Cyanotype

A short history of the Cyanotype
Cyanotype is a photographic process that produces prints or images in a dark blue colour known as Prussian blue. The process takes its name from the Greek 'kyanos' meaning 'dark blue', in reference to this characteristic colour.

This technique is linked to the effect of light on two mixed chemicals: ferric ammonium citrate and potassium ferricyanide. In the presence of light energy, the mixture oxidises in air and takes on a blue colour. This technique was discovered in 1842 by the English astronomer and chemist John Frederick Herschel, during his research into the effects of light.

Today, the cyan blue used by printers is 100% cyan.

Despite the speed and simplicity of this process, the cyanotype was never a real success, but it was used by the botanist Anna Atkins to reproduce tiny plants that were complicated to draw. Her herbarium made up entirely of cyanotype reproductions of algae, 'Photographs of British Algae: Cyanotype impressions', is considered to be the first publication of a photographic work! Only around twenty copies are known to exist in the world, and each print was made by Anna Atkins herself. Nowadays, cyanotype is used mainly for artistic and educational purposes, and some contemporary artists produce beautiful pictorial works using it.