Complementary colors are pairs of colors which, when combined or mixed, cancel each other out (lose chroma) by producing a grayscale color like white or black.Shorter Oxford English Dictionary, 5th Edition, Oxford University Press (2002) "A color that combined with a given color makes white or black." When two highly chromatic complementary colors are placed next to each other, they create a strong contrast. Complementary colors may also be called "opposite colors".
Which pairs of colors are considered complementary depends on the color model that one uses: Modern color theory uses either the RGB additive color model or the CMY subtractive color model, and in these, the complementary pairs are red–cyan, green–magenta (one of the purples), and blue–yellow. In the traditional RYB color model, the complementary color pairs are red–green, yellow–purple, and blue–orange. Opponent process theory suggests that the most contrasting color pairs are red–green and blue–yellow. The black–white color pair is common to all the above theories.
These contradictions stem in part from the fact that traditional color theory has been superseded by empirically-derived modern color theory, and in part from the imprecision of language. For example, blue can be the complement of both yellow and orange because a wide range of hues, from cyan to blue-violet, are called blue in English.
In different color models Traditional color model The traditional color wheel model dates to the 18th century and is still used by many artists today. This model designates red, yellow, and blue as primary colors with the primary–secondary complementary pairs of red–green, blue-orange, and yellow–purple.
In this traditional scheme, a complementary color pair contains one primary color (yellow, blue, or red) and a secondary color (green, purple or orange). The complement of any primary color can be made by combining the two other primary colors. For example, to achieve the complement of yellow (a primary color) one could combine red and blue. The result would be purple, which appears directly across from yellow on the color wheel. Continuing with the color wheel model, one could then combine yellow and purple, which essentially means that all three primary colors would be present at once. Since paints work by absorbing light, having all three primaries together produces a black or gray color (see subtractive color). In more recent painting manuals, the more precise subtractive primary colors are magenta, cyan, and yellow.for example, see Isabelle Roelofs and Fabien Petillion, La Couleur expliquée aux artistes, p. 16
Complementary colors can create some striking optical effects. The shadow of an object appears to contain some of the complementary color of the object. For example, the shadow of a red apple will appear to contain a little blue-green. This effect is often copied by painters who want to create more luminous and realistic shadows. If one stares at a color for about 45 seconds, and then looks at a white paper or wall, they will briefly see an afterimage of the object in its complementary color.
Placed side-by-side as tiny dots, in partitive color mixing, complementary colors appear gray.
Colors produced by light The RGB color model, invented in the 19th century and fully developed in the 20th century, uses combinations of red, green, and blue light against a black background to make the colors seen on a computer monitor or television screen. In the RGB model, the primary colors are red, green, and blue. The complementary primary–secondary combinations are red–cyan, green–magenta, and blue–yellow. In the RGB color model, the light of two complementary colors, such as red and cyan, combined at full intensity, will make white light, since two complementary colors contain light with the full range of the spectrum. If the light is not fully intense, the resulting light will be gray.
In some other color models, such as the HSV color space, the neutral colors (white, grays, and black) lie along a central axis. Complementary colors (as defined in HSV) lie opposite each other on any horizontal cross-section. For example, in the CIE 1931 color space a color of a "dominant" wavelength can be mixed with an amount of the complementary wavelength to produce a neutral color (gray or white).
Color printing
Color printing, like painting, also uses subtractive colors, but the complementary colors are different from those used in painting. As a result, the same logic applies as to colors produced by light. Color printing uses the CMYK color model, making colors by overprinting cyan, magenta, yellow, and black ink. In printing the most common complementary colors are magenta–green, yellow–blue, and cyan–red. In terms of complementary/opposite colors, this model gives exactly the same result as using the RGB model. Black is added when needed to make the colors darker.
In theory and art In color theory The effect that colors have upon each other has been noted since antiquity. In his essay On Colors, Aristotle observed that "when light falls upon another color, then, as a result of this new combination, it takes on another nuance of color".On Colors or De Coloribus (793b) cited in John Gage, Couleur et Culture, pg. 13 Saint Thomas Aquinas had written that purple looked different next to white than it did next to black, and that gold looked more striking against blue than it did against white; the Italian Renaissance architect and writer Leon Battista Alberti observed that there was harmony (coniugatio in Latin, and amicizia in Italian) between certain colors, such as red–green and red–blue; and Leonardo da Vinci observed that the finest harmonies were those between colors exactly opposed (retto contrario), but no one had a convincing scientific explanation why that was so until the 18th century.
In 1704, in his treatise on optics, Isaac Newton devised a circle showing a spectrum of seven colors. In this work and in an earlier work in 1672, he observed that certain colors around the circle were opposed to each other and provided the greatest contrast; he named red and blue (modern cyan), yellow and violet, and green and "a purple close to scarlet".John Gage, Couleur et culture, pg. 172.
In the following decades, scientists refined Newton's color circle, eventually giving it twelve colors: the three primary colors (yellow, blue, and red); three secondary colors (green, purple and orange), made by combining primary colors; and six additional tertiary colors, made by combining the primary and secondary colors.
In two reports read before the Royal Society (London) in 1794, the American-born British scientist Benjamin Thompson, Count Rumford (1753–1814), coined the term complement to describe two colors that, when mixed, produce white. While conducting photometric experiments on factory lighting in Munich, Thompson noticed that an "imaginary" blue color was produced in the shadow of yellow candlelight illuminated by skylight, an effect that he reproduced in other colors by means of tinted glasses and pigmented surfaces. He theorized that "To every color, without exception, whatever may be its hue or shade, or however it may be compounded, there is another in perfect harmony to it, which is its complement, and may be said to be its companion." He also suggested some possible practical uses of this discovery. "By experiments of this kind, which might easily be made, ladies may choose ribbons for their gowns, or those who furnish rooms may arrange their colors upon principles of the most perfect harmony and of the purest taste. The advantages that painters might derive from a knowledge of these principles of the harmony of colors are too obvious to require illustration."Benjamin Thompson, Count Rumford, Conjectures respecting the Principle of the Harmony of Colors, The Complete Works of Count Rumford, Volume 5, pp. 67–68. (Google Books).
In the early 19th century, scientists and philosophers across Europe began studying the nature and interaction of colors. The German poet Johann Wolfgang von Goethe presented his own theory in 1810, stating that the two primary colors were those in the greatest opposition to each other, yellow and blue, representing light and darkness. He wrote that "Yellow is a light which has been dampened by darkness; blue is a darkness weakened by light."Goethe (1810), Theory of Colors, paragraph 502. Out of the opposition of blue and yellow, through a process called "steigerung", or "augmentation" a third color, red, was born. Goethe also proposed several sets of complementary colors which "demanded" each other. According to Goethe, "yellow 'demands' violet; orange [demands] blue; purple [demands] green; and vice versa".Goethe, Theory of Colours, trans. Charles Lock Eastlake, Cambridge, MA: MIT Press, 1982. Goethe's ideas were highly personal and often disagreed with other scientific research, but they were highly popular and influenced some important artists, including J. M. W. Turner.John Gage, Couleur et Culture, pp. 201–203.
At about the same time that Goethe was publishing his theory, a British physicist, doctor and Egyptologist, Thomas Young (1773–1829), showed by experiments that it was not necessary to use all the colors of spectrum to create white light; it could be done by combining the light of just three colors; red, green, and blue. This discovery was the foundation of additive colors, and of the RGB color model.Isabelle Roelofs and Fabien Petillion, La couleur expliqée aux artistes, p. 14. He showed that it was possible to create magenta by combining red and blue light; to create yellow by mixing red and green light; and to create cyan, or blue-green, by mixing green and blue. He also found that it was possible to create virtually any other color by modifying the intensity of these colors. This discovery led to the system used today to create colors on a computer or television display. Young was also the first to propose that the retina of the eye contained nerve fibers which were sensitive to three different colors. This foreshadowed the modern understanding of color vision, in particular the finding that the eye does indeed have three color receptors which are sensitive to different wavelength ranges.
At about the same time as Young discovered additive colors, another British scientist, David Brewster (1781–1868), the inventor of the kaleidoscope, proposed a competing theory that the true primary colors were red, yellow, and blue, and that the true complementary pairs were red–green, blue–orange, and yellow–purple. Then a German scientist, Hermann von Helmholtz, (1821–1894), resolved the debate by showing that colors formed by light, additive colors, and those formed by pigments, subtractive colors, did in fact operate by different rules, and had different primary and complementary colors.Isabelle Roelofs and Fabien Petillion, La couleur expliquée aux artistes, p. 18.