The history of the cyanotype process is a very old one. An English scientist, Sir John Herschel, discovered the procedure in 1842. An iron-based rather than silver-based photographic process, Herschel used it to reproduce diagrams (as in “blueprints”). Often recognized as the first female photographer, it was an English woman, Anna Atkins (1799 – 1871), who brought the process to photography. Anna, a botanist, documented plant life with her cyanotypes.
How does the process work? Two chemicals, ferric ammonium citrate and potassium ferricyanide, are used to sensitize paper. Most of the images I use for cyanotypes come from my own photos and those of my father. The challenge was to figure out how to translate the cyanotype process to fabric so I could integrate my images into my fiber work. I use silk, which after exposure to the chemicals, is allowed to dry overnight and is then packed into a photographic bag to protect it from exposure to light until I'm ready to make prints. I make negatives of these images on my computer and then print on silk outdoors in my dyer's garden, using the light of the sun.