Journal of the Society of Motion Picture Engineers (1930-1949)

Page scan 000278 from Journal of the Society of Motion Picture Engineers

Record Details:

Title:
Journal of the Society of Motion Picture Engineers
Date:
1930-1949
Publisher:
New York, N.Y. : The Society
Volume:
Journal of the Society of Motion Picture Engineers
Leaf #:
000278
Language:
English
Collection:
Technical Journals
Format:
Periodicals
Contributor:
Prelinger Library
Sponsor:
MSN
Coordinator:
Media History Digital Library
Description:
The Journal of the Society of Motion Picture Engineers (SMPE)Êdocuments the technological progress of the film industry, highlighting technical developments in production and exhibition. Of special interest are articles about special effects, theater practices, lighting, and the introduction of the 16mm format. Initially titled "Transactions of the Journal of the Society of Motion Picture Engineers."Digitized by the Prelinger Library and the Library of Congress Motion Picture, Broadcasting and Recorded Sound Division.
Date Added:
July 19, 2022
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1949 PHOTOGRAPHIC DEVELOPERS 275 These two absorbancies fix the point X on Fig. 2, which corresponds to an Elon concentration of 2.24 grams per liter and a hydroquinone concentration of 1.47 grams per liter. ANALYSIS OF USED DEVELOPERS Extraction of Elon and Hydroquinone with Ethyl Acetate Preliminary investigations showed that Elon and hydroquinone could be completely extracted from a developer solution at pR 8.0 to 8.5 by the use of a solvent such as ethyl acetate. Ethyl acetate was chosen because of its low toxicity, small fire hazard, and its relatively low absorbancy in the region of 270 to 290 millimicrons. Extraction of Oxidation Products Hydroquinone monosulfonate, quinhydrone, quinone, and Elon monosulfonate were selected as compounds that exist or would be converted into compounds that might exist in a used developer solution.12 A mix was prepared containing 3.88 grams per liter of sodium hydroquinone monosulfonate and no Elon or hydroquinone. The absorption curves were determined before and after extraction as shown in Fig. 3, curves A and B. Curve B has been adjusted to compensate for the dilution brought about by the pH. adjustment that was necessary to insure complete extraction. It is concluded from the curves A and B in Fig. 3 that the amount of hydroquinone monosulfonate extracted is negligible. The small difference between the curves may possibly be due to the presence of a small amount of hydroquinone in the sodium hydroquinone monosulfonate. In this study, this practice was followed for all curves obtained after extraction. 240 260 280 3OO 320 with and Wavelength mp Fig. 3 — Extraction study hydroquinone monosulfonate hydroquinone. A, hydroquinone monosulfonate. B, solution A after extraction. C, solution A with hydroquinone added. D, solution C after extraction.