Cerulean (), also spelled caerulean, is a shade of blue ranging between

azure Azure may refer to: Colour * Azure (color), a hue of blue ** Azure (heraldry) ** Shades of azure, shades and variations Arts and media * ''Azure'' (Art Farmer and Fritz Pauer album), 1987 * Azure (Gary Peacock and Marilyn Crispell album), 2013 ...

and a darker sky blue. The first recorded use of ''cerulean'' as a colour name in English was in 1590. The word is derived from the Latin word '' caeruleus'', "dark blue, blue, or blue-green", which in turn probably derives from ''caerulum'', diminutive of ''caelum'', "heaven, sky". "Cerulean blue" is the name of a pigment. The pigment was discovered in the late eighteenth century and designated as cerulean blue in the nineteenth century.

Cerulean blue pigment

The primary chemical constituent of the pigment is cobalt(II) stannate (). The precise hue of the pigment is dependent on a variable silicate component. The pigment Cerulean blue was discovered in 1789 by the Swiss chemist Albrecht Höpfner. Subsequently, there was a limited German production under the name of ''Cölinblau''. It was in 1860 first marketed in the United Kingdom by colourman George Rowney, as "coeruleum". Other nineteenth century English pigment names included "ceruleum blue" and "corruleum blue". When the cerulean blue pigment (see the adjacent colour box) was discovered, it became a useful addition to

Prussian blue Prussian blue (also known as Berlin blue, Brandenburg blue or, in painting, Parisian or Paris blue) is a dark blue pigment produced by oxidation of ferrous ferrocyanide salts. It has the chemical formula Fe CN)">Cyanide.html" ;"title="e(Cyanid ...

cobalt blue Cobalt blue is a blue pigment made by sintering cobalt(II) oxide with aluminum(III) oxide (alumina) at 1200 °C. Chemically, cobalt blue pigment is cobalt(II) oxide-aluminium oxide, or cobalt(II) aluminate, CoAl2O4. Cobalt blue is lighter ...

, and synthetic ultramarine, which already had superseded the prior blue and blue‑ish pigments. The pigment is very expensive. ''Pigments through the ages'' shows a "Painted swatch of cerulean blue" to represent the actual cobalt stannate pigment. See also painted swatch and crystals of cerulean blue at ColourLex. It is particularly valuable for artistic painting of skies because of its hue, its permanence, and its opaqueness.

Berthe Morisot Berthe Marie Pauline Morisot (; January 14, 1841 – March 2, 1895) was a French painter and a member of the circle of painters in Paris who became known as the Impressionists. In 1864, Morisot exhibited for the first time in the highly es ...

painted the blue coat of the woman in her ''

Summer's Day ''Summer's Day'' (or ''Jour d'eté'') is an oil on canvas painting by the French Impressionist painter Berthe Morisot, created in 1879. The painting depicts two women seated in a row boat, and was painted in the Bois de Boulogne. It is held at the ...

'', 1879 in cerulean blue in conjunction with artificial ultramarine and

. Today, cobalt chromate is sometimes marketed under the cerulean blue name but is darker and greener than the cobalt stannate version. The chromate makes excellent turquoise colours and is identified by ''Rex Art'' and some other manufacturers as "cobalt turquoise". File:PB35 Bleu Céruléum.JPG, Cerulean blue PB35 File:Berthe Morisot - Sommertag - 1879.jpeg,

, ''

'', (1879) Image:Cerulean blue hue.png, A sample swatch of cerulean blue hue oil paint. " Hue" in this instance means that other pigments have been used to mimic the color of oil paint that contains the original pigment. File:Ceruleum.png, Cerulean blue pigment in oil. On the left as a standoil glaze over zinc white; on the right as a mass tone in oil-based paint.

Other colour variations

Pale cerulean

Pantone, in a press release, declared the pale hue of cerulean at right, which they call ''cerulean'', as the "colour of the millennium". The source of this colour is the " Pantone Textile Paper eXtended (TPX)" colour list, colour #15-4020 TPX—Cerulean.

Cerulean (Crayola)

This bright tone of cerulean is the colour called ''cerulean'' by Crayola crayons.

Cerulean frost

At right is displayed the colour cerulean frost. ''Cerulean frost'' is one of the colours in the special set of metallic coloured Crayola crayons called Silver Swirls, the colours of which were formulated by Crayola in 1990.

Curious Blue

Curious Blue is one of the bright tone colors of cerulean

In nature

* Cerulean cuckooshrike * Cerulean kingfisher * Cerulean flycatcher * Cerulean warbler * Cerulean-capped manakin

Explanatory notes

References

External links

A page on Cerulean BlueCerulean blue
at ColourLex {{Color topics Quaternary colors Pigments Inorganic pigments Shades of azure Shades of blue Shades of cyan Bird colours Cobalt compounds