Color theory, or more specifically traditional color theory, is a historical body of knowledge describing the behavior of colors — namely in color mixing, color contrast effects, color harmony, color schemes and color symbolism. Color theory and color science both study color and its existence. Traditional color theory tends to be more subjective and have artistic applications, while color science tends to be more objective and have functional applications, such as in chemistry, astronomy or color reproduction. However, there is much intertwining between the two throughout history, and they tend to aid each other in their own evolutions.
Color theory can be considered a science unto itself that uses the relationship between human color perception and the interactions of colors together to build their palettes, schemes, and color mixes. Importantly, color theory relies upon objective standards in-order to be consistent in color mixing and presentation – i.e. to achieve the ideal color and effect, your ratios of colors must be consistent and often exact. As for functional applications, color theory, in tandem with color science, is what allows humans to achieve ideal camouflage, design paints that disperse more heat, and is often used by theme parks like Disney to achieve their ideal aesthetic.
Color theory dates back at least as far as Aristotle's treatise On Colors and Bharata's Nāṭya Shāstra. A formalization of "color theory" began in the 18th century, initially within a partisan controversy over Isaac Newton's theory of color (Opticks, 1704), followed by what we considered to be "primary colors", continuing onward for centuries with multiple artists-turned-scientists, and vice versa, putting forth their own color wheels and color theories.
By the end of the 19th century, a schism had formed between color theory and color science due to the schism in humanities and traditional sciences, alongside the rise of Munsell color theory. Jonathan C. Fish, among others, have talked about how contemporary color science and color art are mostly deviated from each other despite having enough reason to exist through united and collaborative efforts, being symptomatic more of "disoriented culture" rather than "intrinsic incompatibility".
History of color theory Color theory is rooted in antiquity, with early musings on color in Aristotle's (d. 322 BCE) On Colors and Ptolemy's (d. 168 CE) Optics. The Nāṭya Shāstra (d. 200 BCE) composed in Ancient India, had an early, functional theory of color, considering four colors as primary, black, blue, yellow and red. It also describes the production of derived colors from primary colors.
The influence of light on color was investigated and revealed further by al-Kindi (d. 873) and Ibn al-Haytham (d. 1039). Ibn Sina (d. 1037), Nasir al-Din al-Tusi (d. 1274), and Robert Grosseteste (d. 1253) discovered that contrary to the teachings of Aristotle, there are multiple color paths to get from black to white. More modern approaches to color theory principles can be found in the writings of Leone Battista Alberti (c. 1435) and the notebooks of Leonardo da Vinci (c. 1490). In 1613, François d'Aguilon in his book of optics introduced the idea of a three-primary color based system, based in red, yellow, and blue (RYB).
Isaac Newton (d. 1727) worked extensively on color theory, helping and developing his own theory from stating the fact that white light is composed of a spectrum of colors, and that color is not intrinsic to objects, but rather arises from the way an object reflects or absorbs different wavelengths. His 1672 paper on the nature of white light and colors forms the basis for all work that followed on color and color vision.
The RYB color model (based on red-blue-yellow) became the foundation of 18th-century theories of color vision, as the fundamental sensory qualities that are blended in the perception of all physical colors, and conversely, in the physical mixture of pigments or dyes. These theories were enhanced by 18th-century investigations of a variety of purely psychological color effects, in particular the contrast between "complementary" or opposing hues that are produced by color afterimages and in the contrasting shadows in colored light. These ideas and many personal color observations were summarized in two founding documents in color theory: the Theory of Colours (1810) by the German poet Johann Wolfgang von Goethe, and The Law of Simultaneous Color Contrast (1839) by the French industrial chemist Michel Eugène Chevreul. Charles Hayter published A New Practical Treatise on the Three Primitive Colours Assumed as a Perfect System of Rudimentary Information (London 1826), in which he described how all colors could be obtained from just three.
Physiological theories of color started in the early 19th century with scientist Thomas Young. He hypothetized that humans could only perceive three primary colors (trichromacy) and combine them internally. Later Hermann von Helmholtz, based on Young's work, postulated that humans had three different cone cells for red, green and blue (RGB). This became known as Young–Helmholtz theory. On this basis the quantitative description of the color mixture or colorimetry developed in the early 20th century, along with a series of increasingly sophisticated models of color space and color perception, such as the opponent process theory.
Across the same period, industrial chemistry radically expanded the color range of lightfast synthetic pigments, allowing for substantially improved saturation in color mixtures of dyes, paints, and inks. It also created the dyes and chemical processes necessary for color photography. As a result, three-color printing became aesthetically and economically feasible in mass printed media, and the artists' color theory was adapted to primary colors most effective in inks or photographic dyes: cyan, magenta, and yellow (CMY). (In printing, dark colors are supplemented by black ink, called "key," to make the CMYK system; in both printing and photography, white is provided by the color of the paper.) These CMY primary colors were reconciled with the RGB primaries, and subtractive color mixing with additive color mixing, by defining the CMY primaries as substances that absorbed only one of the retinal primary colors: cyan absorbs only red (−R+G+B), magenta only green (+R−G+B), and yellow only blue-violet (+R+G−B). CMYK, or process, color printing is meant as an economical way of producing a wide range of colors for printing, but is deficient in reproducing certain colors, notably orange and slightly deficient in reproducing purples. A wider range of colors can be obtained with the addition of other colors to the printing process, such as in Pantone's Hexachrome printing ink system (six colors), among others.
For much of the 19th century artistic color theory either lagged behind scientific understanding or was augmented by science books written for the lay public, in particular Modern Chromatics (1879) by the American physicist Ogden Rood, and early color atlases developed by Albert Munsell (Munsell Book of Color, 1915, see Munsell color system) and Wilhelm Ostwald (Color Atlas, 1919). Major advances were made in the early 20th century by artists teaching or associated with the German Bauhaus, in particular Wassily Kandinsky, Johannes Itten, Faber Birren and Josef Albers, whose writings mix speculation with an empirical or demonstration-based study of color design principles.
Color mixing
One of the earliest purposes of color theory was to establish rules governing the mixing of pigments.
Traditional color theory was built around "pure" or ideal colors, characterized by different sensory experiences rather than attributes of the physical world. This has led to several inaccuracies in traditional color theory principles that are not always remedied in modern formulations. Another issue has been the tendency to describe color effects holistically or categorically, for example as a contrast between "yellow" and "blue" conceived as generic colors instead of the three color attributes generally considered by color science: hue, chroma and value.These confusions are partly historical and arose in scientific uncertainty about color perception that was not resolved until the late 19th century when artistic notions were already entrenched. They also arise from the attempt to describe the highly contextual and flexible behavior of color perception in terms of abstract color sensations that can be generated equivalently by any visual media.
Primary colors
Traditional color theories asserted that the three pure primary colors could not be created through mixing, but could be used to mix all possible colors. These are sometimes considered inaccurately as red, yellow and blue (RYB) for subtractive colors; or as red, green and blue (RGB) for additive colors. Ostensibly, any failure of specific paints or inks to match this ideal performance is due to the impurity or imperfection of the colorants. In contrast, modern color science does not recognize universal primary colors (no finite combination of colors can produce all other colors) and only uses primary colors to define a given color space. Any three primary colors can mix only a limited range of colors, called a gamut, which is always smaller (contains fewer colors) than the full range of colors humans can perceive. Traditional theory also held that primary colors also can't be made from other colors as they were considered inherently pure and distinct. Cyan, magenta and yellow as used in printing, are more accurate subtractive primary colors than RYB.
Secondary colors
Mixing two primary colors together will result in a secondary color. For primary colors red, yellow and blue, the secondary colors are orange, green, and purple. On the color wheel these sit between the primary colors used to create them.
Complementary colors
For the mixing of colored light, Isaac Newton's color wheel is often used to describe complementary colors, which are colors that cancel each other's hue to produce an achromatic (white, gray or black) light mixture. Newton offered as a conjecture that colors exactly opposite one another on the hue circle cancel out each other's hue; this concept was demonstrated more thoroughly in the 19th century. Some examples of complementary colors are red and green, violet and yellow, and blue and orange.
A key assumption in Newton's hue circle was that the "fiery" or maximum saturated hues are located on the outer circumference of the circle, while achromatic white is at the center. Then the saturation of the mixture of two spectral hues was predicted by the straight line between them; the mixture of three colors was predicted by the "center of gravity" or centroid of three triangle points, and so on.
According to traditional color theory based on subtractive primary colors and the RYB color model, yellow mixed with purple, orange mixed with blue, or red mixed with green produces an equivalent gray and are the painter's complementary colors. In 1918, Bonnie Snow and Hugo Froehlich discussed how the subtractive color method can be used to find color triads based on proportions of RYB colors present. They emphasize the importance of not just theorizing about color, but actually using this knowledge of complimentary colors to make the world more beautiful.