About

Version: WCAG 2.0+
Number: 2.3.1
Level: A
Applicability:
  • Animations
  • Video
Requirement:

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.

Guidance:

Purpose

The purpose of this success criterion is to ensure that photosensitive readers are not put at risk of seizure when reading digital publications.

How to Meet

If authors include video, animated images or applications, or other content that flashes more than three times in a second, they need to ensure that the content is safe for photosensitive readers.

Content that flashes more than three times per second must meet the general and red flash thresholds. Testing for conformance will normally require specialized software.

Note that if the video or image that flashes occupies an area that is 21,824 square pixels or less, it passes this success criterion. Below this size, the flashing will not impact users.

Additional Information

The following knowledge base pages provide more information about how to address this success criterion for publishing content: