping with color.
More about color and popout.

4.1 Color shall not be used for decorative purposes.


Related Topics:
go to this page
Introduction to Color Guidelines
go to this page Guidelines for Color Discrimination and Identification
go to this page Luminance Contrast Color Guidelines
go to this page Other Color Design Guidelines
go to this page Color Guidelines Bibliography



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