Explanation

A colorDependent access mode indicates that color is the sole means of conveying some visual information. It is expressed in metadata using the colorDependent value.

As colorDependent describes a characteristic of visual content, it is considered a modifier of the visual access mode value and you should always pair the two values together.

A common example of the need to perceive color occurs with graphs and charts. If the bars in a graph, or the slices in a pie chart, are differentiated by color alone, then users may not be able understand the data unless they can perceive those color differences.

Color dependence can also manifest itself in other ways, such as when learning assignments are color coded to age or difficulty level, or when hyperlinks are colored to indicate their purpose (e.g., to open external web sites).

The application of the colorDependent value only applies to the visual reading experience and the value is not set if a secondary means of differentiating the information is available. If, for example, graphs and charts include distinct patterns in their data representations, such as lines going in different directions, then a user can use those patterns to differentiate the data. Similarly, hyperlinks can use different types of underline to gives a visual cue to their existence and purpose.

Note, however, that any secondary means of differentiating the information must also be visual before this label can be omitted. Affordances provided for non-visual readers, such as through hidden ARIA attributes, are not generally accessible to visual readers so do not improve the accessibility for them.

The colorDependent value is meant to help individuals with, for example, color blindness and cognitive disabilities determine if the content will be accessible to them. Whether affordances are provided that non-visual readers to access visual presentations is declared through the sufficient access modes.

A colorDependent access mode is common in publications produced using the EPUB format but is less common for audiobooks. It is only potentially relevant when an audiobook also contains supplementary material beyond the audio.

Examples

Example 1 — EPUB 3
<meta property="schema:accessMode">visual</meta>
<meta property="schema:accessMode">colorDependent</meta>
Example 2 — EPUB 2
<meta name="schema:accessMode" content="visual"/>
<meta name="schema:accessMode" content="colorDependent"/>
Example 3 — Audiobooks
"accessMode": ["auditory", "textual", "colorDependent"]

ONIX Mapping

The colorDependent value does not currently have an ONIX equivalent.

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