Cyanotype is an old photographic process, invented in the mid-19th century.
It involves painting a surface (in this case paper) with a photosensitive solution that turns blue under the action of the sun. Any object placed on it during exposure to UV rays leaves a white imprint. The surface is rinsed with water to remove the excess product and stop the process, revealing a unique result. No camera is used to produce these images, which are called photograms.
It’s a fun way to immortalise plants.