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2.3.1 Three Flashes or Below Threshold [Level A]

Description

Three Flashes or Below Threshold

2.3.1 Web pages do not contain anything that flashes more than three times in any one second period, or the flash is below the general flash and red flash thresholds. (Level A)Understanding Success Criterion 2.3.1

Note: Since any content that does not meet this success criterion can interfere with a user's ability to use the whole page, all content on the Web page (whether it is used to meet other success criteria or not) must meet this success criterion. See Conformance Requirement 5: Non-Interference.

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Sufficent Techniques

Sufficient Techniques for 2.3.1 - Three Flashes or Below Threshold

Note: Other techniques may also be sufficient if they meet the success criterion.

  1. G19: Ensuring that no component of the content flashes more than three times in any 1-second period

  2. G176: Keeping the flashing area small enough

  3. G15: Using a tool to ensure that content does not violate the general flash threshold or red flash threshold

Advisory Techniques

Advisory Techniques for 2.3.1 - Three Flashes or Below Threshold

  • Reducing contrast for any flashing content (future link)

  • Avoiding fully saturated reds for any flashing content (future link)

  • Reducing the number of flashes even if they do not violate thresholds (future link)

  • Providing a mechanism to suppress any flashing content before it begins (future link)

  • Slowing down live material to avoid rapid flashes (as in flashbulbs) (future link)

  • Freezing the image momentarily if 3 flashes within one second are detected (future link)

  • Dropping the contrast ratio if 3 flashes within one second are detected (future link)

  • Allowing users to set a custom flash rate limit (future link)

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Failures

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Notes

Use the Photosensitive Epilepsy Analysis Tool (PEAT) to evaluate this SC.

 

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