For once, Wikipedia’s definition is best: “Picture lock is a stage in editing a film or editing a television production. It is the stage prior to online editing when all changes to the film or television program cut have been done and approved. It is then sent to subsequent stages in the process, such as online editing and audio mixing.”
Ladies and gentlemen, I have reached picture lock on Pause of the Clock.
In three days I’ll be making an important announcement about the film, so stay tuned!