Cobalt blue

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Cobalt
— Colour coordinates —
Hex triplet		#0047AB
RGB^B	(r, g, b)	(0, 71, 171)
HSV	(h, s, v)	(215°, 100%, 67%)
Source		^[Unsourced]
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. 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 aluminate. Commercial production began in France in 1807.

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

"Cobalt Blue" is also 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.

An example of the hue of cobalt blue.

[edit] See also

List of colours

[edit] External links

History of Cobalt blue

					Shades of blue
Alice blue	Azure	Baby blue	Blue	Cerulean	Cerulean blue	Cobalt blue	Cornflower blue	Dark blue	Denim	Dodger blue	Indigo

International Klein Blue	Light blue	Midnight Blue	Navy blue	Periwinkle	Persian blue	Powder blue	Prussian blue	Royal blue	Sapphire	Steel blue	Ultramarine