Colour story: cerulean blue

A pure blue pigment, cerulean blue is opaque and bright due to its highly refractive particles. It is stable and does not react to light or chemicals, making it a permanent and invaluable part of the artist’s palette.

For a clue to the origin of the name, you need to look upwards. The word cerulean comes from the Latin caeruleus, meaning dark blue caelum – which in turn probably derives from caelulum, meaning heaven or sky.

After the discovery of cobalt blue by the French chemist Louis Jacques Thénard in 1802, the Swiss chemist Albrecht Höpfner created cerulean blue from cobalt stannate in 1805. It is made by the calcination of tins, salts and silica with cobalt sulphate and is an inorganic synthetic mineral pigment. It took a while for the colour to become widely available to artists – more than 55 years, in fact – and was introduced in the 1860s under the trade name coeruleum.

Cerulean blue was quickly adopted by artists, including the Impressionists, because of its hue, permanence and opaqueness. It was particularly useful for skyscapes and can be found in the sky of Monet’s 1877 La Gare Saint-Lazare, the pointillism of Paul Signac, and in Édouard Manet’s 1878 Corner of a Café-Concert.

The colour has earned widespread popularity. In 1999 it was nominated by Pantone as the colour of the millennium. According to Leatrice Eiseman, executive director of the Pantone Color Institute, “Psychologically, gazing at a blue sky brings a sense of peace and tranquillity to the human spirit. Sky blue is imprinted in our psyches as a retiring, quiescent color. Surrounding yourself with cerulean blue could bring on a certain peace because it reminds you of time spent outdoors, on a beach, near the water – associations with restful, peaceful, relaxing times.”

And in the 2006 film The Devil Wears Prada, cerulean is the shade worn by Anne Hathaway. It becomes the subject of a lecture by her boss, played by Meryl Streep, on the lineage and influence on cerulean in the fashion industry.

“This stuff’?” she says. “Oh, ok. I see, you think this has nothing to do with you. You go to your closet and you select out, oh I don’t know, that lumpy blue sweater, for instance, because you’re trying to tell the world that you take yourself too seriously to care about what you put on your back.

“But what you don’t know is that that sweater is not just blue, it’s not turquoise, it’s not lapis, it’s actually cerulean. You’re also blindly unaware of the fact that in 2002, Oscar de la Renta did a collection of cerulean gowns. And then I think it was Yves St Laurent, wasn’t it, who showed cerulean military jackets? And then cerulean quickly showed up in the collections of eight different designers. Then it filtered down through the department stores and then trickled on down into some tragic ‘casual corner’ where you, no doubt, fished it out of some clearance bin.”

Cerulean blue pigment is an expensive pigment and remains as popular now as it was when it was first introduced.