Instruct: Given a question, retrieve passages that can help answer the question.
Query: When was cobalt first used for blue paint?
Cobalt blue in impure forms had long been used in Chinese porcelain,[1] but it was independently discovered as a pure alumina-based pigment by Louis Jacques Thénard in 1802.[2] Commercial production began in France in 1807. The first recorded use of cobalt blue as a color name in English was in 1777.[3] The leading world manufacturer of cobalt blue in the 19th century was Benjamin Wegner's Norwegian company Blaafarveværket ("blue colour works" in Dano-Norwegian). Germany was also famous for production, especially the blue colour works (Blaufarbenwerke) in the Ore Mountains of Saxony.
Cobalt-based blue pigments (cobalt blue) have been used since ancient times for jewelry and paints, and to impart a distinctive blue tint to glass, but the color was later thought by alchemists to be due to the known metal bismuth. Miners had long used the name "kobold ore" (German for "goblin ore") for some of the blue-pigment producing minerals; they were so named because they were poor in known metals, and gave poisonous arsenic-containing fumes when smelted. In 1735, such ores were found to be reducible to a new metal (the first discovered since ancient times), and this was ultimately named for the "kobold".
The earliest known example of cobalt aluminate glass dates to a lump from about 2000 BC in ancient Mesopotamia, very possibly intended for use as a pigment; it was rare until the modern era. Cobalt oxide smalt appears as a pigment in Egyptian pottery about five centuries later, and soon after in the Aegean region, and this is the pigment normally known as "smalt". In paintings, smalt has a tendency to lose its colour over a long period, and is little used today. However, when used in ceramics for underglaze decoration, it keeps its colour well, and is the main blue used in blue and white pottery from a wide range of dates and areas, including Chinese blue and white porcelain from the Yuan and Ming dynasties, Renaissance Italian maiolica and Delftware.
Chinese porcelain used smalt glazes from the Tang dynasty onwards, though Chinese cobalt glass is found from the Zhou dynasty (1122–221 BC). Cobalt was used as a pigment in Central Asia from the 13th century. A fragment of a mud painting in the ancient Tangut city of Khara-Khoto has been found to contain smalt, judged to be dated between the 11th and 13th centuries. A large quantity of smalt was purchased for the decoration of the gallery of Francis I of France at Fontainebleau in 1536. Smalt, normally now discoloured, is common in European paintings from the 15th to 17th centuries. For example, it is found in Hans Holbein the Younger's portrait of Sir William Butts (ca. 1540), in Michael Pacher's painting "The Early Fathers' Altar" (ca. 1483), and in the frescos of Domenico Ghirlandaio (1449–1494).
The popularity of watercolors stimulated many innovations, including heavier and more sized wove papers, and brushes (called "pencils") manufactured expressly for watercolor. Watercolor tutorials were first published in this period by Varley, Cox, and others, establishing the step-by-step painting instructions that still characterize the genre today; "The Elements of Drawing", a watercolor tutorial by English art critic John Ruskin, has been out of print only once since it was first published in 1857. Commercial brands of watercolor were marketed and paints were packaged in metal tubes or as dry cakes that could be "rubbed out" (dissolved) in studio porcelain or used in portable metal paint boxes in the field. Breakthroughs in chemistry made many new pigments available, including synthetic ultramarine blue, cobalt blue, viridian, cobalt violet, cadmium yellow, aureolin (potassium cobaltinitrite), zinc white, and a wide range of carmine and madder lakes. These pigments, in turn, stimulated a greater use of color with all painting media, but in English watercolors, particularly by the Pre-Raphaelite Brotherhood.
Its best-known pattern, "cobalt net", first appeared in 1949. The design is based on a blue net pattern that was painted on raised lines cast into the porcelain dinnerware pieces of Catherine the Great. The factory has actual examples of Catherine's dinnerware with this design. The new design pattern is a combination of intersecting lines of cobalt blue with inverted tear drops of cobalt blue (made from mineral cobalt) and 22 karat gold accents.
Cobalt is primarily used in the manufacture of magnetic, wear-resistant and high-strength alloys. The compounds cobalt silicate and cobalt(II) aluminate (CoAlO, cobalt blue) give a distinctive deep blue color to glass, ceramics, inks, paints and varnishes. Cobalt occurs naturally as only one stable isotope, cobalt-59. Cobalt-60 is a commercially important radioisotope, used as a radioactive tracer and for the production of high energy gamma rays.
Monet and the impressionists were among the first to observe that shadows were full of colour. In his "La Gare Saint-Lazare", the grey smoke, vapour and dark shadows are actually composed of mixtures of bright pigment, including cobalt blue, cerulean blue, synthetic ultramarine, emerald green, Guillet green, chrome yellow, vermilion and ecarlate red. Blue was a favourite colour of the impressionist painters, who used it not just to depict nature but to create moods, feelings and atmospheres. Cobalt blue, a pigment of cobalt oxide-aluminium oxide, was a favourite of Auguste Renoir and Vincent van Gogh. It was similar to smalt, a pigment used for centuries to make blue glass, but it was much improved by the French chemist Louis Jacques Thénard, who introduced it in 1802. It was very stable but extremely expensive. Van Gogh wrote to his brother Theo, "'Cobalt [blue] is a divine colour and there is nothing so beautiful for putting atmosphere around things ..."
During the 19th century, a significant part of the world's production of cobalt blue (a dye made with cobalt compounds and alumina) and smalt (cobalt glass powdered for use for pigment purposes in ceramics and painting) was carried out at the Norwegian Blaafarveværket. The first mines for the production of smalt in the 16th century were located in Norway, Sweden, Saxony and Hungary. With the discovery of cobalt ore in New Caledonia in 1864, the mining of cobalt in Europe declined. With the discovery of ore deposits in Ontario, Canada in 1904 and the discovery of even larger deposits in the Katanga Province in the Congo in 1914, the mining operations shifted again. When the Shaba conflict started in 1978, the copper mines of Katanga Province nearly stopped production. The impact on the world cobalt economy from this conflict was smaller than expected: cobalt is a rare metal, the pigment is highly toxic, and the industry had already established effective ways for recycling cobalt materials. In some cases, industry was able to change to cobalt-free alternatives.
Blue and white porcelain artifacts decorating white porcelain with paintings and designs in underglaze by using natural cobalt pigment are another example of popular wares of the Joseon period. Many of these items were created by court painters employed by the royal family. During this period, the popular style of landscape paintings is mirrored in the decoration of ceramics. Initially developed by the Chinese at the Jingdezhen kilns in the mid-14th century, Joseon began to produce this type of porcelain from the 15th century under Chinese influence. The first cobalt imported from China was used by Korean artists. In 1463 when sources of cobalt were discovered in Korea, artists and their buyers found the material was inferior in quality and preferred the more expensive imported cobalt. Korean porcelain with imported cobalt decoration contradict the emphasis of an orderly, frugal and moderate life in Neo-Confucianism.
Many vivid synthetic pigments became commercially available to artists for the first time during the 19th century. These included cobalt blue, viridian, cadmium yellow, and synthetic ultramarine blue, all of which were in use by the 1840s, before Impressionism. The Impressionists' manner of painting made bold use of these pigments, and of even newer colours such as cerulean blue, which became commercially available to artists in the 1860s.
Cobalt(II) oxide has for centuries used as a coloring agent on kiln fired pottery. The additive provides a deep shade of blue named cobalt blue. The band gap (CoO) is around 2.4 eV.
It also is used in cobalt blue glass.
It is particularly valuable for artistic painting of skies because of its hue, its permanence, and its opaqueness. Berthe Morisot painted the blue coat of the woman in her "Summer's Day", 1879 in cerulean blue in conjunction with artificial ultramarine and cobalt blue.
Today, cobalt chromate is sometimes marketed under the cerulean blue name but is darker and greener (Rex Art colour index PB 36) than the cobalt stannate version (colour index PB 35). The chromate makes excellent turquoise colours and is identified by Rex Art and some other manufacturers as "cobalt turquoise".
The blue pigment was derived from cobalt oxide, which had been imported sporadically from Persia in earlier periods. From the 14th century regular imports of the pigment were obtained from Persia. The cobalt was ground and mixed with a medium, then painted onto the dried bodies of the pots, which were then glazed and fired. At a later date a source of cobalt was found within China; this differed from the Persian ore in the proportion of associated manganese. The colour on the fired pots was a grey-blue rather than a pure blue. By mixing three parts Persian ore to two parts Chinese a rich and soft blue was produced, which became labelled as 'Sumatran' or 'Muhammadan' blue.
Before the 19th century, cobalt was predominantly used as a pigment. It has been used since the Middle Ages to make smalt, a blue-colored glass. Smalt is produced by melting a mixture of roasted mineral smaltite, quartz and potassium carbonate, which yields a dark blue silicate glass, which is finely ground after the production. Smalt was widely used to color glass and as pigment for paintings. In 1780, Sven Rinman discovered cobalt green, and in 1802 Louis Jacques Thénard discovered cobalt blue. Cobalt pigments such as cobalt blue (cobalt aluminate), cerulean blue (cobalt(II) stannate), various hues of cobalt green (a mixture of cobalt(II) oxide and zinc oxide), and cobalt violet (cobalt phosphate) are used as artist's pigments because of their superior chromatic stability. Aureolin (cobalt yellow) is now largely replaced by more lightfast yellow pigments.
Blue pigments were made from minerals, especially lapis lazuli and azurite (. These minerals were crushed, ground into powder, and then mixed with a quick-drying binding agent, such as egg yolk (tempera painting); or with a slow-drying oil, such as linseed oil, for oil painting. To make blue stained glass, cobalt blue (cobalt(II) aluminate: )pigment was mixed with the glass. Other common blue pigments made from minerals are ultramarine (), cerulean blue (primarily cobalt (II) stanate: ), and Prussian blue (milori blue: primarily ).
The first cobalt violet, the intensely red-violet cobalt arsenate, was highly toxic. Although it persisted in some paint lines into the twentieth-century, it was displaced by less toxic cobalt compounds such as cobalt phosphate. Cobalt violet appeared in the second half of the 19th century, broadening the palette of artists. Cobalt violet was used by Paul Signac (1863–1935), Claude Monet (1840–1926), and Georges Seurat (1859–1891). Today, cobalt ammonium phosphate, cobalt lithium phosphate, and cobalt phosphate are available for use by artists. Cobalt ammonium phosphate is the most reddish of the three. Cobalt phosphate is available in two varieties — a deep less saturated blueish type and a lighter and brighter somewhat more reddish type. Cobalt lithium phosphate is a saturated lighter-valued bluish violet. A color similar to cobalt ammonium phosphate, cobalt magnesium borate, was introduced in the later twentieth-century but was not deemed sufficiently lightfast for artistic use. Cobalt violet is the only truly lightfast violet pigment with relatively strong color saturation. All other light-stable violet pigments are dull by comparison. However, the high price of the pigment and the toxicity of cobalt has limited its use.
Examples of oxides that do not lose their colour during a glost firing are the cobalt blue made famous by Chinese Ming dynasty blue and white porcelain and the cobalt and turquoise blues, pale purple, sage green, and bole red characteristic of İznik pottery. The painting styles used are covered at (among other articles): china painting, blue and white pottery, tin-glazed pottery, maiolica, Egyptian faience, Delftware. In modern times a wider range of underglaze colours are available.
Several car manufacturers including Jeep and Bugatti have cobalt blue as paint options.
During the late 18th century Richard Champion, a Bristol merchant and potter, making porcelain, was working with a chemist, William Cookworthy. Cookworthy began a search for good quality cobalt oxide to give the blue glaze decoration on the white porcelain and obtained exclusive import rights to all the cobalt oxide from the Royal Saxon Cobalt Works in Saxony. It is uncertain when Bristol blue glass was first made but the quality and beauty of the glass swiftly gained popularity, with seventeen glass houses being set up in the city.
Cobalt blue is a blue pigment made by sintering cobalt(II) oxide with 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 has historically 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.
Cobalt blue is toxic when inhaled or ingested. Potters who fail to take adequate precautions when using cobalt blue may succumb to cobalt poisoning.
There are economic and strategic incentives to bring more security to the Congo, which is rich in natural resources such as cobalt, a strategic and critical metal used in many industrial and military applications. The largest use of cobalt is in superalloys, used to make jet engine parts. Cobalt is also used in magnetic alloys and in cutting and wear-resistant materials such as cemented carbides. The chemical industry consumes significant quantities of cobalt in a variety of applications including catalysts for petroleum and chemical processing; drying agents for paints and inks; ground coats for porcelain enamels; decolourisers for ceramics and glass; and pigments for ceramics, paints, and plastics. The country contains 80% of the world's cobalt reserves.
Moderately ground cobalt glass (potassium cobalt silicate)—called "smalt"—has been historically important as a pigment in glassmaking, painting, pottery, for surface decoration of other types of glass and ceramics, and other media. Cobalt aluminate, also known as "cobalt blue", can be used in a similar way.
The introduction of oil painting changed the way colours looked and how they were used. Ultramarine pigment, for instance, was much darker when used in oil painting than when used in tempera painting, in frescoes. To balance their colours, Renaissance artists like Raphael added white to lighten the ultramarine. The sombre dark blue robe of the Virgin Mary became a brilliant sky blue. Titian created his rich blues by using many thin glazes of paint of different blues and violets which allowed the light to pass through, which made a complex and luminous colour, like stained glass. He also used layers of finely ground or coarsely ground ultramarine, which gave subtle variations to the blue.
In about the 9th century, Chinese artisans abandoned the Han blue colour they had used for centuries, and began to use cobalt blue, made with cobalt salts of alumina, to manufacture fine blue and white porcelain, The plates and vases were shaped, dried, the paint applied with a brush, covered with a clear glaze, then fired at a high temperature. Beginning in the 14th century, this type of porcelain was exported in large quantity to Europe where it inspired a whole style of art, called Chinoiserie. European courts tried for many years to imitate Chinese blue and white porcelain, but only succeeded in the 18th century after a missionary brought the secret back from China.
Cobalt has been used to color glass since the Bronze Age. The excavation of the Uluburun shipwreck yielded an ingot of blue glass, cast during the 14th century BC. Blue glass from Egypt was either colored with copper, iron, or cobalt. The oldest cobalt-colored glass is from the eighteenth dynasty of Egypt (1550–1292 BC). The source for the cobalt the Egyptians used is not known.