What is cynotype?

Cyanotype is a photographic printing process that produces a blue print. It was invented in the mid 19th century by Sir John Herschel, but it was later popularized by Anna Atkins who used the process to create cyanotype photograms of botanical specimens.

The process involves coating a piece of paper or fabric with a mixture of iron compounds, typically ferric ammonium citrate and potassium ferricyanide. The coated material is then exposed to UV light, either by placing objects or negatives directly on the coating or by using a contact printing frame.

The UV light triggers a chemical reaction that results in a blue color where the light hits the coating. After exposure, the coated material is rinsed with water to stop the reaction and fix the image.

Cyanotype prints have a distinctive blue color, which can vary from a pale blue to a deep, rich blue depending on the exposure time and the formulation of the chemicals. The process is simple and requires only a few basic materials, making it a popular technique for both artistic and scientific applications.