The Cyanotype Process

The cyanotype (Ferro-Prussiate) is often the first process you will encounter in alternative/nonsilver photography. The reason for this is the absolute simplicity of the nearly fail-safe technique and chemistry and the likelihood that you will make a successful print within a short time. Discovered by Sir John Herschel (1792–1871) in 1842, a mere three years after the “official” announcement of the discovery of photography, the cyanotype provided permanent images in an elegant assortment of blue values. Herschel is the same gentleman who coined the words positive and negative, photograph, and snapshot. He is also credited, in 1819, with discovering that a solution of sodium thiosulfate (which he referred to as hyposulfite of soda) had the ability to dissolve silver chloride and what that particular chemical’s role might be in permanently fixing a photographic image. This is an important bit of information that he passed along to Talbot. Curiously, Herschel did not officially announce this particular finding until 1839.

by:Christopher James