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Authors

P. S. Helmick

Document Type

Research

Abstract

A photographic film was exposed to a measured quantity of monochromatic light-energy at 2536A, and the resulting number of silver bromide grains rendered developable by the exposure was determined by a direct microscopic count. It was thus possible to calculate the energy required to render developable a single grain of silver bromide. A mercury arc and an ultra-violet monochromator provided the monochromatic light-energy. Quantitative measurements of light-energy were made with a linear thermopile in combination with a Thomson galvanometer of figure of merit 4 X 10-10 amp/mm. One candle-meter on the thermopile gave a galvanometer deflection of 1500 mm. Preliminary results at this wave-length show that about 800 quanta are required to render a grain developable. Exposures made at other regions in the ultra-violet will be reported upon at a later date.

Publication Date

1923

Journal Title

Proceedings of the Iowa Academy of Science

Volume

30

Issue

1

First Page

75

Last Page

75

Copyright

©1923 Iowa Academy of Science, Inc.

Language

en

File Format

application/pdf

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