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A brilliant, transparent yellow pigment also known by the name cobalt yellow. Cobalt yellow is composed of potassium cobaltinitrite. It was discovered by N.W. Fischer in Germany in 1848. Cobalt yellow was introduced as an artists' pigment in 1852 (Saint-Evre) and began selling commercially in the U.S. in 1861. Aureolin is a permanent pigment, but may discolor to brown when mixed with indigo in the presence of hydrogen sulfide. Because of its poor hiding power, cobalt yellow is most often used in watercolor and tempera paints, for oil-based glazes and as a colorant in glass.

Synonyms and Related Terms

cobalt yellow; potassium cobaltinitrite; Pigment Yellow 40; CI 77357; Kobaltgelb (Deut.); aureolina (Esp.); jaune de cobalt (Fr.); giallo di cobalto (It.); aureolina (It.); amarillo de cobalto (Esp.)


Aureolin 342.TIF

Raman (MFA)

Aureolin (Forbes MFA 342), collodion slide 785 nm resize.tif








Slide9 FC342.PNG


Ingestion may cause poisoning with decreased blood pressure, headaches, nausea, vomiting and cyanosis.

Physical and Chemical Properties

Slightly soluble in water, ethanol, ether and carbon disulfide. Soluble in acids producing a pink solution. Decomposes in alkalis evolving nitrogen oxide fumes.

Composition K3[Co(NO2)6].3H2O
CAS 13782-01-9
Density 1.8 g/ml
Refractive Index 1.72 - 1.76

Resources and Citations

  • M.Cornman, "Cobalt Yellow", Artists Pigments, Volume 1, R. Feller (ed.), Cambridge University Press; Cambridge, 1986.
  • The Dictionary of Art, Grove's Dictionaries Inc., New York, 1996 Comment: Artists Pigments
  • R. J. Gettens, G.L. Stout, Painting Materials, A Short Encyclopaedia, Dover Publications, New York, 1966
  • Ralph Mayer, A Dictionary of Art Terms and Techniques, Harper and Row Publishers, New York, 1969 (also 1945 printing)
  • Reed Kay, The Painter's Guide To Studio Methods and Materials, Prentice-Hall, Inc., Englewood Cliffs, NJ, 1983
  • Michael McCann, Artist Beware, Watson-Guptill Publications, New York City, 1979
  • Susan E. Schur, Conservation Terminology: A review of Past & Current Nomenclature of Materials, Technology and Conservation, Spring (p.34-39); Summer (p.35-38); Fall (p.25-36), 1985
  • Book and Paper Group, Paper Conservation Catalog, AIC, 1984, 1989