Violet (color)

Violet is the color of light at the short wavelength end of the visible spectrum. It is one of the seven colors that Isaac Newton labeled when dividing the spectrum of visible light in 1672. Violet light has a wavelength between approximately 380 and 450 nanometers. The color's name is derived from the Viola genus of flowers.
In the RGB color model used in computer and television screens, violet is produced by mixing red and blue light, with more blue than red. In the RYB color model historically used by painters, violet is created with a combination of red and blue pigments and is located between blue and purple on the color wheel. In the CMYK color model used in printing, violet is created with a combination of magenta and cyan pigments, with more magenta than cyan. On the RGB/CMY color wheel, violet is located between blue and magenta.
Violet is closely associated with purple. In optics, violet is a spectral color, whereas purple is the color of various combinations of red and blue light, some of which humans perceive as similar to violet. In common usage, both terms are used to refer to a variety of colors between blue and red in hue.
Violet has a long history of association with royalty, originally because Tyrian purple dye was extremely expensive in antiquity. The emperors of Rome wore purple togas, as did the Byzantine emperors. At one point in history, purple bells were also used in the flag of the Sassanid Empire. During the Middle Ages, violet was worn by bishops and university professors and was often used in art as the color of the robes of the Virgin Mary. In Chinese painting, the color violet represents the "unity transcending the duality of Yin and yang" and "the ultimate harmony of the universe". In New Age thinking, purple and/or violet is associated with the crown chakra. One European study suggests that violet is the color people most often associate with extravagance, individualism, vanity and ambiguity

Etymology and definitions

The word violet as a color name derives from the Middle English and Old French violete, in turn from the Latin viola, the name of the violet flower. The first recorded use as a color name in English was in 1370.

Relationship to purple

Violet is closely associated with purple. In optics, violet is a spectral color: It refers to the color of any different single wavelength of light on the short wavelength end of the visible spectrum, whereas purple is the color of various combinations of red, blue and violet light, some of which some humans perceive as similar to violet. In common usage, both terms are used to refer to a variety of colors between blue and red in hue. Historically, violet has tended to be used for bluer hues and purple for redder hues. In the traditional color wheel used by painters, violet and purple are both placed between red and blue, with violet being closer to blue.

In science

Optics

Violet is at one end of the spectrum of visible light, between blue light, which has a longer wavelength, and ultraviolet light, which has a shorter wavelength and is not visible to humans. Violet wavelengths are between approximately 380 and 435 nanometers. The color violet appears dark because the S cones, which contribute very little to the perception of lightness, do not have a high sensitivity to violet light. The reason why to humans violet light appears slightly reddish compared to spectral blue is, according to the opponent process hypothesis of color vision, that the S-cone type contributes some red to the red-versus-green opponent channel. Computer and television screens, using the RGB color model, cannot produce spectral violet light and instead they combine blue light at high intensity with red light at less intensity.
Monochromatic lamps emitting spectral-violet wavelengths can be roughly approximated by the color named electric violet, which is a composed-light violet producing a similar effect to the human eye.

Chemistry – pigments and dyes

The earliest violet pigments used by humans, found in prehistoric cave paintings, were made from the minerals manganese and hematite. Manganese is still used today by the Aranda people, a group of indigenous Australians, as a traditional pigment for coloring the skin during rituals. It is also used by the Hopi Indians of Arizona to color ritual objects.
The most famous violet-purple dye in the ancient world was Tyrian purple, made from a type of sea snail called the murex, found around the Mediterranean.
In western Polynesia, residents of the islands made a violet dye similar to Tyrian purple from the sea urchin. In Central America, the inhabitants made a dye from a different sea snail, the purpura, found on the coasts of Costa Rica and Nicaragua. The Mayans used this color to dye fabric for religious ceremonies, and the Aztecs used it for paintings of ideograms, where it symbolized royalty.
During the Middle Ages, most artists made purple or violet on their paintings by combining red and blue pigments; usually blue azurite or lapis-lazuli with red ochre, cinnabar or minium. They also combined lake colors by mixing dye with powder; woad or indigo dye for blue and cochineal dye for red.
Orcein, or purple moss, was another common violet dye. It was known to the ancient Greeks and Hebrews, was made from a Mediterranean lichen called archil or dyer's moss, combined with an ammoniac, usually urine. Orcein began to achieve popularity again in the 19th century, when violet and purple became the color of demi-mourning, worn after a widow or widower had worn black for a certain time, before he or she returned to wearing ordinary colors.
In the 18th century, chemists in England, France and Germany began to create the first synthetic dyes. Two synthetic purple dyes were invented at about the same time. Cudbear is a dye extracted from orchil lichens that can be used to dye wool and silk, without the use of mordant. Cudbear was developed by Cuthbert Gordon of Scotland: production began in 1758, The lichen is first boiled in a solution of ammonium carbonate. The mixture is then cooled and ammonia is added and the mixture is kept damp for 3–4 weeks. Then the lichen is dried and ground to powder. The manufacture details were carefully protected, with a ten-foot high wall built around the manufacturing facility, and staff consisting of Highlanders sworn to secrecy.
French purple was developed in France at about the same time. The lichen is extracted by urine or ammonia. Then the extract is acidified, the dissolved dye precipitates and is washed. Then it is dissolved in ammonia again, the solution is heated in air until it becomes purple, then it is precipitated with calcium chloride; the resulting dye was more solid and stable than other purples.
Cobalt violet is a synthetic pigment that was invented in the second half of the 19th century, and is made by a similar process as cobalt blue, cerulean blue and cobalt green. It is the violet pigment most commonly used today by artists, along with manganese violet.
Mauveine, also known as aniline purple and Perkin's mauve, was the first synthetic organic chemical dye, discovered serendipitously during an attempt to make quinine in 1856. Its chemical name is 3-amino-2,±9-dimethyl-5-phenyl-7- phenazinium acetate.
In the 1950s, a new family of violet synthetic organic pigments called quinacridones came onto the market. They had originally been discovered in 1896, synthesized in 1936 and manufactured in the 1950s. The colors in the group range from deep red to violet in color, and have the molecular formula C₂₀H₁₂N₂O₂. They have strong resistance to sunlight and washing, and are used in oil paints, watercolors and acrylics, as well as in automobile coatings and other industrial coatings.

Zoology

Botany

In history and art

Prehistory and antiquity

Violet is one of the oldest colors used by humans. Traces of very dark violet, made by grinding the mineral manganese, mixed with water or animal fat and then brushed on the cave wall or applied with the fingers, are found in the prehistoric cave art in Pech Merle, in France, dating back about 25,000 years. It has also been found in the cave of Altamira and Lascaux. It was sometimes used as an alternative to black charcoal. Sticks of manganese, used for drawing, have been found at sites occupied by Neanderthals in France and Israel. From the grinding tools at various sites, it appears it may also have been used to color the body and to decorate animal skins.
More recently, the earliest dates on cave paintings have been pushed back farther than 35,000 years. Hand paintings on rock walls in Australia may be even older, dating back as far as 50,000 years.
Berries of the genus rubus, such as blackberries, were a common source of dyes in antiquity. The ancient Egyptians made a kind of violet dye by combining the juice of the mulberry with crushed green grapes. The Roman historian Pliny the Elder reported that the Gauls used a violet dye made from bilberry to color the clothing of slaves. These dyes made a satisfactory purple, but it faded quickly in sunlight and when washed.

Middle Ages and Renaissance

Violet and purple retained their status as the color of emperors and princes of the church throughout the long rule of the Byzantine Empire.
While violet was worn less frequently by Medieval and Renaissance kings and princes, it was worn by the professors of many of Europe's new universities. Their robes were modeled after those of the clergy, and they often wore square violet caps and violet robes, or black robes with violet trim.
Violet also played an important part in the religious paintings of the Renaissance. Angels and the Virgin Mary were often portrayed wearing violet robes. The 15th-century Florentine painter Cennino Cennini advised artists: "If you want to make a lovely violet colour, take fine lacca, ultramarine blue..." For fresco painters, he advised a less-expensive version, made of a mixture of blue indigo and red hematite.