Study on Color Rendering and Metamerism (Part 5)

Color-matching properties on the basis of metameric gray object colors were derived for Planckian radiators and CIE standard daylight illuminants with different values of correlated color temperatures with respect to the reference illuminant D65.Then, color-matching properties of CIE daylight illuminants were compared with those of fluorescent lamps, which are different kinds of reconstituted fluorescent lamps with the same chromaticity as that of D65 and four kinds of actual fluorescent lamps with high Ra values and with correlated color temperatures 4, 200 K, 5, 000 K and 5, 500 K.The results confirmed following conclusions:1) Adequateness of north skylight for color-matching work was estimated by following two reasons.a) Pretty good stability of illuminance as compared with other directions of daylight, andb) good color-matching properties of daylight illuminants irrespective of large variations in their spectral power distributions for different days of observations.(2) In the case of the reference illuminant D65., the reconstituted fluorescent lamp with the samechromaticity as D65. and with Ra=92.1 (the maximum Ra value is 94.6 for these reconstitutedfluorescent lamps) has better color-matching property than fluorescent lamps with high Ravalues (Ra=97-98) but with correlated color temperatures lower than 6, 500K.