Content flash

Back to the a11y checklist

Why it matters

Flashing or blinking content can cause seizures in people with photosensitive seizure disorders, particularly if it flashes more than three times in one second, covers a large enough area of the screen, and is bright enough.

Example

A video or animation with flashing content needs to be edited so that the flashing part only flashes three times in any one second period.

WCAG 2.0 reference: 2.3.1 Three Flashes or Below Threshold

How to check for this

1. Use a tool to determine that neither the general flash nor red flash threshold were exceeded Manual Automated

Collaborators

• Designers
• Product Owners
• Video providers

Resources

• Keeping the flashing area small enough
• Ensuring that no component of the content flashes more than three times in any 1-second period
• Using a tool to ensure that content does not violate the general flash threshold or red flash threshold