Projection engineering (Sept 1929-Nov 1930)

Page 22 Projection Engineering, April, 1930 Effect Lighting in Theatres Original Account of Present-Day Methods of Producing Various Realistic Effects on Theatre Screens (Concluded from March issue of Projection Engineering.) The Standard Double Effect THE peculiar nature of the motion picture program — peculiar, that is, only in that it differs greatly from the heretofore accepted form of popular entertainment — revealed the need for a projection device especially adapted to producing those lighting effects which seem to find ever-increasing favor among theatre patrons. It was only natural, therefore, that such a device should find a place in projection rooms. This is the now accepted standard double effect projector which first made its appearance some five or six years ago. The advantages it holds over the spotlamp type of effect projector are as listed below : 1. Higher operating efficiency. 2. Produced effects which can be obtained by no other means. 3. Projects dissolving lantern slides. 4. Greater flexibility in operating. 5. Requires but one attendant for multiple effects. 6. Easy to operate. Aside from these, there are certain advantages which result from its placement in the projection room since in its location it comes under the supervision of the projectionist who is, or at least should be, more skilled in handling such projection devices, than are other employees about the theatre. Furthermore, the centralization of such projection devices in the main projection room places the responsibility for their successful operation in one person's hands instead of distributing it among various persons about the theatre. This naturally assists the systematic departmentization of the theatre so necessary to efficient operation. In its simplest form, the double effect projector is nothing more than a dissolved stereoptican to which have been added horizontal and vertical framing shutters, iris shutters, dowser shutters, a hinged slide carrier for swinging out of the way, effect holders, mask holders, extra projection lenses, a means for quickly altering (vertically) the direction of both light beams, and a means for quickly tilting or swiveling the entire projection mechanism so as to cover any desired portion of the "front of the house." For projecting lantern slides, it is operated in the ordinary fashion like any other slide projector. It can also be used in an emergency, By James R. Cameron although lacking in intensity, to project "spots" or floods of special odd shapes by the simple expedient of placing a suitable cut-out in the slide carrier, or by manipulating the iris shutter. As an effect projector, it can produce either single or double effects by placing a revolving disc effect unit in one, or both, of the holders attached in front of the condenser lenses. Blending or dissolving colors, projected to any portion of the front of the house, are obtained by placing a suitable color wheel in the front effect holder. Glass design slides, cut-outs, or ordinary lantern slides are placed in the standard slide carriers located in the usual position before the condenser lenses. The framing shutters, iris shutters, and special mask holders, are attached, in complete assembly, to the front of the lamphouse in such a manner as to be between the condensing lenses and the standard slide-carrier. Control over the area covered by the effect — whether projected on the motion-picture screen or over the entire stage opening — is obtained by means of two projection lenses in each system. These lenses, one of which is of short focal length and the other of long focal length, are mounted at opposite ends of a lens barrel and are pivoted to permit each being quickly swung out of the way so that a rapid selection of lenses is possible. The short focal length lens is for projecting effects over the entire stage opening any desired reductions in size being obtained by means of the various shutters provided, or by using a special mask. The long focal length lens (nearest the screen) is more commonly referred to as the stereoptican lens since it is chosen with a view to projecting a picture of the same size as that formed by the motion picture projector. The picture size can be varied, of course, by substituting lenses of any required focal length, which operation requires but several minutes. This projector is equipped with either arc lamps or light wattage projection type incandescent lamps whichever may be desired. The latter are satisfactory on projection distances up to about 100 ft. Triple Effect Projectors In the same manner that a spotlamp is limited to the showing of single effects so, also, is the double effect projector limited to the simultaneous projection of two effects. There are occasions where the restrictions of the double machine are keenly felt, as for instance, where it is desired to show dissolving slides along with a general animated effect. Then, too, there are certain effects, such as a volcanic eruption where nothing but a triple-optic system device can be used. Such occasions, to be sure, are not as numerous as where double effects are desired; nevertheless there are times where the lack of these facilities is a drawback. High Intensity Arc Single Effect Projector The constantly increased size of new motion-picture theatres is makingstrenuous demands upon all types of projection equipment ; not alone as regards spotlamps and effect projectors, but also upon motion-picture projectors. A brighter source of light, the high intensity arc, has for some time past, been used for motionpicture projection, but it was only recently that the same source was applied to the projection of lighting effects. Being an entirely new piece of projection apparatus, the potentialities of this high intensity effect projector have not, as yet, been fully uncovered and its principal use, therefore, has been confined to producing colored floods, spots and odd-shaped illuminated designs. In addition to being able to project single animated effects, color effects, and cut-outs, slides and the like, it appears to have unlimited possibilities in the way of special effects of a type heretofore impossible of attainment due to the limitation of intensity of illumination available for such purposes. Its reception by theatres during the brief time in which it has been available has been, without exception, most favorable so that it seems quite likely that it will find a place in the projection rooms of all de luxe houses. Briefly, by way of description, it consists of essentially the same elements as found on the standard double effect projector in that the necessary framing shutters, iris shutter, special mask holders, and adjustable slidecarriers are mounted, in one assembly, before the condensers of a standard high intensity lamphouse. Three (or as many as may be desired) projection lenses of graded focal length are used, these lenses