Magnitude estimations of brightness for lights of different wavelengths.

Abstract

Summary A magnitude estimation procedure was used to obtain brightness estimations for 16 subjects with the use of lights of different wavelengths. Color filters were combined to produce wavelength bands of 460–470 nm, 520–540 nm, 590–610 nm, and 680–700 nm and light intensity was varied over a wide range by neutral density filters. The results were four power functions whose exponents decreased monotonically from .37 for the short wavelength band to .28 for the long wavelength band. These exponents are compared to the exponent of .33 typically obtained for white light. Treating the exponents as linearly related to wavelength yields an equation predicting the exponent for any wavelength within the range tested.