Synchronised Sound: Single System
In single-system sound shooting, sound is recorded on a magnetic stripe on the edge of the picture film as it is being exposed in the camera. Magnetically striped stocks are available in negative and reversal forms but nowadays their uses are very limited. Until the introduction of video most television news cameramen used single-system sound because it gave them mobility. You may still find sound stripe equipment in use in a few places, especially if you find yourself working in one of the less prosperous countries, so I will briefly explain how it works in case you find you are presented with a striped master film which you have to edit.
Magnetic stripe sound advance
The intermittent film movement through the picture gate of a camera is controlled by a claw. The claw pulls film down frame by frame. Consequently a sound recording head can not be placed alongside the picture gate as the jerking movement of the film through the gate would make the sound unusable. The sound recording head is therefore placed far enough away from the intermittent movement to obtain a smooth passage of film over its surface. In a 16mm camera designed for shooting and recording on magnetically striped film, the sound head is positioned 28 frames ahead of the picture gate. So, the sound is always 28 frames ahead of the frame to which it refers. This sound advance limits your cutting freedom. Every time you cut you have to remember that the sound for the frame you are cutting is 28 frames further on. Cutting such combined magnetic film needs practice and never offers the creative freedom of cutting with a separate magnetic track in level synchronism.
The magnetic stripe can be transferred on to separate perforated magnetic film. You can then edit it in the same way as with double system sound. Single system shooting is most handy when the original has to be processed and used in a hurry-hence its adoption for television news. The procedure for most normal film making conditions is to shoot double system and make a copy of the camera original for editing, simultaneously rerecording the tape sound on perforated magnetic film ready for cutting.
Single system shooting
Shooting on magnetically striped film stock (A). The processed film can then be edited using the magnetic striped sound (B). The sound will be 28 frames ahead of the picture and this can make cutting difficult (E). Alternatively you can have the magnetic stripe re-recorded on separate perforated magnetic film (D) and the processed original printed to make a mute cutting copy (C). You can then ignore the stripe track and cut in level synchronisation.