Transactions of the Society of Motion Picture Engineers (1929)

Record Details:

Title:
Transactions of the Society of Motion Picture Engineers
Date:
1929
Publisher:
New York : Society of Motion Picture Engineers
Volume:
Transactions of the Society of Motion Picture Engineers (1929)
Leaf #:
000386
Language:
English
Subjects:
motion pictures, Cinematography -- Periodicals
Collection:
Technical Journals
Format:
Periodicals
Contributor:
Library of Congress, MBRS, Moving Image Section
Sponsor:
Library of Congress, Motion Picture, Broadcasting and Recorded Sound Division
Coordinator:
Media History Digital Library
Description:
Preceeded by an unnumbered issue published in 1916 called: Incorporation and by-laws
Date Added:
November 17, 2022
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370 Transactions of S.M.P.E., Vol. XIII, No. 38, 1929 i. Hardening. The relative hardening produced by a given fixing bath was determined as the temperature at which the emulsion left the support after treatment in the following standard manner : Strips of Eastman motion picture positive film % inch by 5 inches were exposed so as to produce three densities at one end of the strip, ranging from approximately 0.5 to 2.5 after development. These strips were developed in MQ25 diluted 1 :1 for 2 minutes, rinsed 30 seconds, fixed 5 minutes in the fixing bath to be tested, and washed 15 minutes in running water. The temperature of the solutions up to this point was maintained between the limits of 65° to 70° F. The film was then placed on a wooden frame which was immersed in a beaker containing 750 c.c. of water at 70° F. The temperature of the water in the beaker was raised from 8° to 10° F. per minute and the temperature at which the gelatin emulsion left the support was taken as the melting point or a relative measure of the hardening produced by the fixing bath. The apparatus as used is illustrated in Fig. 1. The temperature at w^hich the gelatin FiGiTRE 1. Apparatus for determining the melting point of the gelatin coating on motion picture film. emulsion reticulated was not recorded after the first few experiments because it was found that this value is related to the melting point by a definite ratio. The degree of hardening produced depends on a large number of factors all of which must be maintained constant if consistent results are to be obtained. Some of these factors may be tabulated as follows: