Heterochromatic Brightness Matching

The test wavelengths are placed in one hemifield and the reference in the other. The observer's task is to adjust the chromatic test field until it is equally bright to the reference field. The energy (radiance) of the equally bright chromatic test field is then measured with a radiometer.

This procedure is repeated for each of the test field wavelengths. The reciprocal of these radiances is plotted as a function of wavelength which produces a graph variously called a spectral sensitivity function, luminous efficiency function, relative luminance function.

Spectral Sensitivity Measurement

Table of Contents
Subject Index
Table of Contents [When not using frames]