An experimental investigation of the effect of varying bandwidth on color discrimination was undertaken. No evidence was found for any differences in sensitivity to color differences among the 5-, 10-, 20-, and 80-mµ bandwidths studied. It was concluded that for psychological research in vision less emphasis be placed on monochromatic radiation of the stimulus and more on obtaining greater luminance levels.
MICHAEL H. SIEGEL, "Discrimination of Color. III. Effect of Spectral Bandwidth," J. Opt. Soc. Am. 53, 874-877 (1963)