CYANOTYPE is one of the first photographic printing processes developed by English scientist and astronomer Sir John Herschel in 1842.
An object is placed on a reactive surface and developing in UV light creates a cyan blue silhouette. The process was used to create low cost copies of drawings and plans by Engineers well into the 20th century. The monochrome photographic printing process which gives a cyan-blue print process uses two chemicals: ferric ammonium citrate and potassium ferricyanide. The image is applied to any natural surface such as paper, wood, silk and cotton and the process is relatively simple. I liked the results because no print is the same. The result is always a surprise.