Sunprints are cyanotypes which are produced by exposing light sensitive paper to ultraviolet light such as that produced by the sun. Sunprints are merely one among many photographic printing processes, and the concept is very old, since only the most basic of equipment is required to make a Sunprint. Some professional photographers create cyanotypes in the course of their work, and they also make a popular classroom activity to get children thinking about photography and the arts.
Although the concept of the cyanotype is quite old, Sunprints were actually developed by the University of California, Berkeley’s Lawrence Hall of Science, which sells them in kit form for people who want to explore the art. Sunprint kits contain sheets of paper which have been covered in a solution of ammonium iron(III) citrate and potassium ferricyanide. When these chemicals are exposed to sunlight, they react, forming ferric ferrocyanide, also known as Prussian Blue, a brilliant blue dye which cannot be washed out. The kits typically also contain a clipboard for stabilizing the paper on, along with plexiglass to help keep objects in place as a Sunprint is made.
Obviously, simply exposing a sheet of Sunprint paper to sunlight wouldn’t make a very interesting image, as the entire print would turn a uniform shade of blue. To make Sunprints, people place various objects between the paper and the source of light, ranging from car keys to leaves. Many people like to make Sunprints of natural items such as leaves and feathers, but any sort of roughly flat item, including one’s hand, will do. The paper typically starts out with a faint bluish tint, turning white as it is exposed to UV light. When the exposure is finished, the paper is rinsed in water, and a print will slowly emerge.
Some photographs make Sunprints of transparencies of other work, such as photographs taken with film, especially if they shoot in black and white. The rich blue color of a cyanotype can transform a transparency into a haunting and unusual image. Others experiment with exposures of an assortment of items, and some people like to move objects around to create nuances of shading and a sense of movement. This very basic printing process can be utilized in a wide range of ways.
If you want to make Sunprints on your own, you should be able to find a Sunprint kit at a science store, museum shop, or children’s store in your area. Numerous companies make variations on the official Sunprint kit which may have names like “Solargraphics” and “Sun Exposures.” The process of making Sunprints is very fun, and safe for artists of all ages.