VHA Section 508
Color and Contrast
Using color has the benefit of making content easier to understand and read in some cases.
Color can enhance content and be accessible when it is used properly for the entire
audience. There are two areas authors need to be aware of when using color. Authors need
to ensure there is a big color difference between foreground and background text and
images. A stark contrast between colors makes text and images of text easier to read.
Authors also need to be aware of not using color to convey meaning. Any important
information denoted through color needs to be available through text as well. These
concepts will be discussed in more detail in this tutorial.
Important: When using images, tables, charts and graphs or any other object that was
produced in another application it is recommended that the object be updated from within
the source application (i.e. Excel, PowerPoint, Photoshop, etc.). Trying to update content
using Word that was not originally produced in Word may not result in the desired effect.
Moreover, it is important to update content in its source application because then the
content can be used elsewhere and already be 508 compliant.
Providing Contrast between Colors
The groups that are largely affected by color contrast are those with low vision and color
blindness. Information may be misinterpreted when the color contrast is not sufficient
enough for users to accurately read the content. Plenty of contrast needs to be present
between foreground and background colors. If multiple colors are used in either the
foreground or background the opposite layer needs to accommodate all colors.
There must be enhanced contrast between the foreground text and background colors and
images of text. This requirement applies to text over solid backgrounds, decorative
backgrounds and images that contain text. Many color contrast analyzer tools are available
to test contrast ratios. Tool information is available under the heading “Color Resources” on
the VHA Section 508 Resources page. The standard for text less than 18 point or less than
14 point if bolded must have a contrast ratio of 4.5:1 or more. For text 18 point or larger or
14 point if bolded, the contrast ratio must be 3.0:1 or higher. It is best to avoid using busy
background images behind text. When there is less conflicting content it is easier to achieve
appropriate contrast levels. When complex background images, watermarks or colors must
be used, provide a halo of sufficient size around the text that provides sufficient contrast for
the foreground text color.
Note: Text or images of text that are part of inactive user interface elements, part of a logo
or brand name, pure decoration, content not visible to anyone, or that are part of a picture
that contains significant other visual content are not required to have sufficient color