File:The American annual of photography (1922) (14801576363).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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e, which is very sensitive to bromide, shadow detail inthe negative is lost. Pyro, Elon, and Ortol are less sensitiveto bromide and should therefore predominate in a negativedeveloper. Pyro oxidizes rapidly and gives stain unless anexcess of sulphite is added, which in turn tends to producefog. For motion picture positive work the effect of the ac-cumulated potassium bromide is of less importance, since thiscan be cornpensated for by increasing the printing exposure. In tank work, as the developer becomes exhausted as a resultof performing useful work, it is customary to increase the timeof development by about one minute per day so as to main-tain a coiiJtant contrast of the negatives. Tank developers should be given a thorough exhaustion testby developing camera exposed or flashed films in a deep glasstank containing about half a gallon of solution, a sufficientnumber of films being developed daily so as to correspond toan average daily run in a fifty or one hundred gallon tank. 212
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STUDY. JANE REECE. 213 Graded strip tests should also be made daily and developed toa given density contrast, the density of the lowest steps whichare a measure of the detail giving power being carefully noted,(c). The alkalinity should not be excessive; otherwise, theacid fixing bath soon becomes neutral as a result of the neu-tralization of the acid by the alkali in the developer carriedover by the films. The following example illustrates the method of testing tankdeveloper.Report on a Deep Tank Developer Formula for Amateur Finishers.The formula submitted was tested against the standardformula by first developing flashed sheets of NC film for 15minutes at 70° F, the tests being repeated after allowing thedevelopers to stand in open trays over night and diluting tothe original volume to compensate for evaporation. The re-sults were as follows: 1st Day Density Test Formula. ... 1.50 Standard Formula 1.06 This preliminary test showed that the developer submitted has excellent keeping

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