Explanation

A chemOnVisual access mode indicates that a publication contains images of chemical equations and formulas. It is expressed in metadata using the chemOnVisual value.

As chemOnVisual 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.

It is not uncommon to pair chemOnVisual with colorDependent if color perception is the only way to differentiate information (e.g., if relationships are color coded).

It is sometimes also paired with textOnVisual if text content beyond the equation or formula data itself is also encoded in the image (e.g., if relationships or descriptions are drawn as text in the image canvas).

Note that chemistry represented using a text-based markup language like MathML, or a formatting language like LaTeX, is considered a textual access mode.

A chemOnVisual access mode is common in publications produced using the EPUB format as there is no support for rendering chemical markup languages like ChemML. It is only potentially relevant to audiobooks if there is supplementary material beyond the audio.

Examples

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

ONIX Mapping

The chemOnVisual value maps to list 81 code 47 ("Chemical content").

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