Mark It

The Call for Synchronization

‘Mark it!’ is a key command in the universal ritual that initiates every take on a professional film set. This instruction, typically given by the First Assistant Director (1st AD), is a cue for the Second Assistant Camera (2nd AC) to step in front of the lens with the film slate (or clapboard). The subsequent ‘clapping’ of the slate’s sticks creates the ‘mark’—a single, precise point of reference that is essential for synchronizing the separately recorded picture and sound in post-production. It is a simple action, but it is one of the foundational pillars of the dual-system sound recording process that has defined cinema for nearly a century.

The Slating and Rolling Sequence

The ‘mark it’ command occurs within a strict and efficient sequence designed to ensure all departments are ready and recording:

1. The 1st AD calls ‘Quiet on set!’ to cease all activity.
2. They then call ‘Roll sound!’ The sound mixer starts recording and confirms by saying ‘Sound speed!’
3. The 1st AD calls ‘Roll camera!’ The camera operator starts recording and confirms with ‘Camera speed!’
4. With picture and sound now recording, the 1st AD calls ‘Mark it!’
5. The 2nd AC, already in position, states the scene and take number for the camera and microphone (e.g., ‘Scene 12, Take 5’) and then brings the clapper sticks together with a sharp, clear ‘clap.’
6. The 2nd AC quickly exits the frame, and the director then calls ‘Action!’

The Dual Purpose of the Mark

The slate and its ‘mark’ serve two vital functions. First, the visual information written on the slate—scene number, take number, director, DP, etc.—provides a clear point of identification for the editor when they are sorting through hours of footage. Second, and most critically, the ‘mark’ is the synchronization point. The editor can see the exact frame where the two sticks make contact and can see the corresponding audio ‘spike’ on the sound waveform. By aligning these two points, the separately recorded sound is perfectly locked to the picture for the remainder of the take.