cyanotypes

I first came across cyanotypes a couple of years ago when I was exploring various techniques for encaustic collage. In addition to embedding photographic images and natural materials, I discovered this photographic process that creates Prussian blue monochromatic prints, developed in the mid-19th century that harnesses the power of the sun to make detailed prints from virtually any object that casts a shadow. These images can be imprinted on fabric, water colour paper, wood and then enhanced with paints or left as is with the monochromatic blue /white impressions.

For those who have not heard of cyanotypes, here’s some background (excerpts from wiki) and a few of my samples follow:

An image can be produced by exposing sensitised paper to a source of ultraviolet light (such as sunlight) as a contact print.
After exposure, the paper is developed by washing in cold running water: the water-soluble iron(III) salts are washed away. The parts that were exposed to ultraviolet turn blue as the non-water-soluble Prussian blue pigment remains in the paper. This is what gives the print its typical blue color. The blue color darkens upon drying.
The simplest kind of cyanotype print is a photogram, made by arranging objects on sensitised paper. Fresh or pressed plants are a typical subject but any opaque to translucent object will create an image. A sheet of glass will press flat objects into close contact with the paper, resulting in a sharp image. Otherwise, three-dimensional objects or less than perfectly flat ones will create a more or less blurred image depending on the incidence and breadth of the light source.

(from Greek, “Dark Blue”, + “Impression/Mark”)
Uses two chemicals: – Part A: Potassium Ferricyanide—A red iron salt and Part B: Ferric Ammonium Citrate—A light-sensitive iron salt

Discovered by Sir John Herschel who in 1842 published his investigation of light on iron compounds
Anna Atkins, a friend of the Herschel family, over 1843–61 and with the assistance of Anne Dixon, hand-printed several albums of botanical and textile specimens, especially Photographs of British Algae: Cyanotype Impressions,[9] effectively the world’s first photographically-illustrated books