In this post, I want to write not about a prop, but rather about an interesting piece of equipment used on sets: the clapperboard.

The clapperboard is the black slate seen at the beginning of a scene, with a clapper on top. It is often seen in the bloopers bonus section of a DVD movie. In addition to its obvious usage to identify scenes and takes, the clapping sound is used as a clue to synchronize audio tracks with video.

In the very beginning of cinema, the clapper and the slate were two separate devices. Then someone had the great idea to put the two devices together so that it could be operated by a single person.

Decades later, the clapperboard got an overhaul by adding an LED display. As can be seen in Matthew L. Davies US patent number 6831729, the electronic version does more than just displaying time on a red digital readout. The digital clapperboard has microprocessors and communication ports, sending sync signals. Therefore the clapper on a digital slate is no longer needed. Some models do have a clapper for nostalgia and tradition.