Corrected entry: In the movie they show the filming of many scenes in the silent movie. They use a "Clapboard" to start the scene. Granted the slate part was accurate but the clapper was designed for sound use to line up sound with the film, so wouldn't have been used before the advent of talkies.
Vader47000
7th Jun 2012
Correction: Wrong. The filming of silent films are shown using slates that don't have clappers. Clapboard slates are used only in the depiction of what are talkies within the world of the film (such as in the final scene).
Vader47000