350 THE SPECIAL SENSES. 



Color Contrasts. — By color contrast is meant the influence 

 that one color field has upon a contiguous one. If, for instance, a 

 piece of blue paper is laid upon a larger yellow square, the color 

 of each of them is heightened by contrast. A piece of blue 

 paper on a blue background does not appear so saturated as when 

 placed against a yellow background. The influences of contrast 

 may be shown in a great variety of ways.* For instance, if a disc 

 like that in the illustration, Fig. 149A, is rotated rapidly, it should 

 give circles of gray, the darkest at the middle; but each circle should 

 be uniform as it is made by the fusion of a definite amount of white 

 and black. On the contrary, the appearance obtained is that repre 



Fig. 149A.— Black and white disc for ex- Fig. 149fi.— Showing the result when the 

 periment on contrast. — (Rood.) disc A is set into rapid rotation. — (Rood.) 



sented in Fig. 149B. Each circle appears darker on its outer edge 

 where it borders on a fighter circle, and lighter on its inner edge where 

 it borders on a darker circle. Similar contrasts may be obtained from 

 comparing shadows cast by yellow and white fight. If a rod be 

 arranged in a dark room so as to cast a shadow from an opening 

 admitting- daylight and one also from a lighted candle, either shadow 

 taken separately appears black, but if the two are cast side by side 

 one will appear blue, the other yellow. The shadow cast by the 

 daylight, being illuminated by the yellow candle-light, will appear 

 yellow, and the other shadow, that from the candle-light, will by 

 contrast seem quite blue. A striking instance of the effect of con- 

 trast is given, also, by the simple experiment of Mayer, illustrated 

 in Fig. 148. The gray square on the green background suffers no 

 apparent change from contrast, but if the figure is covered by a 

 sheet of white tissue paper the gray square at once takes on a red- 

 dish hue. It is evident that in all artistic and ornamental employ- 

 ment of colors this influence must be considered, and empirical 

 rules are established which indicate for the normal eye the bene- 

 ficial or the killing effect of different colors when brought into 

 juxtaposition. 



♦Rood, "Modern Chromatics," " International Scientific Series." 



