REPRODUCTION OF ILLUSTRATIONS 



which is an exact duplicate of the original plate, can now 

 be strengthened by pouring lead or type-metal over its 

 posterior surface, and is then ready for mounting type- 

 high and printing. 



THREE-COLOR PROCESS OF REPRODUCTION 



Perhaps the most wonderful result of the discovery 

 of reproducing pictures by the half-tone process is the 

 possibility of reproducing pictures in color by the com- 

 paratively simple process of superimposing three half- 

 tone blocks successively upon a surface of color. The 

 underlying principle, which is the basis of all three-color 

 work, is the well-known fact that all colors, and all 

 shades of color, may be produced by proper blending 

 of the three primary colors, red, blue, and yellow. 

 This is of course not apparent to the sense of sight, and 

 the ordinary painting, with its purples, greens, and 

 browns, to say nothing of the blacks and whites, seems 

 to be an aggregation of scores of colors having little re- 

 lation to each other. But as a matter of fact this is an 

 optical illusion, the seemingly endless varieties of colors 

 being simply blendings in certain proportions of the 

 three primary colors. This optical illusion is no more 

 wonderful than the fact that ordinary white light, which 

 appears to have no color at all, is in reality a blending 

 of many colors; but from the nature of the case it is 

 more tangible. 



As early as 1861 the possibility of producing any 

 desired color by superimposing the primary colors in 

 exactly the right proportions was suggested by the 



[MI] 



