Blue hair

Blue hair is a type of hair color that does not naturally occur in human hair pigmentation, although the hair of some animals (such as dog coats) is described as blue. Some humans are born with bluish-black hair (also known as "blue black" hair), which is black that has a blue hue under the light.

The color has a long history of artistic and literary uses.

The 18th century English politician, Charles Fox, was a fashionable macaroni in his youth and tinted his hair with blue powder.

In 1913–1914, just before World War I, there was a vogue for dyed brightly coloured hair in exotic shades such as blue, violet or emerald. This started in Paris and then spread to other cities such as London. In 1924, the first celebrity hairdresser, Monsieur Antoine, dyed his dog's hair blue. An influential client, Lady Elsie De Wolfe Mendl, took up the same style and this started a new fad. Later in the 20th century, mature ladies had a blue rinse to conceal grey hair. The Queen Mother was the trend-setter and the peak of popularity for this fashion was the period following the Second World War.

In the 2007 autumn fashion season, designers such as Marc Jacobs and Duckie Brown dyed the hair of their models blue to give them a shocking punk look. In 2011, the blue rinse became fashionable again and exemplars included Kate Bosworth with a dip-dyed style of turquoise tips while Thakoon Panichgul continued to present models with startling, all-blue hair.

A synthetic dye used to colour hair blue was 1,4,5,8-tetraaminoanthraquinone prepared as Disperse Blue 1 with water and lignosuphonate dispersant. This is a semi-permanent dye as the dye molecules do not penetrate the hair shaft and so wash out in subsequent shampooing. It is no longer used in the USA as it is thought to be carcinogenic.

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