What’s a Cyanotype??
If you live in the US, chances are you may never have heard of a cyanotype before. There are two likely reasons why: for one, the process was invented by a British scientist; and secondly, he invented it nearly 200 years ago!
That individual was Sir John Frederick William Herschel, and he invented the cyanotype process— a form of alternate photography that creates blue and white image imprints (aka, blueprints)—in 1842. A year later, botanist Anna Atkins famously used the cyanotype process to document algae specimens, becoming the first person to illustrate a book using photographic images.
The Art of “Camera-less” Photography
Often called “camera-less” photographs, cyanotypes are created using a 1:1 ratio of two iron salts: ferric ammonium citrate and potassium ferricyanide. Once these salts are combined, they become reactive to ultraviolet (UV) light. A solution of these iron salts is made, and a coating of it is applied to paper. Objects are then placed onto the paper and exposed to sunlight.
After “baking” in the sun for a time and rinsing in a water bath, brilliant Prussian blue images with white silhouettes emerge. It is this blue color that cyanotypes are named for. (The prefix “cyano-” which is derived from the Greek word kyanos, means "dark-blue.")
