Three Flashes or Below Threshold
Summary:
WCAG 2.3.1, "Three Flashes or Below Threshold," is designed to protect users from content that could potentially cause seizures due to flashing or blinking elements. This guideline is particularly important for ensuring the safety and well-being of users with photosensitive epilepsy.
What:
This criterion mandates that web pages do not contain anything that flashes more than three times in any one-second period. It aims to prevent content from containing flashes at a rate that is known to induce seizures in susceptible individuals. The key points of this guideline are:
- Flashing Content: Web content must not flash more than three times per second.
- Safe Threshold: Keeping flashing below the specified threshold reduces the risk of triggering seizures.
Why:
Flashes, especially those in certain frequency ranges, can cause seizures in individuals with photosensitive epilepsy. By limiting or eliminating such flashes, this guideline makes web content safer for those individuals, ensuring that the web remains an inclusive space.
Examples and Scenarios:
- Avoiding Flashy Animations: Animations or video content should be designed to ensure they do not flash or flicker rapidly.
- Banner Ads: Banner ads, often used on websites, must not flash rapidly to attract attention.
- Social Media Content: Content shared on social media platforms, including GIFs and short videos, should adhere to this flashing limit to ensure user safety.
How to Comply:
- Websites: Monitor and control the flashing rate of all visual content, including videos, animations, and interactive elements, to ensure they do not exceed the three flashes per second threshold.
- Mobile Apps: Design app interfaces and content, such as splash screens or notifications, without rapid flashing or blinking elements.
- Software Applications: Review and adjust any graphical elements, animations, or video content within the application to adhere to the safe flashing threshold.
Exceptions:
- Essential Flashing Content: If flashing is essential for communication or functionality and cannot be done within the safe threshold, then it's important to provide warnings and alternatives for users who might be affected. However, such cases should be extremely rare and handled with caution.