Note 2 See also blinking . focus indicator [New] pixels that are changed to visually indicate when a user interface component is in a focused state functionality processes and outcomes achievable through user action general flash and red flash thresholds 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; or 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 (1.0) 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 Exception: Flashing that is a fine, balanced, pattern such as white noise or an alternating
      checkerboard pattern with "squares" smaller than 0.1 degree (of visual field at typical
      viewing distance) on a side does not violate the thresholds. Note 1 For general software or Web content, using a 341 x 256 pixel rectangle anywhere on the displayed screen area when the content is viewed at 1024 x 768 pixels will provide a good estimate of a 10 degree visual field for standard screen sizes and viewing distances (e.g., 15-17 inch screen at 22-26 inches). This resolution of 75 - 85 ppi is known to be lower, and thus more conservative than the nominal CSS pixel resolution of 96 ppi in CSS specifications. Higher resolutions displays showing the same rendering of the content yield smaller and safer images so it is lower resolutions that are used to define the thresholds.