Moving Picture Age (Jan-Dec 1922)

May, 1922 MOVING PICTURE AGE 19 or slow-burning film, are provided with fireproof cases. In some instances the film is contained in fireproof magazines that fit inside the carrying case, while in others a fireproof partition is employed between the driving motor and the lamp house. In still other suitcase projectors no interior fireproof magazines or partitions are employed, as the designers have felt that these are unnecessary. That the danger of fire has been reduced to a minimum in many of the portable or suitcase projectors is evident from some of the tests that have been conducted along these lines. The manufacturer of one of these machines in recent tests before state fire officials demonstrated that it was impossible to ignite the film, even when the automatic fire shutter was removed. When the light was finally forced so as to ignite the film, only one frame of the reel could be burned. The snubbers on the film shoe, as well as the snubber tube and the additional fire guard with which this particular projector is provided, prevented a spreading of the conflagration beyond the source. Guards that prevent the film from coming in contact with any place that permits of any chance of fire are also provided on this particular machine, as well as in many other of the offerings in this class. In another convincing test a thousand-foot reel of inflammable film was ignited with a match inside of the projector, and the door was closed. The film smoldered, but at no time did open flame appear on the outside of the projector case. During these tests the machine was picked up and carried about while the film was burning inside the case. This refutes the generally prevalent belief that films when ignited are explosive. Films by themselves are not explosive. Under certain conditions, where the film has been ignited but is decomposing rather than burning with a flame, in a closed space, it generates certain gases that, when mixed with air, may prove explosive. But films, by themselves, are not explosive, nor are they spontaneously combustible. So the portable or suitcase projector is now designed and constructed so that the fire hazard is reduced to a minimum. In a number of offerings the optical system has been arranged in such a manner that it is virtually impossible to ignite the film even if it is left absolutely still in the full light of the lamp house. This is accomplished by the use of certain lenses or by a special water-cooled condenser. Again, in some offerings a special form of lamp is employed that has a minimum of heat for the maximum light on the screen. Then again, there is much slow-burning film of standard width now available, and in time probably all our films will be of that kind. All present-day portable or suitcase projectors are provided with electric motor drive, and with a hand drive in case of emergency. The motor drive is controlled by a simple switch for starting and stopping, and also with a rheostat so that the speed may be varied. In many offerings the motor drive is reversible, in order that the film can be run backward or even rewound in this manner. The question of threading and the general accessibility of the operating parts is an important consideration in considering a portable or suitcase projector. Some machines are not as convenient as they might be, but for the most part the designers of late have given a good deal of thought to this phase of the machine and their models reflect good judgment. Indeed, some of the offerings have the case arranged so that it opens up on two or three sides so as to give the maximum accessibility, and in at least one offering the mechanism is mounted in such a manner that it can be swung out clear of the case for re-threading and general inspection. Most machines of this type have the film reels side by side, since this arrangement makes for compactness. In the earlier models, before the designers fully appreciated how the film could be twisted in order to use side-by-side reels, it was not uncommon practice to mount the reels one above the other, making a very tall machine and one truly resembling the usual suitcase. The present scheme of placing the reels side by side makes necessary a rather elaborate threading of the projector, but this is well worth while in view of the compactness. A few offerings make use of a hinged magazine which can be swung up and out of the case in order to give a straight feed for the film, with one reel above the other, so that the threading and operation can be simplified. It is a matter of choice whether this arrangement is employed in preference to the usual side-bv-side plan. The usual machine of this general class is intended for use on 110 or 220-volt direct or alternating current. By using the universal type of motor it is possible to use the machine interchangeably on either kind of current. However, for use where commercial current does not exist the machines are obtainable in special voltages to be operated with The Acme Projector isolated power plants, or in conjunction with a special generator that is driven by the automobile power plant. In some cases the generator is driven off the engine shaft by means of a gear-andchain drive, while in others it is mounted on the running-board and driven by means of a belt off one of the rear wheels, which have been jacked off the ground. This source of power permits the portable projector to be used anywhere, especially for outdoor shows. Aside from the strictly suitcase type of projector there are certain variations slightly outside this class. Thus, there are machines of real compactness but somewhat heavier construction than the true portable type, and weighing in the neighborhood of 50 lbs. One of the offerings of this kind may be used for either films or lantern slides at will. All the mechanism is enclosed in an aluminum case. The lantern-slide projector is arranged on top of the motion-picture projector and makes use of the same lamp house, which is shifted upward into position when slides are to be used. Such a machine, and others of this general class, are still portable within the general meaning of that term, yet are sufficiently heavy in construction to give a somewhat better service than the lighter machines. Another offering is arranged with a case that holds the reels, and with the projector proper mounted on top of this case. The latter member can be .provided with four legs. Such a machine has greater possibilities, of course, than the suitcase type, yet still remains within the category of portable machines. The question of rewinding films is an important one for the non-theatrical projectionist, who is not apt to be provided with regular rewinding equipment such as is to be found in the theatre. In this respect it is well for us to pay some attention to the rewinding facilities afforded by some of the offerings. Provision for rewinding is to be found in certain portable projectors, either hy motor power or by hand. Still, this is only an added refinement, and after all it should not be a determining factor in the choice of any given machine. The DeVry Projector THE QUESTION OF NEGATIVES JUDGING from the inquiries that are being received of late from the numerous readers of this department it appears that there is considerable interest not only in the projection of films but in the making of films. That is to say, many readers of this journal are displaying an increasing interest in the camera end of motion-picture work. It is perhaps too early at this time to discuss the cameras and how they are employed ; but we are frank to say that we shall eventually touch upon that phase of motion-picture work at considerable length. For the time being, just a few words concerning the filming of motion-picture subjects. As in any other kind of photography, in motion-picture work we deal with a negative and a positive. The negative is made in the camera and is the master picture, so to speak, from which any number of positives or copies may be printed. The negative stock or film comes in rolls of 200 and 400 ft., as a general rule, carefully sealed in lightproof and moisture-proof tin boxes, because the film is highly sensitive to light, and moisture is apt to harm it. Negative film can be obtained in both the non-perforated and perforated state. The large motion-picture producers with extensive laboratories of their own generally prefer to do their own perforating, for the reason that they can save money by purchasing the film in the plain state and then doing their own perforating work, and this method insures perhaps greater accuracy; but for the little fellow it is certainly more advisable to buy the film already perforated. Negative film, perforated, costs 4 cents per foot, and for this reason it should be employed with a good deal of thought and care. It is too expensive to be wasted. Every scene should be studied and rehearsed before "shooting" the action, since wastage soon runs up into considerable money. Now when the film has been exposed in the camera, it must be developed. While the non-theatrical man may wish to do the developing himself, using the various kinds of equipment now on the market for this purpose, we are certainly not going to advocate this move very enthusiastically. Much depends on the proper development of the negative ; indeed, many an under-exposed or over-exposed film is salvaged by careful development, for the reason that the motionpicture negative emulsion has quite a latitude, and careful handling in the darkroom does much to save an otherwise hopeless negative. The amateur developing outfits are only recommended where one is far removed from any laboratory. In such cases they