Picture lock is a stage in editing a film or editing a television production. It is the stage prior to on-line 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. Any last minute changes can force portions of subsequent work to be re-done.
Not every production necessarily obeys picture lock. A director or executives in charge may change their minds and ask for additional changes to be made.