Examples of Flickering Images

Guideline 7.1 of the W3C's Web Content Accessibility Guidelines warns against any practice that makes the screen flicker between 4 and 59 Hertz (Hz). Similarly, the Section 508 regulations warn against any flickering between 2 and 55 Hz.

A Hz is defined as "one cycle per second". To determine the exact number of Hertz for an item in question, it is recommended that specialized tools be used. However, as a point of reference, the following page contains images that flicker at 4Hz, 7Hz, 20Hz, and 59Hz.

Examples of Flickering Images

If you have photosensitive epilepsy, do not follow this link to the flickering images demo.