Colorimetric analyses of various light sources for the D-15 color vision test.

Colorimetric analyses were performed in both normal trichromatic and dichromatic color spaces to determine whether several light sources were suitable illuminants for the Farnsworth-Munsell Panel D-15 (D-15) color vision test. Results for fluorescent lamps showed that lamps with a correlated color temperature (CCT) of 7200 degrees K and a general color rendering index (GCRI) of at least 90 are acceptable substitutes for illuminant C. Predictions for filtered tungsten light indicated that lights with a color temperature near 5000 degrees K are unsuitable because of nonuniformities in the glass daylight filter transmittance. Conclusions based on these analyses are conservative because, with exception of the GCRI, color adaptation effects were not taken into account.