Prüfschritt 2.3.1 Blitzen, dreimalig oder unterhalb Grenzwert

A flash or rapidly changing image sequence is below the threshold (i.e., content passes) if any of the following are true:

• there are no more than three general flashes and / or no more than three red flashes within any one-second period

• the combined area of flashes occurring concurrently occupies no more than a total of .006 steradians within any 10 degree visual field on the screen (25% of any 10 degree visual field on the screen) at typical viewing distance

where:

• A general flash is defined as a pair of opposing changes in relative luminance of 10% or more of the maximum relative luminance where the relative luminance of the darker image is below 0.80; and where "a pair of opposing changes" is an increase followed by a decrease, or a decrease followed by an increase, and

• A red flash is defined as any pair of opposing transitions involving a saturated red.

Note: The terms "blinking" and "flashing" can sometimes refer to the same content.

"Blinking" refers to content that causes a distraction problem. Blinking can be allowed for a short time as long as it stops (or can be stopped)

"Flashing" refers to content that can trigger a seizure (if it is more than 3 per second and large and bright enough). This cannot be allowed even for a second or it could cause a seizure. And turning the flash off is also not an option since the seizure could occur faster than most users could turn it off.

Blinking usually does not occur at speeds of 3 per second or more, but it can. If blinking occurs faster than 3 per second, it would also be considered a flash.