Cobalt blue

From Wikipedia, the free encyclopedia

Cobalt
<imagemap>Image:Information-silk.png|About these coordinates rect 0 0 50 50 About these coordinates desc none</imagemap>— 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.

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

Contents 1 Cobalt blue in human culture 2 References 3 See also 4 External links

[edit] 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.

Cobalt blue hue.png An example of the hue of cobalt blue.

Bristol.blue.glass.arp.750pix.jpg The color is due to cobalt ions in the glass.

[edit] 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

[edit] See also

• List of colours

[edit] External links

• History of Cobalt blue. Pigments through the Ages. WebExhibits.

v • d • e Shades of blue
Air Force blue	Alice blue	Azure	Baby blue	Blue	Cerulean	Cerulean blue	Cobalt blue	Columbia blue	Cornflower blue	Dark blue
Denim	Dodger blue	Egyptian blue	Electric blue	Han Purple	Indigo	International Klein Blue	Light blue	Maya Blue	Midnight blue	Navy blue
Periwinkle	Persian blue	Powder blue	Prussian blue	Royal blue	Sapphire	Sky blue	Steel blue	Ultramarine

de:Thénards Blau

fa:لاجوردی fr:Bleu de cobalt nl:Kobaltblauw ja:コバルトブルー no:Koboltblå ru:Тенарова синь simple:Cobalt blue sv:Koboltblått vi:Cô ban (màu) zh:鈷藍色