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vesicular film
Vesicular film, almost universally known as Kalvar, is a type of photographic film that is sensitive only to ultraviolet light and developed simply by heating the exposed film.
==History==
It was originally developed at Tulane University in 1956, and then commercialized by the Kalvar Corporation starting the next year. It was originally intended to make copying microfilm simpler, but also found a number of other uses. As the document processing world moved to computerized records, Kalvar was no longer in demand, and vesicular microfilm is now only made upon request.
Kalvar was intended to be used primarily for document storage, copying microfilm or microfiche. In this use the unexposed Kalvar was placed back-to-back with the original, and exposed to collimated UV light. The two films were then separated and the Kalvar run over a heated drum to develop and fix the image. The physical robustness of the Mylar base was an advantage, allowing it to be handled far longer than conventional silver-halide films of the era (early 1960s). The ease of copying also suggested its use in the distribution of movies, and in 1961 Kalvar and Metro-Goldwyn-Mayer formed a joint venture, "Metro Kalvar", to market a system for copying 16 mm and 35 mm black-and-white motion pictures.〔("The IPTE Exhibition: Metro Kalvar" ), ''The British Journal of Photography'', 26 November 1965〕 Both film sizes were commonly used for microfilm already, development was primary machinery related. Kalvar film was limited to reproduction of black and white only although a color process was developed. The color process used entirely too much light to be an economic success and never became commercially available.
Kalvar Corp was not the only company to commercially develop the process. In California, Xidex Corporation developed a similar process and filed a patent on it in the late 1950s. This eventually led to Xidex suing Kalvar for patent infringement, but when Kalvar demonstrated that they had been shipping commercial versions of their film in 1957, over a year before the Xidex filing, Xidex lost the suit.〔("Kalvar Corporation, Plaintiff-Appellant, v. Xidex Corporation, Defendant-Appellee" ), 556 F.2d 966 (9th Cir. 1977)〕 After losing, Xidex simply purchased Kalvar outright. This led to an antitrust suit being filed by the Federal Trade Commission in 1981, and Xidex agreed to sell off the entire Kalvar side of their business (they had several others) in 1983,〔David Barton and Roger Sherman, "The Price Profit Effects of Horizontal Merger, a case study", ''Journal of Industrial Economics'', Volume 33(2) (1984), pg. 165-177〕 which failed soon after.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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