International projectionist (Jan 1941-Dec 1942)

■ FIG. EIGHT why they rotate in the same direction. Shutter 0, in Fig. 6, is intercepting light which was originally the top of the beam. If shutter 0 were placed beside shutter L instead of at the opposite end of the lens, 0 and L would have to rotate in opposite directions, which would involve more gearing and much greater complications in securing proper alignment and trim. There would also be a chance of the two shutters getting out of adjustment with respect to each other. Mounted as they are, however, at opposite ends of the lens, the front and rear shutters are very simply adjusted [the light-cutting edges being brought exactly in line with each other] ; they rotate in the same direction [there are no gears at all between them, they being mounted on the same shaft], and since they are solidly mounted to their common shaft, they must maintain their proper relationship. The Lubrication System Figure 7 outlines the general principles of the lubrication system of the Simplex E-7 projector, in which P is an oil reservoir, Q a pump lever, and T a distribution Dlock. The pressure gauge shown in the model is not used on the projector, being added in this case for demonstration purposes. The lubricant, having been put under pressure by pushing lever >Q down two or three times, flows, under pressure, to filter R, whence it enters shaft S and emerges between the shaft and the gear through the hole seen in the middle of the shaft. There, still under pressure, it is forced by the lubricant following it to wash away toward the PATRONS WILL PAY NEW TAX AT B. O. AFTER OCT 1 The public will carry the load of the new admission tax regulations which went into effect Oct. 1. Major circuits, independent circuits and individual theatre operators indicated that no attempt would be made to absorb the tax. In brief, the tax law applies to all admissions starting with the first penny, except tickets selling for less than 10 cents to children under 12 years of age. It is reported that Loew's and RKO are contemplating a policy of "even" admissions in order to eliminate the odd pennies. Where the price now is 28 cents with tax, the price would be put up to a 30cent level if the plan is adopted. This policy has been in effect in 85 per cent of the Skouras theatres for some time, and will be extended to the entire circuit shortly. two ends of shaft 5. The shaft is in this way supplied with a continuously replaced film of fresh, filtered lubricant, which additionally exercises a washing action, flushing away and out at either end any dirt or metallic particles. In the actual projector, of course, a number of oil lines leave the distribution block in parallel, conveying lubricant to many bearings and shafts. The necessary pressure is maintained by manipulating lever Q two or three times in a long working day. The reservoir is refilled at long intervals through the oil cap seen just in front of the lever. The sight gauge tells when refilling is necessary. A second and vital part of the system is shown greatly enlarged in Fig. 8, which is simply section R of Fig. 7 cut away to show internal construction. Lubricant enters Fig. 8 at the right and flows past shaft V after its pressure has overcome the resistance of spring W . The action of the spring, which opposes the pres sure of the lubricant, lends assurance that oil flowing through Fig. 8 will flow at the pre-determined pressure. It flows past pin V, which fits very closely in the hole drilled through material X — X. Both the diameter of this hole and the diameter of pin V are accurately machined: the clearance is pre-determined and the amount of oil passing per minute is thus also pre-determined. Each bearing or shaft to be lubricated is fitted with one of these devices [/? of Fig. 7] in which the diameter of pin V has been chosen to admit the correct amount of lubricant for that location. U in Fig. 8 is a double filter consisting of metal mesh, seen in the photograph, and of a felt filter inside the mesh, which cannot be seen. This filter does not clog because the flow of lubricant is toward the filter — from right to left in this photograph— and any dirt which may have gotten past the filter in P of Fig. 7 does not enter the filter of Fig. 8 but drops away at the surface of U. New RCA Lens-Coating Process Available ANEW technique for improving the efficiency of motion picture projector lenses by coating the glass surfaces with a durable transparent film that produces clearer, more contrasting pictures on the screen without the necessity of otherwise adjusting the projector, has been developed for commercial uses by RCA. The process, known as RCA Magicote, is also being employed in Hollywood to increase the efficiency of camera lenses. Finer detail, sharper contrast, and improved color values, all result from the application of this development. The principle of lens coating is not an entirely new, discovery, states the RCA announcement. Scientists have long understood that when a beam of light strikes a pane of glass, not all the light passes all the way through. An average of approximately 4% is reflected at the first glass-air surface, so that only about 96% passes on through to the second. Then another 4% is turned back at the second glass-air surface, so that only about 92% of the light actually passes all the way through and out from the other side. If additional panes of glass are inserted in the light path, each one contributes reflections that similarly turn back and scatter some of the light rays. High Light-Transmission Loss In the case of lenses with a multiplicity of elements, such as those employed by projectors and cameras, the reduction in and scattering of the light passing through the lens noticeably impairs the brightness and quality of the projected image. For instance, with a lens having eight glass-air surfaces, the light loss amounts to 30% or more. RCA further points out that although some of the light rays reflected by any glass-air surface of a motion picture projector lens eventually reach the screen through being reflected back toward the screen by the other surfaces they encounter, they arrive as diffuse light rather than as directed rays which shape up and outline picture details. Thus they tend to wash out a picture in a manner similar to that when diffuse extraneous light is allowed to play upon the screen. In the case of colored pictures, this misdirection and scattering of light rays is particularly harmful, as it tends to mix the colors. A theatre, if it wished, could also offset the light lost by uncoated lenses by boosting the arc power, but that this means added daily operating costs, furthermore, this would do nothing toward offseting the harm done by the scattered diffuse light. Only a scientifically-applied coating strikes at both problems and gives improved picture quality along with a more brilliantly lighted picture. The coating applied to the lens surfaces by the RCA Magicote processes practically eliminates reflections. Its thickness is carefully controlled to be one-quarter the wavelength of visible light or about five millionths of an inch. RCA developed a coating which exhaustive tests show is very durable and at the same time very efficient. RCA's field force will handle the new lens-coating activity. Lenses are shipped to the RCA plant at Indianapolis, where ample facilities for applying the Magicote surface have been installed in a special air-conditioned laboratory. Application of the coating requires less than three days. 14 INTERNATIONAL PROJECTIONIST