What is a Clapperboard?

Mary McMahon
Mary McMahon

A clapperboard is a device used in film, television, and advertising production to assist with the process of synchronizing the sound and film recordings. Because sound and film are usually recorded separately, they must be matched carefully during the editing process, or the resulting production will feel slightly off to viewers. When the synchronization is extremely poor, it may become almost comic, but even small discrepancies can be very disorienting for viewers.

The sound of the clapper is used to synchronize the sound with the filmed scene.
The sound of the clapper is used to synchronize the sound with the filmed scene.

There are two components to a clapperboard: the clapper, and a slate. The clapper consists of two pieces of wood or plastic which can be snapped together to make a distinctive clacking noise which is easy to find on the sound recording. By matching the sound of the clack to the physical action on the film, the editor can synchronize the sound and film recordings. Clapperboards are sometimes also given away as mementos of film productions.

The slate is used to record information about the production, including the name of the production, the director, the director of photography, and the scene. The take number and camera angle are also written out on the slate. This information assists people in the editing room, allowing them to quickly know what they are looking at by reading the clapperboard.

To use a clapperboard, the film crew sets up the scene, writes out the information on the clapperboard, holds up the clapperboard, and then turns on the camera. Usually, the information on the slate is read out, and then the clapper is snapped. After this, the actors can start performing. The sound on the set is picked up and recorded onto one device, while the film of the scene is stored in the camera.

Clapperboards don't necessarily have to be clacked to mark a scene. Some moviemakers use digital slates, in which a timer is synchronized with the camera. When the clapperboard is held up at the beginning of the scene, the camera records the time on the board, allowing the editor to find the same point in the film or digital recording to synchronize with the sound later.

All of the information on the clapperboard is also recorded in the continuity book for the production, so that people on the crew and in the editing room can look up details later. For example, an editor who wants to find a specific scene to work on could check the continuity book to find out where it should be located.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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Discussion Comments


Its funny how many people know about clapperboards. They have become one of the defining images of film making, kind of like the folding directors chair and the mounted boom mike. Almost any depiction of film making includes a scene where someone holds a clapperboard expectantly waiting for the director to call action and then slamming down the clapper.


This is just one example of all the things that go on behind the scenes when you are making a movie. Most people know about lights, cameras and sound equipment, but there are dozens of other technical jobs that must be done perfectly if a movie is going to look good on screen.


I remember seeing a kung fu film once that had absolutely horrible synchronization. The dialogue was at least 3 seconds behind the action on the film. This meant that characters mouths would move long before any sound came out. Obviously they need a better clapper board. This seems to be a problem in a lot of those old kung fu movies.

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