Nineteenth-century cyanotypes — an early form of photography that create a negative image on a blue background — capture the delicate beauty of British algae, in images taken by botanist Anna Atkins, the first woman to experiment with photography.
"Photographs of British Algae: Cyanotype Impressions," by British photography pioneer and botanist Anna Atkins (1799-1871), is a 19th-century botanical volume, which Atkins self-published in 1844.
A copy of the historic volume, the first book to be illustrated with photographs, was recently acquired by the Rijkmuseum in the Netherlands.
Cyanotypes, an early form of photographic printing, uses chemicals and sunlight to create a negative image of an object silhouetted against a blue background.
Cyanotypes were created by treating paper with ferric ammonium citrate and potassium ferricyanide — iron salts that dissolve in water — and then placing an object on the paper and exposing it to sunlight.
The cyanotype process forms a compound called Prussian blue,tinting the paper treated with iron salts a shade of deep blue.
"Photographs of British Algae" contains 307 images of algae native to waters in and around Great Britain.
Atkins produced several editions of "Photographs of British Algae," of which about 20 copies — complete and incomplete — survive today.
Atkins produced thousands of algae cyanotypes for her books, a process that took 10 years, according to Rijksmuseum officials.
In later years, Atkins collaborated with Anne Dixon (1799–1864), another female botanist, to produce two additional books illustrated with cyanotypes: "Cyanotypes of British and Foreign Ferns" (1853) and "Cyanotypes of British and Foreign Flowering Plants and Ferns" (1854).
Atkins' pioneering work using cyanotypes helped to establish photography as a medium for accurately representing scientific specimens.