File:The American annual of photography (1922) (14595035639).jpg

Identifier: americanannualof36newy (find matches)
Title: The American annual of photography
Year: 1922 (1920s)
Authors:
Subjects: Photography
Publisher: New York : Tennant and Ward
Contributing Library: Harold B. Lee Library
Digitizing Sponsor: Brigham Young University

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publishedformulae almost every photographer has his own pet formulawith a reputation in many cases entirely undeserved, becausethe formula was not compared with the manufacturersformula under equally favorable conditions. These remarksapply also with regard to developing agents. Some photog-raphers use developing agents of unknown composition withsupposedly mysterious properties, although careful compara-tive tests would undoubtedly prove that the developing agentsin question are no better than the standard known developers. In this article it is the object of the author to explain howby simple tests the photographer may judge the merits of anydeveloping agent or developing formula with accuracy.Two methods of testing are possible: 1. The absolute method, by means of which the variousproperties of a developer are expressed numerically, and 2. The comparative method, whereby the developer to betested is compared side by side and under identical conditionswith a standard developer. 184
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A. J. Weis. The first method is obviously the ideal one, because if we canmeasure the properties of a substance and express them innumbers, then we really know something about that substance.Without the necessary apparatus, however, it is not possiblefor the photographer to express his various tests numerically,but by comparing a developer side by side with a standard, heis usually in a position to judge the merits of the developerwith sufficient accuracy for all practical purposes/ Classification of Developers. In photographic practice, the word developer is usedsynonymously with a developing agent—a complete developingsolution ready for use—and a developing formula, so that de-velopers may be classified as follows: 1. Developing agents. a. Composition known. b. Composition unknown. 2. Developers ready for use. a. Composition known. b. Composition unknown. 3. Developing formulae. i-a. In order to test a developing agent of known com-position, say hydroquinone, it should be compar

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