Cyanotype is an early photographic technique, invented in 1842. The process uses two chemicals: ferric ammonium citrate and potassium ferricyanide which is painted on to a surface to create light sensitive paper. Objects or homemade negatives are placed over the paper and exposed to the UV rays of the sun. After a few minutes exposure the chemicals are washed off in water to reveal the blue coloured image.
Tea Bag Cyanotypes