Complementary Colors

Plate 31.—This plate is intended to specially illustrate a number of very interesting experiments showing that certain colors are complementary, and also the influence of colors over one another. Before giving an explanation of the experiments referred to, it is probably best to call the reader's attention to the meaning of the word complementary as applied to colors. When the mixture of any two colors produces white light they are said to be complementary. This is true of prismatic colors, but it is impossible to obtain white by the mixture of complementary colors in printing inks or paints. There is quite a difference of opinion between the best authorities as to what colors are exactly complementary. After many careful experiments we have concluded that the following colors, as represented on Plate 32, are complementary:

• Red and Sea-green.
• Yellow and Violet.
• Blue and Orange.
• Green and Red-purple.
• Purple and Yellow-green.

It is generally believed that green is the complement of red, but this belief is mainly due to the fact that it was advocated by Chevreul, the celebrated French chemist. Maxwell and Von Bezold say that blue-green is the complement of red, while Church, Rood, and others, say green-blue is its complementary. The experiment explained [below] will show that the complement of red is a color which lies about half way between green and blue, and which, for convenience, we will call sea-green, the name preferred by some writers. This color is frequently seen at night in its most brilliant state, in the show-windows of some drug stores, produced by a light shining through a glass globe filled with a solution of ammonia and sulphate of copper.

Experiments with Colors

The complement of any color can be easily obtained by looking very intently at the color selected for about one minute, and then suddenly shifting the vision to a white surface, upon which will be seen a pure tint of the complement of the color just looked at. This being true, then it follows that when we place together two colors which are complementary and view them at the same time, there will be seen when the eyes are shifted to a white surface, a tint of each color transposed—that is, the complement of one color will be the actual tint of the other; for illustration the reader will turn to Fig. 239, Plate 31, which represents red and its complement sea-green. To obtain the best results in these experiments the instructions must be followed closely.

You will now cover Figs. 240, 241, 242, and 243 with a white sheet of paper, leaving Fig. 239 and the black dot on the right exposed. Then hold your eves about twelve or fifteen inches above the page and look steadily (without winking, if you can) at the black dot in the center of Fig. 239 for a half minute; then instantly shift your eyes to the black dot on the right, and look at that a few seconds; then shift back again to the dot on Fig. 239 and look at that a half minute then again to the dot on the right for a few seconds,¹ and after repeating these movements three or four times, finally look steadily at the dot on the right, and you will see a beautiful tint of the complement of red, and also a tint of the complement of sea-green, just the size and shape of Fig. 239. The reader will observe that the red tint is below the sea-green tint, which is just the reverse of the position of the colors in Fig. 239. If the two tints produced by this experiment are similar to the actual tints of the colors which call them into view, then the colors shown in Fig. 239 are complementary. If this experiment be tried with Fig. 242, the reader will find that the complement of green is a reddish purple.

We will now show the effect of looking at a color for several minutes, then suddenly looking upon its complement for a few seconds. The result will be that the color last looked at will appear almost as brilliant as a prismatic color. First cover all of the figures except 239 and 240. Then look very intently at the black dot on Fig. 239; after the colors have become somewhat dull to the eye, suddenly shift the vision to the dot on Fig.240. The result is most pleasing, as the colors in the latter figure seem to be increased in brilliancy tenfold. The reason for this apparent change in the colors, is that after looking upon a colored object for some minutes, that part of the retina of the eye upon which the color makes an impression becomes fatigued, and the complement of that color takes its place upon the retina. It is a fact that from the instant that we first look upon any color, its complement immediately begins to take its place upon the retina of the eye, and the longer we look upon a color, the duller it will become, and the stronger its complement will appear when we look upon a white surface; and if we look upon a color which is the complement of the color first looked at, the effect is just the same as when we print a transparent red over red, or a transparent blue over blue, etc.; the color will appear much more brilliant. This experiment can be tried with Figs. 242 and 243 with a pleasing result.

We will now give an experiment for the purpose of showing that a mixture of prismatic complementary colors will produce white light. The tint which comes into view after looking at a colored object, is really the same as a prismatic color, only it is not so strong. The reader will again cover all of the figures on Plate 31 except 239 and 240. Then look at the dot on Fig. 239 for a second, then at the dot on Fig. 240 for a second, and keep shifting the eyes at regular intervals of a second each, from one to the other for a half minute; then suddenly look at the dot between the two figures, and there will be seen a clear white figure surrounded by gray. The white is produced by an equal mixture of the complements of the colors in Figs. 239 and 240 upon the retina of the eye. The reader will observe that the colors in the two figures are purposely reversed for the benefit of some of the experiments. This experiment can also be tried with Figs. 242 and 243 with a pleasing result.

If the same experiment be applied to the three primary colors properly balanced, the result will be white; also the secondaries properly balanced will produce white by this experiment.

Another experiment showing that sea-green (which is an equal mixture of green and blue) is the complement of red, is shown by mixing the spectral complements of green and blue upon the retina of the eye; see illustration below.

After shifting the eyes at regular intervals of a second each from one to the other of the black dots upon the two colors named, for a half minute, then suddenly looking at the black dot between the two, we will see a pure tint of red, which is produced by an equal mixture upon the retina, of a red-purple tint (the complement of green) with an orange tint (the complement of blue). This experiment plainly shows that the complement of red is a color which is an equal mixture of green and blue.

Maxwell, Church, and Rood all agree that blue and yellow are complementary, instead of blue and orange as advocated by Chevreul. We think that blue and orange are complementary, and that the following experiments prove the correctness of our position; see illustration below.

By looking upon the blue figure for some minutes and then suddenly shifting the vision to the dot on the right, there will be seen a pure orange tint; and if we look upon the orange figure for some minutes and then suddenly shift the vision to the dot on the left, we will see a pure blue tint; and, finally, if we shift the vision at regular intervals of a second each, from one to the other of the two colors named, for a half minute, and then suddenly look at the dot between the two, we will see a clear white figure surrounded by gray. The white is produced by an equal mixture of the complements of blue and orange upon the retina of the eye the fact that this experiment produces white, proves that the two colors are complementary.

Another very good method of finding the complement of any color is illustrated by the following experiment—orange figure [above]. Take a slip of white paper in one hand, and while looking very intently at the dot upon the orange figure, suddenly move the slip up to the dot, hold it there a few seconds, and then withdraw it for a quarter minute; repeat these movements three or four times, but while doing so, keep looking intently at the dot. Each time the slip is moved up to the dot, that part of it which covers the orange figure will show a most beautiful blue tint. This experiment also shows that blue is complementary to orange.

We will give another experiment as additional proof that orange (which is an equal mixture of red and yellow) is the complement of blue, by mixing the spectral complements of red and yellow upon the retina of the eye; see illustration [below].

After shifting the eyes at regular intervals of a second each from one to the other of the two colors named, for a half minute, then suddenly looking at the black dot between the two, we will see a pure tint of blue, which is produced by an equal mixture upon the retina, of a sea-green tint (the complement of red) with a violet tint (the complement of yellow). This experiment plainly shows that the complement of blue is a color which is an equal mixture of red and yellow.

Any two colors which are complementary will produce white when subjected to the experiment just described. If it be applied to any two colors shown in the chromatic circle which are not complementary, then the result will be different, and instead of white we will see a tint which is produced by an equal mixture of the complements of the two colors upon the retina, and which in every case lies about half way between the complements of the two colors selected. For example, say we try orange and violet—see illustration below. After shifting the eyes at regular intervals of a second each, from one to the other of the two colors named, for a half minute, then suddenly looking at the black dot between the two, we will see a pure green tint, which is an equal mixture of a blue tint (the complement of orange) with a yellow tint (the complement of violet).

By applying this experiment to different pairs of colors shown in the chromatic circle on Plate 32, we obtain the results indicated by the table [below].

We will now try sea-green and red-purple. After shifting the eyes at regular intervals of a second each, from one to the other of the two colors named, for a half minute, then suddenly looking at the black dot between the two, we will see a pure yellow tint, which is an equal mixture of a red tint (the complement of sea-green) with a green tint (the complement of red-purple). See illustration below.

It will be noticed that by the mixture of the complements of orange and violet ( blue and yellow) in the eye, we reach the same result as in the mixture of blue and yellow pigments—green. But by the mixture of the complements of sea-green and red-purple ( red and green) in the eye, we get yellow, while the mixture of red and green pigments produces brown. If the eyes are allowed to rest upon the orange twice as long as upon the violet, the result will be (when we look at the dot between the two) we will see a tint in which blue, the complement of orange, will strongly predominate; and if we allow the eyes to rest upon the violet twice as long as upon the orange, then we will see a tint in which yellow, the complement of violet, will predominate. This rule will also apply to any pair of colors given in the following table also to any pair which may be selected from the chromatic circle on Plate 32.

It is a curious fact that by the mixture of any two prismatic colors which are represented in the chromatic circle on Plate 32, the result will always be a color which lies between the two colors used. If the two colors are about equal in strength then the resulting color will be found about half way between the two; for example, by the mixture of the prismatic red and yellow we get orange, the same as in the mixture of pigments; so it is with red and blue, which produces violet; yellow and blue, which produces green. But by the mixture of the prismatic red and green we get yellow; while the mixture of red and green pigments produces brown. And by the mixture of the prismatic green and violet we get blue; while the mixture of green and violet pigments produces an olive. Also by the mixture of the prismatic orange and purple we get red; while the mixture of orange and purple pigments produces a russet.

By the mixture of prismatic colors which are complementary the result will always be white; and by the mixture of prismatic colors which are nearly complementary the resulting tint will always be nearly white. It follows then, that in the mixture of two prismatic 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 tinted with the complement of the surrounding color. For example, see Fig. 354, Plate 68; the word contrast is printed in a pure gray ink, and is exactly registered into the blue cut. The reader will perceive that where the letters are surrounded by blue they are strongly tinted with orange; but where they are surrounded by white, they show their real color—gray. Fig. 355 on the same plate shows the word contrast printed in gray and surrounded by red. In this case the gray is very strongly tinted by sea-green the complement of red.

Very brilliant colors are influenced less by surrounding colors than the more quiet ones; gray being affected more than any other color.

1. The movements described are repeated for the purpose of building up, or making stronger the complementary tint which is called into view. ↩