. A text-book of physiology : for medical students and physicians . ary rapidly by projecting the image upon screens atdifferent distances. If, for instance, in obtaining the after-imageof the strips shown in Fig. 147 one moves the white paper usedto catch the image toward and away from the eye, the apparent sizevaries proportionally to its distance. Color Contrasts.—By color contrast is meant the influencethat one color field has upon a contiguous one. If, for instance, apiece of blue paper is laid upon a larger yellow square, the colorof each of them is heightened by contrast. A piece of blu
. A text-book of physiology : for medical students and physicians . ary rapidly by projecting the image upon screens atdifferent distances. If, for instance, in obtaining the after-imageof the strips shown in Fig. 147 one moves the white paper usedto catch the image toward and away from the eye, the apparent sizevaries proportionally to its distance. Color Contrasts.—By color contrast is meant the influencethat one color field has upon a contiguous one. If, for instance, apiece of blue paper is laid upon a larger yellow square, the colorof each of them is heightened by contrast. A piece of bluepaper on a blue background does not appear so saturated as whenplaced against a yellow background. The influences of contrastmay be shown in a great variety of ways.* For instance, if a disclike that in the illustration, Fig. 149A, is rotated rapidly, it shouldgive circles of gray,the darkest at the middle; but each circle shouldbe uniform as it is made by the fusion of a definite amount of whiteand black. On the contrary, the appearance obtained is that repre.
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Keywords: ., book, bookcentury1900, booksubjectmedicine, booksubjectphysiology
