Aureolin (sometimes called Cobalt Yellow) is a pigment sparingly used in oil and watercolor painting. Its color index name is PY40 (40th entry on list of yellow pigments). It was first made in 1848 by Nikolaus Wolfgang Fischer in Breslau[1] and its chemical composition is potassium cobaltinitrite. The investigation by Gates gives the exact modern procedures for the preparation of aureolin and also the methods for its identification in paintings.[2][3]

Aureolin is rated as permanent in some reports but there are other sources which rate it as unstable in oils but pronounce it stable in watercolors.[4] Others find it unstable in watercolors, fading to greyish or brownish hues.[5] It is a transparent, lightly staining, light valued, intense medium yellow pigment.

It is a rather expensive pigment and sold by several manufacturers of oil paints such as Grumbacher, Michael Harding, and Holbein. However, the pigment was never popular as an oil color and is much more widely available as a watercolor from manufacturers such as: Winsor & Newton, Talens Rembrandt, Rowney Artists, Sennelier, Art Spectrum and Daniel Smith.[2][3]

    Color coordinates
Hex triplet#FDEE00
sRGBB  (rgb)(253, 238, 0)
HSV       (h, s, v)(56°, 100%, 99%)
B: Normalized to [0–255] (byte)

See also


  1. ^ Fischer, N. W. (1848). "Ueber die salpetrichtsauren Salze". Annalen der Physik und Chemie. 150 (5): 115–125. Bibcode:1848AnP...150..115F. doi:10.1002/andp.18491500512.
  2. ^ a b Gates, G. (1995). "A Note on the Artists' Pigment Aureolin". Studies in Conservation. 40 (3): 201–206. doi:10.2307/1506479. JSTOR 1506479.
  3. ^ a b Gettens, Rutherford John; Stout, George Leslie (1966). Painting materials: A short encyclopaedia. pp. 109–110. ISBN 978-0-486-21597-6.
  4. ^ Cornman, M., Cobalt Yellow (Aureolin), in Artists’ Pigments. A Handbook of Their History and Characteristics, Vol. 1: Feller, R.L. (Ed.) Oxford University Press 1986, p. 37-46
  5. ^ [Pigments: aureolin |]
Ardingly College

Ardingly College is a selective co-educational boarding and day independent school near Ardingly, West Sussex, England. The school is a member of the Headmasters' and Headmistresses' Conference and of the Woodard Corporation of independent schools and as such has a strong Anglo-Catholic tradition. It was originally a boarding school for boys, and became fully co-educational in 1982. For the academic year 2015/16, Ardingly charged day pupils up to £7,710 per term, making it the 29th most expensive Headmasters' and Headmistresses' Conference (HMC) day school. It is a public school in the British sense of the term (i.e. fee-paying). As of 2017, there are about 416 pupils enrolled at the school, aged between 13 and 18. Additionally, there are about 520 pupils aged from 2½ to 13 at the Ardingly College Preparatory school, whom it shares some common grounds with.The school is regularly positioned amongst the top ten International Baccalaureate (IB) schools in the United Kingdom, and has won the Royal Society of Chemistry Top of the Bench Competition.Ardingly played an important role in providing infantry throughout the 20th Century conflicts, with around 1,200 Ardingly pupils going on to fight in the First World War, 146 of whom were killed, along with two former members of staff. In addition, 88 Old Ardinians died in World War II; their names being recorded in a book of remembrance.The school's former pupils – or "Old Ardinians" – include four Conservative MP's; actor Terry-Thomas; Formula One World Champion Mike Hawthorn; author Neil Gaiman; Interscan inventor John Paul Wild; and Allard Motor Company founder Sydney Allard.


Cobalt is a chemical element with symbol Co and atomic number 27. Like nickel, cobalt is found in the Earth's crust only in chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal.

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.

Today, some cobalt is produced specifically from one of a number of metallic-lustered ores, such as for example cobaltite (CoAsS). The element is however more usually produced as a by-product of copper and nickel mining. The copper belt in the Democratic Republic of the Congo (DRC) and Zambia yields most of the global cobalt production. The DRC alone accounted for more than 50% of world production in 2016 (123,000 tonnes), according to Natural Resources Canada.Cobalt is primarily used in the manufacture of magnetic, wear-resistant and high-strength alloys. The compounds cobalt silicate and cobalt(II) aluminate (CoAl2O4, 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.

Cobalt is the active center of a group of coenzymes called cobalamins. vitamin B12, the best-known example of the type, is an essential vitamin for all animals. Cobalt in inorganic form is also a micronutrient for bacteria, algae, and fungi.

John Reinhard Weguelin

John Reinhard Weguelin (23 June 1849 – 28 April 1927) was an English painter and illustrator, active from 1877 to after 1910. He specialized in figurative paintings with lush backgrounds, typically landscapes or garden scenes. Weguelin emulated the neo-classical style of Edward Poynter and Lawrence Alma-Tadema, painting subjects inspired by classical antiquity and mythology. He depicted scenes of everyday life in ancient Greece and Rome, as well as mythological subjects, with an emphasis on pastoral scenes. Weguelin also drew on folklore for inspiration, and painted numerous images of nymphs and mermaids. His subjects were similar to those of his contemporary, John William Waterhouse, who also specialized in painting the female figure against dramatic backgrounds, but unlike Waterhouse, many of Weguelin's subjects are nude or scantily-clad. Weguelin was particularly noted for his realistic use of light.

Although his earliest work was in watercolour, all of Weguelin's important works from 1878 to 1892 were oil paintings. In order to supplement his income, he drew and painted illustrations for several books, most famously Macaulay's Lays of Ancient Rome. Beginning in 1893, Weguelin devoted himself almost entirely to watercolour, and became a member of the Royal Watercolour Society.

Weguelin's work was exhibited at the Royal Academy and a number of other important London galleries, and was highly regarded during his career. However, he was forgotten following the first World War, as his style of painting fell out of fashion, and he is best remembered as the painter of Lesbia, depicting the fabled muse of the Roman poet Catullus.

List of Teekyu episodes

Teekyu is an anime series directed and written by Shin Itagaki, based upon a manga distributed in Earth Star Entertainment's Comic Earth Star. The anime has had eight seasons, starting in October 2012. The adaptation was announced alongside the release of the manga's first tankōbon, five months after the manga was first published. This is the fastest manga-release-to-anime-announcement time that Earth Star Entertainment has ever had.The first three seasons are animated by MAPPA. The series' first season aired between October 7 and December 23, 2012, the second one between July 7 and September 22, 2013, and the third one between October 6 and December 22, 2013. The fourth and fifth seasons, along with spinoff Takamiya Nasuno Desu! ("I am Nasuno Takamiya"), are produced by Millepensee. The fourth season and spinoff both aired from April 6 to June 22, 2015. The fifth season of Teekyu aired from July 6, 2015 to September 21, 2015. The sixth season aired from October 5, 2015 to December 21, 2015. The anime has been renewed for a 7th season in January 2016. Season 8 of Teekyū ran from on October 5, 2016 to December 21, 2016. A 9th season has been announced and aired from July to September 2017.

All seasons aired on Tokyo MX and AT-X with the third and later seasons also airing on Sun Television and the first one streamed on Niconico. All seasons have also been simulcasted by Crunchyroll. The first season was released on Blu-ray Disc and DVD on February 22, 2013. The second and third seasons were released on Blu-ray Disc on October 25, 2013, and January 24, 2014, respectively, along with two OVA episodes each. The fourth season and the Takamiya Nasuno Desu! spinoff were released on Blu-ray Disc on August 28, 2015, with the fifth season released on Blu-Ray disc on November 27, 2015.

List of colors (compact)

The following list shows a compact version of the colors in the List of colors A–F, G–M, and N–Z articles. The list shows the color and its name. Hovering over the color box shows the HSV, RGB, and #hex values for the color in the tool tip.

There are 11 main colors. The main 11 colors are red, orange, yellow, green, blue, purple, pink, brown, gray, black and white. The rest of the colors on this list are just different types, combinations and shades of the main 11 colors.

List of inorganic pigments

The following list includes commercially or artistically important inorganic pigments of natural and synthetic origin.

List of post-nominal letters (Brunei)

Brunei has a range of post-nominal letters denoting honours awarded to distinguished citizens.

Nikolaus Wolfgang Fischer

Nikolaus Wolfgang Fischer (15 January 1782 – 19 August 1850) was a German chemist. He first sythezized the Potassium cobaltinitritelater used as Aureolin pigment.


A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which a material emits light. Most materials selectively absorb certain wavelengths of light. Materials that humans have chosen and developed for use as pigments usually have special properties that make them useful for coloring other materials. A pigment must have a high tinting strength relative to the materials it colors. It must be stable in solid form at ambient temperatures.

For industrial applications, as well as in the arts, permanence and stability are desirable properties. Pigments that are not permanent are called fugitive. Fugitive pigments fade over time, or with exposure to light, while some eventually blacken. Pigments are used for coloring paint, ink, plastic, fabric, cosmetics, food, and other materials. Most pigments used in manufacturing and the visual arts are dry colorants, usually ground into a fine powder. For use in paint, this powder is added to a binder (or vehicle), a relatively neutral or colorless material that suspends the pigment and gives the paint its adhesion. A distinction is usually made between a pigment, which is insoluble in its vehicle (resulting in a suspension), and a dye, which either is itself a liquid or is soluble in its vehicle (resulting in a solution). A colorant can act as either a pigment or a dye depending on the vehicle involved. In some cases, a pigment can be manufactured from a dye by precipitating a soluble dye with a metallic salt. The resulting pigment is called a lake pigment. The term biological pigment is used for all colored substances independent of their solubility.In 2006, around 7.4 million tons of inorganic, organic and special pigments were marketed worldwide. Asia has the highest rate on a quantity basis followed by Europe and North America. The global demand on pigments was roughly US$20.5 billion in 2009.


Potassium is a chemical element with symbol K (from Neo-Latin kalium) and atomic number 19. It was first isolated from potash, the ashes of plants, from which its name derives. In the periodic table, potassium is one of the alkali metals. All of the alkali metals have a single valence electron in the outer electron shell, which is easily removed to create an ion with a positive charge – a cation, which combines with anions to form salts. Potassium in nature occurs only in ionic salts. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and reacts vigorously with water, generating sufficient heat to ignite hydrogen emitted in the reaction, and burning with a lilac-colored flame. It is found dissolved in sea water (which is 0.04% potassium by weight), and is part of many minerals.

Potassium is chemically very similar to sodium, the previous element in group 1 of the periodic table. They have a similar first ionization energy, which allows for each atom to give up its sole outer electron. That they are different elements that combine with the same anions to make similar salts was suspected in 1702, and was proven in 1807 using electrolysis. Naturally occurring potassium is composed of three isotopes, of which 40K is radioactive. Traces of 40K are found in all potassium, and it is the most common radioisotope in the human body.

Potassium ions are vital for the functioning of all living cells. The transfer of potassium ions through nerve cell membranes is necessary for normal nerve transmission; potassium deficiency and excess can each result in numerous signs and symptoms, including an abnormal heart rhythm and various electrocardiographic abnormalities. Fresh fruits and vegetables are good dietary sources of potassium. The body responds to the influx of dietary potassium, which raises serum potassium levels, with a shift of potassium from outside to inside cells and an increase in potassium excretion by the kidneys.

Most industrial applications of potassium exploit the high solubility in water of potassium compounds, such as potassium soaps. Heavy crop production rapidly depletes the soil of potassium, and this can be remedied with agricultural fertilizers containing potassium, accounting for 95% of global potassium chemical production.

Potassium cobaltinitrite

Potassium cobaltinitrite, IUPAC name potassium hexanitritocobaltate(III), is a salt with the formula K3[Co(NO2)6]. It is a yellow solid that is insoluble in water. The compound finds some use as a yellow pigment.

The salt features potassium cations and an trianionic coordination complex. In the anion, cobalt is bound by six nitrito ligands, the overall complex having octahedral molecular geometry. The oxidation state of cobalt is 3+. Its low-spin d6 configuration confers kinetic stability and diamagnetism.

The compound was first described in 1848 by Nikolaus Wolfgang Fischer in Breslau, and it is used as a yellow pigment called Aureolin.

Samizu Matsuki

Samizu Matsuki (born March 16, 1936 in Uryū, Hokkaidō, Japan – died August 4, 2018 in Rockland, Maine, USA), was a Japanese artist and educator.She won the Gold Medal at the 1970 First New York International Art Show, the Grand Prix at the 1971 Locust Valley Art Show on Long Island, New York, and the Award of Excellence at the Abraham & Straus-Hempstead Art Show, "Long Island Art '74" for her explorations of classical realism. Matsuki was first woman member of the Salmagundi Club.

University of Cape Coast

The University of Cape Coast is a public collegiate research university located in Cape Coast, Ghana. The university was established in 1962 out of a dire need for highly qualified and skilled manpower in education. It was established to train graduate teachers for second cycle institutions such as teacher training colleges and technical institutions, a mission that the two existing public universities at the time were unequipped to fulfill. The university has since added to its functions the training of doctors and health care professionals, as well as education planners, administrators, and agriculturalists. UCC graduates include Ministers of State, High Commissioners, CEOs, and Members of Parliament.

Watercolor painting

Watercolor (American English) or watercolour (British English; see spelling differences), also aquarelle (French, diminutive of Latin aqua "water"), is a painting method in which the paints are made of pigments suspended in a water-based solution. Watercolor refers to both the medium and the resulting artwork. Aquarelles painted with water-soluble colored ink instead of modern water colors are called "aquarellum atramento" (Latin for "aquarelle made with ink") by experts. However, this term has been more and more passing out of use.The traditional and most common support—material to which the paint is applied—for watercolor paintings is paper. Other supports include papyrus, bark papers, plastics, vellum, leather, fabric, wood and canvas. Watercolor paper is often made entirely or partially with cotton. This gives the surface the appropriate texture and minimizes distortion when wet. Watercolors are usually translucent, and appear luminous because the pigments are laid down in a pure form with few fillers obscuring the pigment colors. Watercolors can also be made opaque by adding Chinese white.

In East Asia, watercolor painting with inks is referred to as brush painting or scroll painting. In Chinese, Korean and Japanese painting it has been the dominant medium, often in monochrome black or browns, often using inkstick or other pigments. India, Ethiopia and other countries have long watercolor painting traditions as well.

American artists in the early 19th century seemed to regard watercolor primarily as a sketching tool in preparation for the "finished" work in oil or engraving.

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