Abstract

Lowry’s results (1931) for brightness discrimination have been confirmed, his conclusion extended, and his recommendation amplified. The results of the present experiment, for example, show clearly that the root-mean-square departure σ_ΔI is directly proportional to ΔI. (This is here called Crozier’s law.) Moreover, since ΔI is known to vary inversely with the size of the retinal field, the use of a test field which produces a large retinal area (central fixation) is to be recommended for increased precision in photometric work.

© 1937 Optical Society of America

The Photometric Sensibility of the Eye and the Precision of Photometric Observations

E. M. Lowry
J. Opt. Soc. Am. 21(2) 132-136 (1931)

Photometric Discrimination with a Diffuse Boundary*

W. E. Knowles Middleton
J. Opt. Soc. Am. 27(3) 112-116 (1937)

The Precision of Photometric Measurements

F. K. Richtmyer and E. C. Crittenden
J. Opt. Soc. Am. 4(5) 371-387 (1920)

The Visibility of Radiation at Low Intensities*

K. S. Weaver
J. Opt. Soc. Am. 27(1) 36-43 (1937)

A Precision, All-Purpose Microcamera1

L. C. Graton and E. B. Dane
J. Opt. Soc. Am. 27(11) 355-376 (1937)