The cyanotype process is an old form of photography that creates blue and white image imprints (also commonly known as blueprints!).

It was invented in 1842 by British scientist Sir John Frederick William Herschel. 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.

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 applied to paper. Objects (botanicals) 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 white-silhouetted-and-Prussian-blue images emerge.

It is this blue color that cyanotypes are named for. (Cyano which is derived from the Greek word kyanos, means "dark-blue.")

For more on Tiffany’s personal approach to cyanotypes, check out the FAQs page.