An animation that flashes at less than two flashes per second is acceptable.
People who have photosensitive epilepsy can have seizures triggered by flickering or flashing.
Be aware of documents that might have flashing or blinking elements:
- PowerPoint presentations might have flickering or blinking animations, or video clips.
- E-mail attachments can be in many formats including video clips.
- Web Pages can include animated text or video clips.
- Microsoft Word documents can have animated text.
It is wise to avoid flashing or blinking elements completely, unless you know your audience doesn't include people with a seizure disability. If you feel that it is essential that your documents have a flashing or blinking element, make sure that you warn your readers so that they can avoid it. And supply the information in another format.
Note The frequency of flashing that causes seizures is between 2 and 55 flashes per second (Hertz). But this can be difficult to determine in a practical situation; for instance, flicker and refresh rates on a monitor are all factors in the rate of flashing. Therefore, it is best to follow the above advice.