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 scientist was Sir John Frederick William Herschel, and in 1842, he invented the cyanotype process—a form of alternate photography that creates blue and white images (aka, blueprints) by using photography chemicals and sunlight to create image imprints.
A year later, botanist Anna Atkins famously used Herschel’s process to document algae specimens, becoming the first person to illustrate a book with 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 “painted” onto 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.")
