matic colors, the strongest tint will be produced when the colors bear a close relation to each other; for example try red and orange, orange and yellow, yellow and green, green and blue, etc.
The foregoing experiments, in our judgment, tends to disprove the theory advocated by Young, Helmholtz, Maxwell, Church, Rood, and others, that red, green, and blue, are the primary color sensations; also the theory of some writers who claim that red, green, and violet, are the primaries. These experiments really strengthen the theory advocated by Brewster and Chevreul, that red, yellow, and blue, are the true primary colors.
In the selection or use of colors we must not lose sight of the fact that any object which is looked at immediately after viewing a colored surface, will be slightly changed in color by the complement of the color of that surface. For example, say we have been looking at a bright sea-green color and we suddenly look upon a yellow surface; as red is the complement of sea-green, the yellow will be slightly changed by red toward orange. We again look upon the sea-green color for some minutes, and then suddenly look upon a blue object; in this case the red will change the blue toward violet. Again, we look at the sea-green for a few minutes, and then suddenly look upon a black object; in this case the black will be changed toward brown, because red over black makes brown.
If a black object be viewed upon a white surface, and then the eye is suddenly shifted to a white surface, there will be seen a clear white figure surrounded by gray. If a white object be viewed upon a black surface, and then the eye is suddenly shifted to a black surface, there will be seen a deep black figure surrounded by a grayish black.
In the use of colors we must always keep in mind the fact that any color occupying a small area of surface, when surrounded by another color occupying a much larger surface, will be strongly
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