How to add sound to amateur films (1954)

If you are accustomed to producing silent films on reversal stock, the above process means appreciable added expense and complication. The system is most appropriate to the production of a large number of final prints because the cost of the two negatives and the cutting copy is considerable. When this cost is spread over a large number of prints, however, the overall cost per print diminishes rapidly and after the first few copies it becomes quite low. The first step in using a negative-positive system is the exposure of the picture on negative stock. This is developed and fixed to provide a negative which, like that from a still camera, has blacks and whites reversed. Consequently, the film which goes through your camera will be of no use for projection. This is in contrast to the reversal film which is normally used by amateurs and which is processed to provide a positive, i.e., a film in which whites are white and blacks, black. Because of this, you can use double perforated film in a 16-mm. camera even though the married print is always made on single-perforated film. You are compelled to use single-perforated film in the camera only if it is a singlesystem sound camera. This records the sound directly on the same film as the picture. The high cost of such a camera places it beyond the reach of most amateurs, however, and in any event it introduces editing difficulties later on. The negative film stock in the camera should be exposed at 24 f.p.s. since the print is projected at this speed. The higher speed provides better sound quality than is possible at 16 f.p.s. It means also that you must open your lens iris by two-thirds of a stop above the aperture you use at 16 f.p.s. Instead of/8 for example, you will use/6-3. The Cutting Copy It is important to keep a reversal film clean. This is especially difficult during editing as you are then obliged to handle the film a good deal and often leave it in short, 56