Here is a link to a Flikr gallery that contains samples of my Cyanotypes and Anthrotypes.
The Cyanotype process was invented in 1842 by Sir John Herschel, an English astronomer and scientist. The process of cyanotype printing makes use of two chemicals. These are Potassium ferricyanide and Ammonium iron (III) citrate. Commonly a contact print is made by exposing in the sun. Exposed areas turn a beautiful Prussian blue due to a chemical reaction in the iron caused by UV light.
Just as in the gum bichromate process, several coatings may be applied to the print, which I have done using coatings with varied amounts of activator or freshness. Additionally some images have been soaked or bleached in tea or coffee and a various combinations of all the above. Cyanotypes are considered to be more or less permanent, but it is not recommended to keep them in bright sunlight. If the image does fade it is recommended to store them in a dark place for a time and the image will be restored.