Black is a color that results from the absence or complete absorption of visible light. It is an achromatic color, without hue, like white and grey. It is often used symbolically or figuratively to represent darkness. Black and white have often been used to describe opposites such as good and evil, the Dark Ages versus Age of Enlightenment, and night versus day. Since the Middle Ages, black has been the symbolic color of solemnity and authority, and for this reason it is still commonly worn by judges and magistrates.
Blue is one of the three primary colours in the RYB colour model, as well as in the RGB (additive) colour model. It lies between violet and cyan on the spectrum of visible light. The term blue generally describes colours perceived by humans observing light with a dominant wavelength that's between approximately 450 and 495 nanometres. Most blues contain a slight mixture of other colours; azure contains some green, while ultramarine contains some violet. The clear daytime sky and the deep sea appear blue because of an optical effect known as Rayleigh scattering. An optical effect called the Tyndall effect explains blue eyes. Distant objects appear more blue because of another optical effect called aerial perspective.
Green is the color between cyan and yellow on the visible spectrum. It is evoked by light which has a dominant wavelength of roughly 495–570 nm. In subtractive color systems, used in painting and color printing, it is created by a combination of yellow and cyan; in the RGB color model, used on television and computer screens, it is one of the additive primary colors, along with red and blue, which are mixed in different combinations to create all other colors. By far the largest contributor to green in nature is chlorophyll, the chemical by which plants photosynthesize and convert sunlight into chemical energy. Many creatures have adapted to their green environments by taking on a green hue themselves as camouflage. Several minerals have a green color, including the emerald, which is colored green by its chromium content.
Indigo is a term used for a number of hues in the region of blue. The word comes from the ancient dye of the same name. The term "indigo" can refer to the color of the dye, various colors of fabric dyed with indigo dye, a spectral color, one of the seven colors of the rainbow as described by Newton, or a region on the color wheel, and can include various shades of blue, ultramarine, and green-blue. Since the web era, the term has also been used for various purple and violet hues identified as "indigo", based on use of the term "indigo" in HTML web page specifications.
Red is the color at the long wavelength end of the visible spectrum of light, next to orange and opposite violet. It has a dominant wavelength of approximately 625–740 nanometres. It is a primary color in the RGB color model and a secondary color in the CMYK color model, and is the complementary color of cyan. Reds range from the brilliant yellow-tinged scarlet and vermillion to bluish-red crimson, and vary in shade from the pale red pink to the dark red burgundy.
Yellow is the color between green and orange on the spectrum of light. It is evoked by light with a dominant wavelength of roughly 575–585 nm. It is a primary color in subtractive color systems, used in painting or color printing. In the RGB color model, used to create colors on television and computer screens, yellow is a secondary color made by combining red and green at equal intensity. Carotenoids give the characteristic yellow color to autumn leaves, corn, canaries, daffodils, and lemons, as well as egg yolks, buttercups, and bananas. They absorb light energy and protect plants from photo damage in some cases. Sunlight has a slight yellowish hue when the Sun is near the horizon, due to atmospheric scattering of shorter wavelengths.
Purple is a color similar in appearance to violet light. In the RYB color model historically used in the arts, purple is a secondary color created by combining red and blue pigments. In the CMYK color model used in modern printing, purple is made by combining magenta pigment with either cyan pigment, black pigment, or both. In the RGB color model used in computer and television screens, purple is created by mixing red and blue light in order to create colors that appear similar to violet light.
Brown is a color. It can be considered a composite color, but it is mainly a darker shade of orange. In the CMYK color model used in printing and painting, brown is usually made by combining the colors orange and black.
Magenta is a purplish-red color. On color wheels of the RGB (additive) and CMY (subtractive) color models, it is located precisely midway between blue and red. It is one of the four colors of ink used in color printing by an inkjet printer, along with yellow, cyan, and black to make all the other colors. The tone of magenta used in printing, printer's magenta, is redder than the magenta of the RGB (additive) model, the former being closer to rose.
A pigment is a powder used to add color or change visual appearance. Pigments are completely or nearly insoluble and chemically unreactive in water or another medium; in contrast, dyes are colored substances which are soluble or go into solution at some stage in their use. Dyes are often organic compounds whereas pigments are often inorganic. Pigments of prehistoric and historic value include ochre, charcoal, and lapis lazuli.
Orange is the colour between yellow and red on the spectrum of visible light. The human eyes perceive orange when observing light with a dominant wavelength between roughly 585 and 620 nanometres. In traditional colour theory, it is a secondary colour of pigments, produced by mixing yellow and red. In the RGB colour model, it is a tertiary colour. It is named after the fruit of the same name.
Complementary colors are pairs of colors which, when combined or mixed, cancel each other out by producing a grayscale color like white or black. When placed next to each other, they create the strongest contrast for those two colors. Complementary colors may also be called "opposite colors". They are so called, because between the two shades, the set of the three primaries, red, blue and yellow is completed.
Subtractive color or subtractive color mixing predicts the spectral power distribution of light after it passes through successive layers of partially absorbing media. This idealized model is the essential principle of how dyes and pigments are used in color printing and photography, where the perception of color is elicited after white light passes through microscopic "stacks" of partially absorbing media allowing some wavelengths of light to reach the eye and not others, and also in painting, whether the colors are mixed or applied in successive layers.
Grey or gray is an intermediate color between black and white. It is a neutral or achromatic color, meaning that it has no chroma and therefore no hue. It is the color of a cloud-covered sky, of ash, and of lead.
Scarlet is a bright red color, sometimes with a slightly orange tinge. In the spectrum of visible light, and on the traditional color wheel, it is one-quarter of the way between red and orange, slightly less orange than vermilion.
White is the lightest color and is achromatic. It is the color of objects such as snow, chalk, and milk, and is the opposite of black. White objects fully reflect and scatter all the visible wavelengths of light. White on television and computer screens is created by a mixture of red, blue, and green light. The color white can be given with white pigments, especially titanium dioxide.
Violet is a color term derived from the flower of the same name. There are numerous variations of the color violet, a sampling of which are shown below.
There are numerous variations of the color purple, a sampling of which is shown below.
A colorant is any substance that changes the spectral transmittance or reflectance of a material. Synthetic colorants are those created in a laboratory or industrial setting. The production and improvement of colorants was a driver of the early synthetic chemical industry, in fact many of today's largest chemical producers started as dye-works in the late 19th or early 20th centuries, including Bayer AG(1863). Synthetics are extremely attractive for industrial and aesthetic purposes as they have they often achieve higher intensity and color fastness than comparable natural pigments and dyes used since ancient times. Market viable large scale production of dyes occurred nearly simultaneously in the early major producing countries Britain (1857), France (1858), Germany (1858), and Switzerland (1859), and expansion of associated chemical industries followed. The mid-nineteenth century through WWII saw an incredible expansion of the variety and scale of manufacture of synthetic colorants. Synthetic colorants quickly became ubiquitous in everyday life, from clothing to food. This stems from the invention of industrial research and development laboratories in the 1870s, and the new awareness of empirical chemical formulas as targets for synthesis by academic chemists. The dye industry became one of the first instances where directed scientific research lead to new products, and the first where this occurred regularly.
The color blue has been important in culture, politics, art and fashion since ancient times. Blue was used in ancient Egypt for jewelry and ornament. In the Renaissance, blue pigments were prized for paintings and fine blue and white porcelain. In the Middle Ages, deep rich blues made with cobalt were used in stained glass windows. In the 19th century, the color was often used for military uniforms and fashion.