upon the red cloth, sees the color red because red wave lengths are not 

 absorbed but reflected and perceived by the viewer. Exactly how this 

 sensation is recei\ed and transmitted by the himian nervous system is not 

 known, although there are a number of theories on this aspect of color 

 perception. The classic theory of the natiu-e of color was more fully inter- 

 preted for the layman by Sargent (1964). Land's interesting new concept of 

 color vision is also recommended for those who wish to pursue the subject 

 further (1964). 



The relationship of light to colored objects is of great concern to the dyer 

 to whom a colored textile will appear quite different under varying light 

 conditions. For example, the red of the cloth in question may appear clear 

 and pure in daylight, yellow red in yellowish incandescent light, and bluish 

 red under blued fluorescent lighting. These effects cay be predicted since 

 substances can only reflect rays present in the light that falls on them. 

 We know that daylight, being white light, contains all wave lengths, so 

 all wave lengths except red will be absorbed. Only red will be reflected, 

 thus we will perceive the cloth as pure red. Incandescent light is a weak 

 yellow light; thus the light waves of yellow red will be reflected from the 

 surface of the cloth. The same will be true of the slightly blued fluorescent 

 light which will allow the blue-red light waves to be reflected. If a strong 

 blue-green light almost devoid of i^ed were turned on the red cloth, the 

 object could reflect almost no red and would appear black under the new 

 light. This would explain why two "perfectly matched" colors will appear 

 different under differing light conditions. It also suggests that colors can be 

 modified by clever use of lighting. 



Mixing Colors 



Most of the dyer's everyday problems will concern colored textiles, 

 rather than colored light. Although identifying and describing color is 

 as elusive as trying to describe musical sound, color theorists have succeeded 

 in developing systems which enable dyers to communicate their ideas. 



The systems vary greatly, but most have in common the notion that 

 all colors possess three qualities: hue, value, intensity. To illustrate this 

 point, you might try painting or dyeing a green swatch, roughly matching 

 a green I am thinking of. If you dye a dark, dull yellowed green it will be 

 incorrect. A dark, bright yellow green will also be incorrect. My green is 

 light, bright and close to blue green. Your next comment would be that you 

 were not supplied with an adequate description of the particular color 

 requested. This is true because the hue or color name alone did not give 

 us any idea of the value and intensity of this special green. Any color 

 description omitting these two qualities would be too vague to be useful. 



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