Original cyanotype print on watercolor paper.
 
Cyanotype is a 170 year old photographic printing process that produces prints in a distinctive dark blue. This process uses the power of the sun and iron salt solutions .
The botanist Anna Atkins used the cyanotype printing process in 1843 to create an album of algae specimens. She produced the images by placing objects directly on photosensitive paper; this process is called a photogram. She is regarded as the first female photographer.