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Some properties of fine-grain developers for motion picture film?
560
EASTMAN
I
NOTES.
[J. F. I.
SOME PROPERTIES OF FINE-GRAIN DEVELOPERS FOR MOTlON PICTURE FILM.3 H. C. Carlton and J. I. Crabtree. THIS paper describes experiments on (a) exhaustion tests, (b) methods of using the solution for machine development, (c) variation of the developer components to satisfy special requirements, and (d) methods of obtaining finer-grained negatives. (a) With the rack and tank system, the present published formula works satisfactorily until about eighty feet of panchromatic film per gallon have been processed. Revival with a solution containing half the original quantities of elon, hydroquinone, and borax permits an additional eighty feet per gallon to be developed when the solution should be discarded. (b) The rate of development may be increased by increasing the borax concentration up to twenty grams per liter. The development rate may be decreased and the graininess decreased slightly by lowering the concentration of developing agents and borax to one-half that present in the regular formula. This latter formula is very suitable for machine development. Hydrated sodium sulfate can be added to one hundred grams per liter to reduce further the rate of development and the graininess. (c) The rate of development can be controlled for special requirements by using eight grams of boric acid and eight grams of borax per liter in the usual formula. By varying these quantities but also keeping the total constant, the development rate can be increased or decreased as desired. High concentration of boric acid gives a solution which becomes exhausted more rapidly. (d) Graininess of images can be improved in three ways: (I) by increasing the sulfite to give increased solvent action (recommended only when the developer can be discarded at frequent intervals) ; (2) by decreasing the rate of development by using a solution containing less alkali and reducing agents ; 3 Communication No. 388 from the Kodak Research Laboratories and published in Amer. Cinemat. IO: 17, 1929, and read before the Society of Motion Picture Engineers, New York City, May, 1929.
Oct., 1929.l
EASTMAN
KODAK
COM~A~'Y
KOTES.
561
(3) by development of the negative to a relatively low gamma and the positive to a relatively high gamma. The developer can be used for development of positive film but other than reducing the propensity of the solution to aerial fog, it possesses no advantages for this purpose over other developers.
EASTMAN
I
NOTES.
[J. F. I.
SOME PROPERTIES OF FINE-GRAIN DEVELOPERS FOR MOTlON PICTURE FILM.3 H. C. Carlton and J. I. Crabtree. THIS paper describes experiments on (a) exhaustion tests, (b) methods of using the solution for machine development, (c) variation of the developer components to satisfy special requirements, and (d) methods of obtaining finer-grained negatives. (a) With the rack and tank system, the present published formula works satisfactorily until about eighty feet of panchromatic film per gallon have been processed. Revival with a solution containing half the original quantities of elon, hydroquinone, and borax permits an additional eighty feet per gallon to be developed when the solution should be discarded. (b) The rate of development may be increased by increasing the borax concentration up to twenty grams per liter. The development rate may be decreased and the graininess decreased slightly by lowering the concentration of developing agents and borax to one-half that present in the regular formula. This latter formula is very suitable for machine development. Hydrated sodium sulfate can be added to one hundred grams per liter to reduce further the rate of development and the graininess. (c) The rate of development can be controlled for special requirements by using eight grams of boric acid and eight grams of borax per liter in the usual formula. By varying these quantities but also keeping the total constant, the development rate can be increased or decreased as desired. High concentration of boric acid gives a solution which becomes exhausted more rapidly. (d) Graininess of images can be improved in three ways: (I) by increasing the sulfite to give increased solvent action (recommended only when the developer can be discarded at frequent intervals) ; (2) by decreasing the rate of development by using a solution containing less alkali and reducing agents ; 3 Communication No. 388 from the Kodak Research Laboratories and published in Amer. Cinemat. IO: 17, 1929, and read before the Society of Motion Picture Engineers, New York City, May, 1929.
Oct., 1929.l
EASTMAN
KODAK
COM~A~'Y
KOTES.
561
(3) by development of the negative to a relatively low gamma and the positive to a relatively high gamma. The developer can be used for development of positive film but other than reducing the propensity of the solution to aerial fog, it possesses no advantages for this purpose over other developers.