Moving Picture Age (Jan-Dec 1922)

MECHANICS of VISUALIZATION A Department Conducted, by AUSTIN C. LESCARBOURA, SSiSelan In this department appear each month discussions of the important materials of visual instruction — projectors, films, stereopticons, slides, screens, cameras, lenses, and other items of equipment on which the non-theatrical exhibitor should possess authoritative and impartial information. It should be distinctly understood that all expressions of opinion emanate from Mr. Lescarboura, and that Moving Picture Age takes no stand upon the opinions expressed in this department. THE SEMI-PROFESSIONAL PROJECTOR 7 What problems are handicapping you in your visual in* struct ion work? Mr. Lescarboura stands ready to answer by correspondence the questions of any subscriber pertaining to equipment, when the inquiry is addressed to him at the office of Moving Picture -^ Age and is accom •■ panied by stamped, f addressed envelope # — The Editor. Acme Semi-Professional Projector THE DEMAND for something between the large and somewhat complicated machine of the theatre and the light and necessarily limited-capacity projector of the portable variety, has given rise to the semi-professional category. Indeed, this category or class of machine fills a long-felt want in nontheatrical motion-picture work, for it is sufficiently powerful and rugged to withstand the service called for in the large auditorium where regular programs demand real and constant service, and it is sufficiently simple and small to be operated by anyone with the minimum of expense. Please note that the semi-professional projector does not take the place of the portable type, nor does the portable type, in turn, do the work of the semi-professional type. There is much misunderstanding regarding the relative functions of these two types, which appear to be so closely allied. Yet as a matter of fact they are intended for quite different purposes. The portable is especially desirable where portability is prerequisite, and there are enough applications of this kind now that motion pictures are so widely employed in other than theatrical ways. For class-to-class use in the school the portable or suitcase machine has a very definite field of service. Again, for use in very small halls, seating several hundred people, the portable machine is also available, -for it throws a fairly large picture of good brilliancy. But when it comes to the large auditorium and the steady grind of evening after evening or day after day of pictures, the semi-professional projector is certainly the better choice. It is built to stand more grueling service, and is simpler to thread and operate because of the accessibility of its exposed parts. The semi-professional machine is a cross between the portable and the professional machines, and as such it has some characteristics of both types. As a matter of truth, however.it partakes more of the professional machine, and at a glance it resembles the latter to a striking degree, even if the construction is ndticeably lighter. First of all, the semi-professional machine has an incandescent lamp for the illuminant, just as the professional machines now intended for non-theatrical work are also being provided with incandescent lamps instead of arcs, which are troublesome to operate and require the services of a skilled operator. The relatively low current consumption of the semi-professional machine enables it to be connected to the usual lamp socket or outlet, as compared with the professional machine, which must have special wiring even if it employs the incandescent lamp instead of the arc. Of course the semi-professional machine has motor drive ; in fact, all offerings, aside from mere toys, have motor drive. The motor is generally so neatly mounted that it forms an integral part of the machine. A speed controller permits of varying the projection speed. The problem of rewinding is taken care of in most of the semi-professional offerings. The film is rewound right in the machine itself, either by using a special crank which is placed on the empty reel, or by reversing the motor drive in such a manner that the rewinding is done by motor without effort of any kind. At any rate, this matter of rewinding in the machine itself is a commendable practice, because, as has been explained in these columns before, Zenith Semi-professional Projector 15 the less exposed the film is the better for all concerned. It is not in the projector that most serious film fires take place, but during rewinding and when the reels of film are left lying about, inviting the spark from a cigarette or from some electrical flash. It is well, too, for the prospective projectionist to look into the matter of stereopticon attachment. If there is any possibility of using lantern slides at some time or other, then by all means a projector with a stereopticon attachment should be selected. Most of the offerings have stereopticon attachments that make use of the same lamp house but different optical systems, the lamp house being shifted up and down or sideways, in order to align it with either the motion-picture projecting system or the stereopticon system. Semi-professional projectors are distinguished at a glance from the portable types of projector in that the former are provided with their own stands. Most of the offerings have telescopic legs that hold the projector in place, and which can be adjusted so as to obtain any desired height and any angle. This neat arrangement makes it possible to instal the machine in a small fireproof booth with a minimum of bother. The methanism of the usual semi-professional machine is simple and easy to get at. The various parts can be readily taken down, inspected, cleaned, and adjusted or repaired if necessary. This simplicity and ready upkeep has much to do with making this type a great favorite in all kinds of non-theatrical work, where the services of a professional or skilled operator are out of the question. Somewhat different from the strictly semi-professional type are various offerings that nevertheless belong in that general classification. We have reference to machines which may resemble the portable type in that they have no stand of their own and are somewhat more compact than the semi-professional type, yet are so rugged and readily attended to that they are true semi-professional projectors. One of these machines that is attracting considerable attention and is apparently favored by many is a compact machine contained almost entirely in a case of cast aluminum. The film is placed in fire-proof magazines, which in turn are contained in the cast aluminum case, making fire danger practically nil. The motor drive, motionpicture optical system, film reels, and electric resistances are all included inside the case. However, the lamp house is outside the case and is so mounted that it can be slid down in order to project motion pictures, or slid up and aligned with the stereoptical attachment mounted on top of the case when required. This type of projector, which has virtually all the features of the semi-professional machine except that its parts are not quite so accessible, can be placed on a desk or table anywhere and connected with the nearest lamp socket. Another type of machine also sets on any desk or table. It has a rather peculiar mechanism that is certainly different from any on the market. The lamp house throws a beam parallel to the surface of the screen, but this beam, after passing through the film, is bent at right angles by means of a prism and then projected on the screen. The film is contained in the base, and such film as passes up through slots in the base is contained in glass-cased sections where it can be seen but is in no way exposed. A num