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Refrigerant Cleans Photographic Film.--The same type of chemical that freezes ice in a refrigerating system and serves as the cooling agent in air conditioning is now proving itself as a better, faster photographic film cleaner.
It's Du Pont "Freon-ll3" fluorinated hydrocarbon, a nonflammable liquid that eliminates the bothersome, sometimes dangerous, odors of other solvent cleaners. Tests reported by the Motion Picture Research Council, Inc., show "Freon-113" to be "much less toxic, better in some cleaning operations, and equivalent in all other operations tested" in motion picture studio work Because it's fast-drying, "Freon-113" speeds up film cleaning--as much as 10 to 20 per cent in machine operations. Adaptable to both machine and hand use, it effectively dissolves and washes away gums and oils that "dirty up" photographic film, but does not affect the emulsion of either black and white or color film.
Color motion picture film positives have been cleaned repeatedly with "Freon-113" with no measurable deterioration of color intensity. In the past, effective life of many types of color film has been limited by color fading and running when they were cleaned with other, less selective, solvents.
The versatile chemical, currently available only in 100-and 200-lb. drums, also can be combined with beeswax or cetyl alcohol to make a lubricant for treatment of motion picture film before projection.
A solution of 0.1 per cent of beeswax or cetyl alcohol in "Freon-ll3" fluorinated hydrocarbon makes a good lubricant. If a higher wax concentration is desired, a co-solvent such as cyclohexane may be added in the ratio of 6.7 per cent cyclohexane to 93.3 per cent "Freon-ll3" by weight. This combination will dissolve 0.2 per cent of its weight of beeswax. Some laboratories have found that the addition of a small amount of wax to their "Freon-ll3" cleaning solution permits cleaning and lubrication of film in one operation.
Although of very low toxicity, "Freon-ll3" should be used only in wellventilated work rooms, especially in hand cleaning where the local vapor concentration may be high. Like most solvents, it has a "drying out" effect on the hands, and rubber or neoprene gloves should be worn when the chemical is being used over any extended period.
๐ SIMILAR VOLUMES
THE observation of Professor Cheshire and Doctor Curtis that photographic film is subject to a large and, moreover, irregular contraction during the process of development, etc., is confirmed only in the case of non-curling film. For motion picture, aerial, portrait, and process films, the contracti