“Pages shall be designed to avoid causing the screen to flicker with a frequency greater than 2 Hz and lower than 55 Hz. – §1194.22(j)

Why it matters

Absent movies, flickering effects are unusual in PDF files.

While it’s possible to create a flickering effect using JavaScript, there’s little or no practical application for such scripts.

EXAMPLE: Animated text produces a strobing effect.
RESOLUTION: Ensure flickering text and images are removed. 

This checkpoint is primarily aimed at embedded movies but could apply to certain types of scripts.

What happens when I verify this Checkpoint?

This checkpoint prompts the user for a PassFail or Not Applicable judgment whenever an element (movie or script) in the document is found that could possibly cause the screen to flicker. The checkpoint will automatically be set to ‘not applicable’ if no element is found that could possibly cause the screen to flicker.

When to Pass or Fail this Checkpoint?

PassThe movie or script causes flickering but not with a frequency greater than 2 Hz or lower than 55 Hz.
FailThe movie or script causes flickering with a frequency greater than 2 Hz or lower than 55 Hz.
RemediationTypically, removal and/or replacement of the movie or script with a non-flickering version.

 

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