dark blue

cyanotypes | Van Dyke brownprints | pinhole cameras

Alternate photography

Cyanotypes

Invented in 1842 by Sir John Henschel, who discovered that combining iron salts (potassium ferricyanide and ferric ammonium citrate) in water created a light-sensitive solution that when applied to paper and exposed to sunlight (ultraviolet light) could produce a fixed image. He called these blue imprints cyanotypes. Henschel is also credited with coining the word "photography" (light drawing).

The process is relatively simple - treated paper is exposed to sunlight with the subject to be imprinted placed on top of the paper (usually pressed between sheets of glass to keep the subject in position). The exposed paper is then rinsed with water, which initiates the chemical reaction and develops the image.

Back to main site index