[REPUBLISHED Originally Posted April 21 2006] The Cyanotype process has been around since at least 1842. The invention of the process is credited to Sir John Herschel. The images it creates are based on ferric salts that create the distinctive prussian blue tone that this process is so known for. There are numerous websites and books that outline various recipes or how-to’s on creating Cyanotypes. This how-to is mine. This will show you step by step how to make a cyanotype print.