Abstract

The problem of obtaining accurate photometric data at brightness levels below 0.5 foot-lambert is reviewed briefly. A method of calibrating a photoelectric photometer for heterochromatic measurements in this so-called Purkinje range is described with some details given of the design of the instrument used. By arbitrarily dividing the luminous emission of a tungsten lamp into twelve overlapping spectral bands it has been possible to calibrate a photometer, using a single correction filter for the phototube. The practical advantages of such a calibration include much time saved in brightness measurements on phosphor samples of different colors.

© 1952 Optical Society of America

The Correction of Low Intensity Luminance Functions for the Purkinje Effect*

C. S. Bridgman
J. Opt. Soc. Am. 42(11) 832-836 (1952)

The Photometry of Solar Eclipse Phenomena

Clayton H. Sharp, S. McK. Gray, W. F. Little, and H. J. Eckweiler
J. Opt. Soc. Am. 23(7) 234-245 (1933)

A Physical Comparator for the Color Temperatures of Incandescent Lamps*

E. J. King, A. E. Snider, and F. Hamburger
J. Opt. Soc. Am. 42(3) 178-181 (1952)

A Physical Photometer

Ray P. Teele
J. Opt. Soc. Am. 31(11) 696-704 (1941)

Photometric Evaluation of Luminous Materials for Naval Uses

W. S. Plymale and L. H. Dawson
J. Opt. Soc. Am. 39(8) 712-713 (1949)