clapperboard is a device of hinged boards that are struck
together before filming to synchronize the starting of picture
and sound machinery.
production information to be written to the upper part of
the name of the film
the numbers of the scene and the shot
possible production numbers or codes
clapperboard makes it possible to synchronize the sound and
film material during editing.
the clapperboard is used in the beginning of the take, but
it is also possible to use it in the end; then it is used