2.3.1 Three Flashes or Below Threshold
High-Level Description
Content must not flash more than three times per second unless below threshold values.
Detailed Description
What this means
- Content that contains flashing content such as videos or animations flash no more than 3 times per second. Content should avoid flashing content entirely or the flashes should be below the threshold levels.
- Flashing content can distract, cause seizures, or sensory overloads for some users.
Indicators of Non-Compliance:
- Animations or videos that flash rapidly (more than three flashes per second).
- Red or high-contrast flashes that exceed threshold levels.
Real-World Examples
| Scenario | Non-Compliant | Compliant |
|---|---|---|
| A Video | A video that has scenes that contains flashing content and the content flashes more than 3 times a second | A video that contains non flashing content or is below the threshold of 3 times a second |
| An Alert | There is an alert that pops up that constantly blinks | An alert that pops up and does not blink, or if it is blinking, it stops after a short period of time or there is a mechanism to stop the blinking |
| An animated logo or animated image | A logo or an animated image such as a GIF that blinks/flashes | The logo or animated image doesn't flash/blink at all. If they do flash/blink, it is for a short period of time, or there is a mechanism to stop it from flashing/blinking |
Disability Impact
| Disability Group | With Excessive Flashing | With Non-Flashing Content |
|---|---|---|
| Photosensitive disorders such as photosensitive epilepsy | Flashing content can trigger seizures | Users can safely access content and media without risk of triggering seizures |
| Neurological or cognitive disability | Flashing content can cause sensory overload and or disorientation | Users are less likely to become disorientated or burdened by sensory overload when browsing a website |
Supporting Documentation
Remediation Strategies
1 - Avoid flashing content
Make sure all media and website content contains no flashing or if there is flashing, it is below the threshold levels
2 - Use video editing tools to check flash thresholds
Use your video editing software to check the thresholds of all video content are below the threshold of less than 3 flashes per second
3 - Testing tools like the Photosensitive Epilepsy Analysis Tool (PEAT)
Use Software like PEAT to check your content to make sure it meets the threshold