Abstract
The chief sources of error in the photographic method of comparing light intensities of the same wave-length are the variations in density over the plate caused by its irregular structure and its uneven development. The causes and magnitudes of these errors are studied by exposing plates to a field of illumination the degree of whose uniformity of intensity is measured with a photo-cell and amplifier. The main objections and difficulties ordinarily associated with the photographic method are briefly discussed, and methods are suggested for their control and correction.
© 1934 Optical Society of America
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