International projectionist (Jan 1943-Dec 1944)

ION AL PROJEG VOLUME XVIII NOVEMBER 1943 NUMBER 11 Film and Apparatus for 16-mm Projection PROJECTION of 16-mm films for entertainment, which seems likely to become a husky little brother of the industry after this war, involves peculiarities of film and equipment unknown to the 35-mm field. Some of these dif■ ferences relate to the smaller dimensions of the 16-mm film, while others relate to the difference in the stock, for cellulose acetate is used almost exclusively; and it is not as dangerous and does not call for the same precautions as the nitrate stock used for 35-mm film. Still other outstanding differences relate to the commercial history of the smaller film, which up to the present has involved great emphasis on portable equipment with the result that many apparatus features reflect the pressure for compactness and light weight, even in systems not designed to be portable. It will be noted that on 16-mm sound film there is only one row of sprocket holes. The silent 16-mm film had two rows, but one had to be sacrificed to get space enough for a sound track of acceptable width. Correspondingly, 16-mm sound sprockets have teeth on one side only, and intermittent motion also is imparted to the film by pulling at one side only. Results, however, are surprisingly more satisfactory than could be obtained by applying the same practice to 35-mm stock, largely because everything about 16-mm is smaller and lighter. The reel By AARON 1SADELL in the upper magazine weighs less, and less force need be applied by the pulldown sprocket. The length of film held under tension in the gate is shorter, and therefore offers less resistance to the intermittent action. Another factor of importance in this connection is that the stock is less than half the width of theatre film; it is naturally easier to move a narrow film by pulling at one side only than to move a wide film by pulling it the same way. The speed of operation is 24 frames per second, as with standard film, but the speed of the film is slower, the frames being smaller. Film moves at the rate of 36 feet per minute, instead of the standard rate of 90 feet per minute. There are 40 frames (and 40 sprocket holes) per foot of film; thus the rate of projection is 1440 frames per minute — or. as said, 24 per second. The sprocket An outline is presented herein of the special features of 16-mm film and equipment, with particular emphasis on the differences between them and their 35-counterparts. A flourishing field of activity before the war, 16-mm holds out every promise of vastly increased importance in post-war days. It offers the projectionist new opportunities and is a development not to be ignored. holes are placed one at each dividing line. Because the film moves more slowly, it. is possible to get more playing time on a reel of given size. The reels shown in Figure 1, for example, hold enough film for 100 minutes — the equivalent of a full-length feature picture. With such equipment, it would be possible to rethread while curtains are closing and reopening, and thus run an entire show with only one projector and no changeovers. Figure 1 also dramatically illustrates some of the precautions that are not taken with 16-mm film. There are no magazines, for example. The mechanism is uncased, a practice abandoned many years ago as too dangerous for nitrate stock. Fire-proof film cabinets and special shipping precautions can be omitted. Acetate compounds burn — this film can be set afire. But whereas nitrate compounds, when burned, release oxygen to prolong and intensify their own combustion, acetates do not do this, but tend if anything to release carbon dioxide which retards combustion. The nitrate stock, however, has other and different advantages over acetate, which have always prevented acetate coming into widespread use for 35-mm projection, where the utmost in quality of results is the first consideration. A 16-mm projection gate is shown in Figure 2. The upper sprocket, with teeth at one side only, and the relatively NOVEMBER 1943