Explanation

The flashing values is used to indicate that there is content in the publication that flashes more than three times a second or that the flashing is below the general flash and red flash thresholds.

These flashing hazards can cause headaches and seizures for users who are photosensitive.

Although videos are often recognized as a source of flashing hazards (e.g., strobe effects), there are many types of content that can present a flashing risk (e.g., animated graphics, and scripted games and images).

The content that presents a hazard should be noted in the accessibility summary.

The flashing value must never be set together with the none, unknown, noFlashingHazard, or unknownFlashingHazard values, as these values conflict.

Examples

Example 1 — EPUB 3
<meta property="schema:accessibilityHazard">flashing</meta>
<meta property="schema:accessibilityHazard">nomotionSimulationHazard</meta>
<meta property="schema:accessibilityHazard">noSoundHazard</meta>
Example 2 — EPUB 2
<meta name="schema:accessibilityHazard" content="flashing"/>
<meta name="schema:accessibilityHazard" content="nomotionSimulationHazard"/>
<meta name="schema:accessibilityHazard" content="noSoundHazard"/>
Example 3 — Audiobooks
"accessibilityHazard": [
   "flashing",
   "nomotionSimulationHazard",
   "noSoundHazard"
]

ONIX Mapping

The flashing value maps to ONIX list 143 code 13 ("Flashing hazard").

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