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The NCR Archive: Nitrate and Safety Negatives  he familiar plastic-based photographic negatives and slides we all know and use are a relatively recent development. Eastman Kodak pioneered the first practical use of cellulose nitrate film sheets in 1903. The negatives incorporated a thick nitrate film base and a gelatin coating on both sides. Nitrate based negatives were used by NCR in 1916, in conjunction with glass plate negatives. By 1920 the use of nitrate negatives became the norm, although glass negatives were used for some special applications as late as the 1970s. By 1937, NCR had begun using cellulose diacetate negatives. The gradual replacement of diacetate with cellulose triacetate base negatives began in 1947. It is estimated that the NCR Archive contains well over one million nitrate and safety negatives (both diacetate and triacetate). Unfortunately, nitrate film is inherently unstable, becoming acidic, sticky and brittle with age. Diacetate negatives suffer from shrinkage of the film base, discoloration and progressive embrittlement. In order to slow down this process, MCHS has begun refrigerating what it considers the most important images from this time period. Over 10,000 negatives have been rehoused and are now being stored at a temperature of about 42 degrees fahrenheit. Studies indicate that, at this temperature, there should not be any appreciable changes in the negatives for the next 1,000 years. BACK TO TOP |
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