The Cyanotype
technique

The cyanotype process was one of the first non-silver techniques used to create photographic images. The technique was invented in 1842 by the English scientist and astronomer John Frederick William Herschel. It was not utilized in mainstream photography and was adopted as a copy technique, becoming known by the term "blueprint", with its blue background reproductions of large architectural and mechanical drawings. It was also used by the English botanist Anna Atkins to create a series of cyanotype limited-edition books that documented ferns and other plant life.