Editing Countdown (section)

==Film==
[[File:Eight (film start) cropped2.jpg|thumb|Newer (1959) SMPTE countdown on the head leader of a film reel]]
At the start of films, a countdown sequence is printed on the [[Film leader|head leader]], and is used to synchronize film reel changeovers (switching between reels of film). In film (but not television) the 'Academy Leader' countdown first used in 1930 is in units of feet rather than time units; it starts at 11 and ends at 3 where it cuts to black for the last few feet. In 1959, SMPTE leader was created and measures seconds, not feet. It starts at 8 and cuts to black on the first frame of 2, which is accompanied by a 'pop.'  This leader eventually displaced the older Academy and was the only leader used by the end of the optical (film) projection era.{{citation needed|date=May 2020}}