An instrument has been developed for the systematic visual selection of color film neutrals. The light source of the instrument accurately simulates a blackbody at 4000 K for this purpose. The visual field of the instrument is circular, bipartite, in visual subtense, and is presented in a dark surround. It is estimated that the source intensity is adequate to insure a stable photopic level of adaptation in the eye of the observer with color film samples in the beam of visual density as high as 2.50.
The instrument will be used: (1) to select neutral film samples as standards for equivalent neutral color densitometry; (2) to compare the precision with which neutrals may be selected visually by real observers to that associated with the calculation of neutrals from spectrophotometric curves, assuming the characteristics of the CIE standard observer; and (3) to compare the spectrophotometric properties of neutrals selected visually with those of neutrals selected by calculation assuming the CIE standard observer.
© 1958 Optical Society of AmericaFull Article | PDF Article
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