Color and Contrast

ISSUE:

The grouping or conveying of information through the use of color alone may be difficult or impossible to access for a user with a visual impairment or who is color-blind. Conversely, the use of color may be an effective means of conveying information to a user with a text-processing impairment or other learning disability. Using redundant indicators (i.e., color, Text, layout, shape/texture and audio) will reduce errors for all users and provide access for users with a variety of impairments.

STANDARD:

Provide redundant indicators (e.g., Text, layout, shape/texture and audio) for color identifiers, alerts/warnings, prompts or feedback.

Provide color combinations of significant brightness and contrast.

Optimal color combinations for individuals with color vision anomalies:

FOREGROUND	BACKGROUND	SAMPLE
Black	White	Black on White
White	Black	White on black
black	Yellow	Black on Yellow
Yellow	Black	Yellow on Black

Color combinations that should be avoided:

FOREGROUND	Background	SAMPLE
Blue	Black	Blue on black
Purple	Black	Purple on black
Red	Black	Red on black
Green	Black	Green on black
Green	Red	Green on Red
Red	Green	Red on Green
Red	Blue	Red on blue
Blue	Red	Blue on Red
Yellow	White	Yellow on White
Orange	White	Orange on White
White	Yellow	White on Yellow