A script supervisor, sometimes called a continuity script supervisor, has numerous responsibilities before, during and after a film production. His or her main duty is to document every detail surrounding movie scenes as they are filmed. This means everything from the types of lenses used in the cameras to the exact positions of the actors. This person also marks lines through the script to let the director know how many of the film's scenes have been completed, or covered in film speak.
Before production on a film begins, the script supervisor creates reports based on the script to allow for the coordination of all departments. These reports help determine shooting order, which also allows for each department to have their piece of the production ready at the appropriate time. By allowing all parts of a production to work on the same time line, the supervisor helps ensure the continuity of elements such as wardrobe and hair and makeup.
During the actual production of a film, the script supervisor usually remains on the set with the director and technical crew. When each take for a scene is filmed, a special marking device called a clapperboard is filmed in order to sync up the audio and visual elements during editing. A script supervisor is ultimately responsible for insuring that the information on the clapperboard is accurate. This person also records which takes are deemed acceptable by the director.
A script supervisor's day is filled with detailed note-taking, which allows each day of filming to be essentially frozen in time. If a director needs to reshoot scenes, these notes should allow him or her to match the new footage with the existing scenes. Continuity is a difficult element to maintain in a film, so someone who's good at this job must have an eye for detail and the patience to record even the smallest events surrounding a day's shoot.
After the principal shooting has ended, a script supervisor's duties switch to the editing process. Since the director may not be available for editing sessions, the film's editor may work with this person instead. All of the daily notes taken during filming help to organize all of the individual takes. The editor can splice together a complete film based on the director's notes and the script supervisor's careful observations.