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Cobalt blue
From Wikipedia, the free encyclopedia
(Redirected from Cobalt (color))
| Cobalt | ||
|---|---|---|
 |
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| 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]
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- 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.
- Because of its chemical stability in the presence of alkali, cobalt blue is used as a pigment in blue concrete.
- The blue seen on many glassware pieces is cobalt blue, and it is used widely by artists in many other fields.
- "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.
 An example of the hue of cobalt blue. |
 The color is due to cobalt ions in the glass. |
- ^ 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
- History of Cobalt blue. Pigments through the Ages. WebExhibits.
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