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Cobalt blue



Cobalt
— Colour coordinates —
Hex triplet #0047AB
RGBB (r, g, b) (0, 71, 171)
HSV (h, s, v) (215°, 100%, 67%)
Source BF2S Color Guide
B: Normalized to [0–255] (byte)

Cobalt is a cool, slightly desaturated blue colour, historically made using cobalt salts. It was discovered by Louis-Jacques Thenard in 1802[citation needed]. The world leading manufacturer of cobalt blue in the 19th century was Blaafarveværket in Norway, led by Benjamin Wegner. It is extraordinarily stable. Chemically it is a cobalt(II) oxide-aluminium oxide, or cobalt(II) aluminate, CoAl2O4. Commercial production began in France in 1807. It is made by sintering the stoichiometric mixture of finely ground CoO and Al2O3 at 1200°C.

Additional recommended knowledge

The first recorded use of cobalt blue as a color name in English was in 1777. [1]

Cobalt blue in human culture

Art

  • John Varley suggested cobalt blue as a good substitution for ultramarine blue for painting skies.
  • Maxfield Parrish, famous partly for the intensity of his skyscapes, used cobalt blue, and cobalt blue is sometimes called Parrish blue as a result.

Construction

  • Because of its chemical stability in the presence of alkali, cobalt blue is used as a pigment in blue concrete.

Glassmaking

  • The blue seen on many glassware pieces is cobalt blue, and it is used widely by artists in many other fields.

Ophthalmology

  • "Cobalt Blue" is used a filter used in ophthalmoscopes, and is used to illuminate the cornea of the eye following application of fluorescein dye which is used to detect corneal ulcers and scratches.

References

  1. ^ Maerz and Paul A Dictionary of Color New York:1930 McGraw-Hill Page 91; Color Sample of Cobalt Blue: Page 131 Plate 34 Color Sample L7

See also

  • List of colours
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Cobalt_blue". A list of authors is available in Wikipedia.
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