Here is one of my cyanotype prints I produced a few years ago at a workshop.
According to Wilkipedia, a Cyanotype is a photographic printing process that produces a cyan-blue print. Engineers used the process well into the 20th century as a simple and low-cost process to produce copies of drawings, referred to as blueprints. The process uses two chemicals: ammonium iron(III) citrate and potassium ferricyanide.
Stockport In Print 