SENSATIONS OF COLOR 



543 



complements the other, each one furnishing just what the other lacks of being 

 white, they are called complementary colors. 



The sensation of white therefore can be produced in very different ways, 

 namely, first by the simultaneous action of all the rays contained in sunlight, 

 when they occur in the same proportion as they are there mixed together, 

 and secondly by the proper mixture of two complementary colors. However 

 it is impossible for the eye to tell whether a given white is composed of all 

 the rays of the color spectrum or only of red and greenish blue, orange and 

 blue, etc. White in other words presents only quantitative differences de- 

 pendent upon different intensities of light, but bearing no relation to the color 

 tones of which it is composed. The eye therefore does not analyze: it lacks 

 entirely the ability so highly developed in the ear, of resolving a given im- 

 pression into its separate components. 



When two colors which are not complementary are mixed together, instead 

 of white we get a new color. If red and violet, the extreme colors of the 

 spectrum, are mixed we get purple, the only color tone which does not occur 

 in the spectrum. Purple is the complementary color of green (see page 542) 

 and is in every way different from the colors the mixture of which produces it. 



When two simple colors, separated from each other in the spectrum by less 

 distance than that which separates complementary colors, are mixed, we get a 

 color lying between the two and approaching white more the greater the dis- 

 tance between them, but becoming more nearly saturated the less the distance 

 between the two components. When, on the other hand, two colors separated 

 from each other by a greater distance than that which separates complementary 

 colors are mixed, one obtains purple, or some such color, which lies between one 

 of the components and the corresponding end of the spectrum. In this case 

 the mixture is the more nearly saturated the greater the distance between the 

 components, and approaches white more the less the distance between them 

 (Helmholtz). 



