A stand-in for film and television is a person who substitutes for the actor before filming, for technical purposes such as lighting and camera setup.Stand-ins are helpful in the initial processes of film and television production. Stand-ins allow the director of photography to light the set and the camera department to light and focus scenes while the actors are absent. The director will often ask stand-ins to deliver the scene dialogue ("lines") and walk through ("blocking") the scenes to be filmed.