Cyanography is an artistic practice that utilises a particular type of photographic reproduction – the cyanotype. Invented in 1842 by Sir John Herschel, this process requires a material, commonly fabric or paper, to be coated in photosensitive solution – usually a combination of ferric ammonium citrate and potassium ferricyanide. This results in blue mono-tonal reproductions of the photographic negative, commonly called a blueprint.