Film Terminology: clapperboard
In the world of film-making, audio and video are recorded separately. The clapperboard is a device that allows sound and vision to be synchronised during the editing stage.

The clapperboard is a simple device: a blackboard, ('slate'), the size of large book with a smaller section along the top, attached by a hinge at one end. A black and white chevron pattern denotes where these two pieces meet. In addition, there is room for information relating to the scene being shot, such as the film title, the name of the scene and the 'take' number.

The clapperboard is used at the beginning of a scene: Once the camera and sound recorder are running and up to speed, the director will say something like '..and mark it'. The clapperboard operator then holds the board in front of the camera, opens it up, reads the information from the board so that it is picked up by the microphone and 'claps' the two pieces of the clapperboard together. This creates an event that is readily identifiable on both film and tape. Additionally, using the clapperboard at the end of the scene allows compensation for small variations in recording speed between sound and vision.