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 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.
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 435 nanometers. The color's name is derived from the Viola genus of flowers.
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.
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.
Georges Pierre Seurat was a French post-Impressionist artist. He devised the painting techniques known as chromoluminarism and pointillism and used conté crayon for drawings on paper with a rough surface.
A Sunday Afternoon on the Island of La Grande Jatte was painted from 1884 to 1886 and is Georges Seurat's most famous work. A leading example of pointillist technique, executed on a large canvas, it is a founding work of the neo-impressionist movement. Seurat's composition includes a number of Parisians at a park on the banks of the River Seine. It is held in the collection of the Art Institute of Chicago.
Umber is a natural earth pigment consisting of iron oxide and manganese oxide; it has a brownish color that can vary among shades of yellow, red, and green. Umber is considered one of the oldest pigments known to humans, first seen in Ajanta Caves in 200 BC – 600 AD. Umber's advantages are its highly versatile color, warm tone, and quick drying abilities. While some sources indicate that umber's name comes from its geographic origin in Umbria, other scholars suggest that it derives from the Latin word umbra, which means "shadow". The belief that its name derives from the word for shadow is fitting, as the color helps create shadows. The color is primarily produced in Cyprus. Umber is typically mined from open pits or underground mines and ground into a fine powder that is washed to remove impurities. In the 20th century, the rise of synthetic dyes decreased the demand for natural pigments such as umber.
Oil paint is a type of slow-drying paint that consists of particles of pigment suspended in a drying oil, commonly linseed oil. The viscosity of the paint may be modified by the addition of a solvent such as turpentine or white spirit, and varnish may be added to increase the glossiness of the dried oil paint film. The addition of oil or alkyd medium can also be used to modify the viscosity and drying time of oil paint. Oil paints were first used in Asia as early as the 7th century AD and can be seen in examples of Buddhist paintings in Afghanistan. Oil-based paints made their way to Europe by the 12th century and were used for simple decoration, but oil painting did not begin to be adopted as an artistic medium there until the early 15th century. Common modern applications of oil paint are in finishing and protection of wood in buildings and exposed metal structures such as ships and bridges. Its hard-wearing properties and luminous colors make it desirable for both interior and exterior use on wood and metal. Due to its slow-drying properties, it has recently been used in paint-on-glass animation. The thickness of the coat has considerable bearing on the time required for drying: thin coats of oil paint dry relatively quickly.
Neo-Impressionism is a term coined by French art critic Félix Fénéon in 1886 to describe an art movement founded by Georges Seurat. Seurat's most renowned masterpiece, A Sunday Afternoon on the Island of La Grande Jatte, marked the beginning of this movement when it first made its appearance at an exhibition of the Société des Artistes Indépendants in Paris. Around this time, the peak of France's modern era emerged and many painters were in search of new methods. Followers of Neo-Impressionism, in particular, were drawn to modern urban scenes as well as landscapes and seashores. Science-based interpretation of lines and colors influenced Neo-Impressionists' characterization of their own contemporary art. The Pointillist and Divisionist techniques are often mentioned in this context, because they were the dominant techniques in the beginning of the Neo-Impressionist movement.
Cerulean, also spelled caerulean, is a variety of the hue of blue that may range from a light azure blue to a more intense sky blue, and may be mixed as well with the hue of green. The first recorded use of cerulean as a colour name in English was in 1590. The word is derived from the Latin word caeruleus, "dark blue, blue, or blue-green", which in turn probably derives from caerulum, diminutive of caelum, "heaven, sky".
Cobalt blue is a blue pigment made by sintering cobalt(II) oxide with aluminum(III) oxide (alumina) at 1200 °C. Chemically, cobalt blue pigment is cobalt(II) oxide-aluminium oxide, or cobalt(II) aluminate, CoAl2O4. Cobalt blue is lighter and less intense than the (iron-cyanide based) pigment Prussian blue. It is extremely stable and historically has been used as a coloring agent in ceramics (especially Chinese porcelain), jewelry, and paint. Transparent glasses are tinted with the silica-based cobalt pigment "smalt".
Naples yellow, also called antimony yellow or lead antimonate yellow, is an inorganic pigment that largely replaced lead-tin-yellow and has been used in European paintings since the seventeenth century. While the mineral orpiment is considered to be the oldest yellow pigment, Naples yellow, like Egyptian blue, is one of the oldest known synthetic pigments. Naples yellow was used in ancient Egypt and Mesopotamia, finding widespread application during the Hellenistic and Roman periods. Prior to its earliest occurrences in European paintings, the pigment was commonly employed in pottery, glazes, enamels, and glass. The pigment ranged in hue from a muted, earthy, reddish yellow to a bright light yellow.
Divisionism, also called chromoluminarism, is the characteristic style in Neo-Impressionist painting defined by the separation of colors into individual dots or patches that interact optically.
Aureolin is a pigment sparingly used in oil and watercolor painting. Its color index name is PY40. It was first made in 1831 by Nikolaus Wolfgang Fischer in Breslau characterizing it as "Doppelsalze" or double-salts and its chemical composition is potassium cobaltinitrite. He characterized it again and wrote more extensively about it in 1842, naming it "Salpetrichtsaures Kobaltoxydkali". In 1851–1852, Edouard Saint-Evre synthesized cobalt yellow independently. He is credited with the introduction of cobalt yellow as an artists pigment. The investigation by Gates gives the exact modern procedures for the preparation of aureolin and also the methods for its identification in paintings.
Rose madder is a red paint made from the pigment madder lake, a traditional lake pigment extracted from the common madder plant Rubia tinctorum.
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.
YInMn Blue, also known as Oregon Blue or Mas Blue, is an inorganic blue pigment that was discovered by Mas Subramanian and his (then) graduate student, Andrew Smith, at Oregon State University in 2009. The pigment is noteworthy for its vibrant, near-perfect blue color and unusually high NIR reflectance. The chemical compound has a unique crystal structure in which trivalent manganese ions in the trigonal bipyramidal coordination are responsible for the observed intense blue color. Since the initial discovery, the fundamental principles of colour science have been explored extensively by the Subramanian research team at Oregon State University, resulting in a wide range of rationally designed novel green, purple, and orange pigments, all through intentional addition of a chromophore in the trigonal bipyramidal coordination environment.
Blue pigments are natural or synthetic materials, usually made from minerals and insoluble with water, used to make the blue colors in painting and other arts. The raw material of the earliest blue pigment was lapis lazuli from mines in Afghanistan, that was refined into the pigment ultramarine. Since the late 18th and 19th century, blue pigments are largely synthetic, manufactured in laboratories and factories.
