Characteristic Curves of the Human Eye

Abstract

An attempt has been made to derive characteristic curves for the human eye under various states of adaptation. Although the curves have been derived from luminance discrimination data, it has not been assumed that each discnminable step of luminance corresponds to the same sensation interval, nor has it been assumed that numbers of sensation intervals can be integrated ; the curves are therefore free from the criticisms that are often levelled against the Weber-Fechner Law. This has been accomplished by analysing luminance discrimination data from a physiological, rather than a psychological, point of view. The curves obtained are consistent both with apparent brightness and contrast data, and with electrophysiological studies, and they permit a simple quantitative explanation of the variation of luminance discrimination with field size.