An Intensity Scale Sensitometer for testing the photographic response of Graphic Arts materials was built and evaluated. The sensitometer utilizes a stepped area diaphragm and a cylindrical lens to produce a stepped illuminance distribution at the film plane. Both tungsten and pulsed xenon lamps are provided. A computer aided study was used to find the optimum lamp position with respect to the reflector. A scanning aperture type shutter located at the stepped diaphragm and a knife edge aperture located at the lens are used to control exposure duration and intensity. The main advantage of this sensitometer is the production of an intensity scale without interposing a light absorbing step wedge. This permits graphic arts screens to be overlayed directly on the film simulating practical exposures. The unique ability of this sensitometer to provide complete "system" photographic response (density - vs – log exposure or percent dot - vs - log exposure) was demonstrated through the use of practical exposures. The spectral distribution at the exposure plane and absolute Irradiance at each exposure step were measured. Exposure uniformity is estimated to be better than 2% for tungsten and 4% for pulsed xenon.

Library of Congress Subject Headings

Photographic sensitometry

Publication Date


Document Type


Department, Program, or Center

School of Photographic Arts and Sciences (CIAS)


Schumann, G. W.


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