The traditional movie marker has a hinged "mouth," which is clapped at the start of each scene. The marker gives crucial information such as the movie title, director, director of photography, producer, film company, scene number and take number. During the editing process, editors might be looking at as many as hundreds of hours of film, with each take unique.
Traditionally, American films sequence the numbers on the marker, with the scene number, then the camera angle and then the take number. It might look like this: scene 120, D, take 21. Since American film industry produces so much of the volume of movies, this sequence has also been adopted elsewhere. Sometimes, American independent films use a unique pattern.
In European films, a different sequence is employed. The slate number is first, followed by a combination of the take number and the camera angle. Before a specific scene, the same marker would read slate 121, take 21D. Some countries vary the pattern, and American film crews adopt the American pattern while filming in Europe.
Invented by Matthew L. Davies, the high-end, electronic clapperboards, known as "smart slates," feature LED screens that mark the SMPTE time code. SMPTE stands for the Society of Motion Picture and Television Engineers, and its timecode has become the standard in the field. The clapperboard is a blend of the traditional marker, with a hinged mouth and handwritten information about the director and date. These "smart slates" are increasingly used in major motion pictures.
Movie markers help in the editing process. If the writing is not clear enough or if the numbers are misplaced, the editor can be seriously hampered by these errors. All film crews should be prepared for problems, especially when depending on "smart slates" or other electronic devices. Not only does the writing an information need to be correctly written, but the board needs to be clapped loudly enough to be caught on the external recorder and the camera.