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Why Slide Film?— Rogers 231
2. What are the advantages of slide film?
During the three years just passed the use of sHde film has grown from nothing to proportions deserving attention. The idea has received a favorable acceptance. The use is still limited when compared to the possibilities of use in the field.
What are the advantages? I shall list each in order, then follow with a brief comment.
A. Low Cost;
B. Satisfactory Projection;
C. Ease and Simplicity of Operation ;
D. Lightness, Compactness and Portability of Projector and Film;
E. Freedom from Breakage of the Film. Durability.
A. Cost. The low cost of slide film prints has been an important factor for success. After a negative is made, slide film prints can be made almost as cheaply as regular motion picture positives. Assume that the average slide film is about 80 frames long or roughly 5 feet. In general, the customers price for this specially made strip will range from 14.00 for single orders to $2.00 in quantities of twenty or more ordered at one time. The selling price of prints from a film library where the negative cost has been amortized range from 50c to $3.00. In other words the customer receives a set of 80 frames, the equivalent of a set of 80 lantern slides for $2.00. An average price on lantern slides is 50c a piece. Eighty slides ordinarily would cost about $40.00.
B. Illumination. For many uses, and probably most, the screen illumination is adequate. This is especially true where the throw is short or at distances from 10 to 40 or 50 feet. A satisfactory picture may be projected in a darkened or partially lighted room.
C. Simplicity. Neither technical knowledge nor a high degree of skill is necessary to operate slide film projectors. Most operate either by pressing down a lever with the thumb or turning a round handle or button. This causes the picture next in order to appear. Some of the machines may be turned backward one or more frames to repeat the showing of a scene where desirable. Usually the film is wound on a reel about the size of a large size spool or in some instances wound on itself without the use of a reel. The free end after being fed through the aperture is rewound on a take-up spool or runs free. The operator rewinds by hand around his finger.