The Prime Colors of Human Vision Presentation, Prime Color Incorporated

Let us see whether we are led to these particular lights over the developing thought of three centuries.

HISTORY

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By 1700 mankind sensed three particular colors to be of special significance to vision. (suggested by 3-color printing, invented by LeBlon)

These “three particular colors” were first taken to be the red, yellow and blue of LeBlon’s inks (subtractive coloration).

George Palmer (1777) first suggested retinal particles of 3 kinds,

moved (vibrated?) by the three colors of light.

By 1792, Wünsch was led to red, green and violet lights by study of Newton’s work with ADDITIVE coloration.

Thomas Young (1802) re-suggested 3 types of retinal particles,
and the “principle colors” red, green and violet.

Finally,Helmholtz (1852) first correctly differentiated between additive (light) and subtractive (pigment) mixing.

So the stretch between 1700 – 1850 firmly seated the “threeness” inherent in the human visual system.

Purposes of this talk:

•1. To suggest transposition of Thomas Young’s concept from the retina to the visual system as a whole

•2. To relate visual-system spectral sensitivities to the early “three fundamental color sensations.”

•3. To stipulate that the “three principal colors” do exist in the outside world of physical radiation

•4. That they are to be identified with the three “prime colors”, of 30 years standing, near 450 nm, 530 nm, and 610 nm

•5. That these 3 spectral lights mark the maxima of the visual system’s three independent spectral sensitivities

•6. That, finally, these unique spectral sensitivities of the visual system are what Young discovered, as the “consequence of its organization”

David Wright was probably the first to suggest that the three intersections of the SPDs of matching lights are positioned in wavelength by the visual-system sensitivities

These are three matching yellowish lights reflected from, say, a blouse, skirt, and shoes, all of which are visually the same tan color, but have had to be colored by different colorants (because e.g, leather won’t take the same colorants as will silk.

Blue, white and tan lights, that match exactly within the group, and show that the intersections of the spectral power distributions always fall at the peaks of the visual sensitivities.

Showing that Color Rendering Index of matching white illuminations, each a mixture of three spectral lights, goes to pot if even one of the triad that mixes to make the white light strays from the prime colors.

CIE Luminous efficiency function

(1924)