A new precision colorimeter
P. G. Nutting · Bulletin of the Bureau of Standards · 1913
It is well known that any color may be analyzed and specified in either of two different ways : (i) In terms of three primary com- ponents, red, green, and blue (trichromatic analysis) ; or (2) in terms of wave length of dominant hue or its complementary and per cent white (monochromatic analysis) .In mathematical terms, the color point may be located by either trilinear or by polar coor- dinates.Of the three elements of color; hue, tone, and luminosity, hue and tone are determined with a colorimeter, luminosity with a photometer or a photometric part of the colorimeter.Colors to be analyzed consist of light either emitted from some source, transmitted through some selective screen, or reflected from some mat or semi-mat surface.Any of these colors to be analyzed may be either spectral or purple, according to whether or not its dominant hue lies in the visible spectrum.Any analyzing colorimeter must then be applicable to emitted, transmitted, or reflected light of either spectral or purple dominant hue.