Abstract

Photometry has been carried on for many years by means of visual observations not because the eye is an accurate measuring instrument but because there has been no physical apparatus which would respond with sufficient accuracy to light in the same manner as the human eye. Even experienced observers may obtain markedly different results because they will not agree as to when two illuminated surfaces are equally bright. A physical photometer which “sees” light in accordance with the ICI luminosity factors has been constructed. These luminosity factors have been accepted internationally to represent the characteristics of the eye of a “standard observer.” This photometer gives results which are consistent with the ICI luminosity factors and which are more accurate than those of visual observers when the light transmissions of colored filters are measured. The construction and operation of this physical photometer are described in a paper by R. P. Teele in the National Bureau of Standards Journal of Research, 127, No. 3 (RP 1415).

© 1941 Optical Society of America

Prism and Sector Photoelectric Photometers for Determination of Concentrations in Gaseous or Liquid Systems*

Louis Harris, Jack A. Kyger, and C. Norman Sjogren
J. Opt. Soc. Am. 31(3) 263-267 (1941)

A Physical Photometer for Afocal Optical Systems*

D. B. McRae
J. Opt. Soc. Am. 35(8) 510-517 (1945)

Radiant Energy Measurements with Thermopiles

N. C. Beese
J. Opt. Soc. Am. 31(11) 705-708 (1941)

Physical Photometry in the Purkinje Range

W. S. Plymale and G. T. Hicks
J. Opt. Soc. Am. 42(5) 344-348 (1952)

A Tristimulus Photometer

George C. Sziklai
J. Opt. Soc. Am. 41(5) 321-323 (1951)