Abstract
The present investigation tested the scalar additivity of luminance by generating a luminosity curve from radiances weighted by the appropriate luminosity coefficients. A Cohen multichromatic colorimeter was utilized because it presents near monochromatic spectral components of high radiance. The standard wavelengths were selected at 10-mμ intervals from 400 to 700 mμ and were specified by primaries at 470, 550, and 630 mμ. The radiance of each of these four components was then measured with a thermopile and galvanometer. These radiances were transformed to an equal energy spectrum and reduced to luminance. The luminances were then summed to test the Law of Additivity of Luminance. If the law is valid the resulting curve should be a good approximation to the CIE luminosity curve. It was found the derived curve was not a good approximation because it was displaced toward the blue portion of the spectrum. New luminosity coefficients were derived in order to produce a better fit, and the implications of these new coefficients are briefly discussed.
© 1957 Optical Society of America
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