This invention relates to photographic film cassettes and, more particularly, it concerns a novel large capacity film cassette for use with projection apparatus having film drive and projection components disposed within a receiving well establishing an essentially enclosed space smaller than the space occupied by the film strip coiled within the novel cassette.
U.S. Pat. Nos. 3,778,140 and 3,800,306 issued respectively on Dec. 11, 1973 and Mar. 26, 1974 to Edwin H. Land contain exemplary disclosures of a motion picture system by which a supply of light-sensitive film contained in a multi-purpose cassette can be exposed in a camera adapted to receive the cassette and then processed or developed to provide the conventional series of positive transparent image frames by placing the cassette in a projection apparatus or viewer capable of activating a processor also contained in the cassette. In such systems, once the film strip has been exposed, the image sequence recorded thereon may be viewed by projection after a time interval only as long as that required to rewind the film strip and during which the processing operation is performed. Also, repeated projection cycles may be carried out subsequent to processing a film strip in a given cassette merely by replacing that cassette to the receiving well of the viewer which is equipped with an automated control system capable of detecting the processed or unprocessed condition of the cassette. Where the multi-purpose cassette had been previously processed, the control system operates the projection apparatus through a projection cycle, followed by a film strip rewind cycle and ejection of the cassette from the well.
The multi-purpose film cassette by which the film processing operation is effected in such systems most appropriately functions as an essentially permanent receptacle for the film strip contained therein beginning with packaging of the unexposed light-sensitive film strip, throughout exposure and processing and as a permanent storage and handling receptacle for the film strip after processing for repeated projection cycles if desired. One of the major advantages of the multi-purpose cassette, therefore, apart from the facility it offers for instant processing, is that it obviates any need for physical handling or direct manipulation of the film strip itself. On the other hand, capacity of such a multi-purpose film cassette or the length of the film strip it will accommodate is a compromise of such factors as the length of film strip to be sold in one package, the desirable length of film strip to be exposed without removal from the camera and the length of developed film strip to be viewed or projected at one time. Obviously, the ideal length for projection is much greater than that for packaging or for exposure particularly for amateur photographers.
In addition, the projection apparatus or viewer of such systems represents perhaps the largest single investment required of one to use the overall system. Although the viewer is particularly adapted to handle multi-purpose film cassettes of the type containing a supply of processing fluid for the development of film contained in the cassette after exposure, it provides a highly sophisticated projection apparatus adaptable for use also with films supplied, exposed and developed by conventional means as well as with films of longer and thus more desirable projection lengths than those available in the multi-purpose cassette designed expressly for the system. It should also be realized, however, that since the projector is designed for a cassette of specific capacity having given spool inertia, etc., some accommodation must be provided where a cassette of large capacity is employed.