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1945 Theatre Catalog, 4th Edition, Page 332 (308)

1945 Theatre Catalog, 4th Edition
1945 Theatre Catalog
1945 Theatre Catalog, 4th Edition, Page 332
Page 332

1945 Theatre Catalog, 4th Edition, Page 332

likely to be scratched by dirt if there is any. The construction of the Simplex E-7 makes it extremely easy for the projectionist to keep this region immaculately clean. He can without dif'liculty and very quickly remove trap and gate both in order to clean them completely; and he could do it between reels without taking any appreciable amount of time from his other between-reel duties.

The white-enameled illuminated interior of the operating side of the mechanism is another provision against dirt. Dirt could hide and accumulate far more easily in a dark and obscurer lighted film compartment.

Sharpness of Focus

Maintaining sharpness of focus on the screen is largely a matter of keeping the film fiat at the point where it is being projected. If the film is corrugated (buckled), or if the little still picture under-going projection swells out like a sail in the wind, every part of the film image will not be at the same distance from the lens. Then it will be an optical impossibility to secure a screen image in sharp focus at every point. Under such circumstances some areas of the picture that the audience sees will be

blurred, often very badly blurred.

At the instant when a given film image comes before the aperture to be projected, it comes into a region of higher temperature, and therefore expands. Since the film is very rigidly held in the aperture (to insure that the picture on the screen will be steady) the only way the film image can expand is by swelling like a sail. This is called fibreathing" of the film. It impairs the accuracy of the focus. It must therefore be kept to a minimum.

Sometimes, especially with high-intensity sources, the heat at the aperture may become great enough so that the film is partly dehydrated, and wrinkles or fibucklesii in consequence. This is a permanent injury, not a temporary condition like breathing. When that print is run next show, it will give a blurred image, and nothing can be done about it. It will never give a sharp picture again.

Buckling must be prevented and breathing minimized. For these purposes the Simplex E-7 is equipped with a highly efficient cooling system. Cooling air, however, is not blown into the film compartment-it might carry dirt or carbon particles with it to soil or scratch the


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film. Instead, a sight box, through which the light must pass, is cooled, and thus a great deal of heat is taken out of the light beam before it reaches the projector. This ribbed sight box, located between aperture and rear shutter, intercepts and disperses heat so efficiently that at the end of a full days operation it is not even warm to touch. The sight box in turn, is cooled by powerful vanes mounted on the rear shutter, which act like a strong suction fan, drawing air backward from the aperture.

The physical design of the mechanism, further, minimizes the effect of buckling. The film does not run free between gate and intermittent, but is firmly held in position by the intermittent film guide at the point where it leaves the gate. The result is that faults in focus caused by breathing of the film, and any possibility that the next show and future shows will be marred by buckling, are substantially eliminated.

Micrometer-type lens adjustment also assists materially in securing and maintaining the utmost sharpness of focus on the screen.


Space does not permit describing the many other devices and mechanical features incorporated into the Simplex E-7 mechanism for the purpose of giving ideal screen results, nor the sometimes elaborate considerations that govern the exact choice of materials to be used at every point. In each small detail the designers, guided by an immense background that reaches back to the earliest pioneer days, have sought to find the uone best way" and to build the projector accordingly.

Eight years of experience in the thousands of theatres in which Simplex E-Ts are installed, and the many laudatory comments from exhibitors, projection supervisors, and projectionists using the mechanism, ofi'er flatterineg impressive evidence that those efforts have been highly successfulethat the E-7 is in fact what its designers tried to make it: the world's finest projector, build for tomorrow today.


Motiograph projector equipment is available as follows: Model K deluxe mechanisms, Model S stands, Model K 18-inch upper magazines, and Model K 18sinch lower magazines.

Model K de luxe Mechanisms

A few of the features of the Model K deluxe projector mechanism are cast iron case and main frame on a main frame casting designed for strength and rigidity, with removable oilvabsorbent bushings permitting easy replacement of standard-size shafts.

The one-piece horizontal cylindrical shutter rotor is statically and dynamically balanced, free running on large ball bearings, permanently adjusted for end play. This rotor gives more light on the screen than any other shutter mechanism and a fiickerless dissolving effect found in no other type shutter.

The rotor of the automatic air cooling systems draws temperature air through housing, forcing it toward film gate door,

1945 Theatre Catalog, 4th Edition, Page 332