Today marks the birthday of Anna Atkins, a British botanist whose use of cyanotypes - or 'sunprints' - of plants and algae in botanical studies paved the way for the use of photography in scientific publishing.

Now versions of her beautiful photographic images are being used as a Google doodle to celebrate the 216th anniversary of her birth, in 1799. The delicate leaves used to spell out the name of the search engine are slate blue against a darker blue background. This is due to the cyanotype process, which involves the exposure of a mix of ammonium iron citrate and potassium ferricyanide to ultraviolet light, leaving the paper so-called Prussian blue.

In fact, the word 'blueprint' comes from the same process, which had previously been used to reproduce architectural drawings and designs. Atkins' claim to fame rests on her realisation that the photographic process could be used to give accurate and detailed botanical images, thus advancing the possibility of scientific illustration. She did this by placing leaves directly on the paper for the length of the exposure, which makes these, strictly speaking, photograms, rather than photographs.

Ann Atkins' use of cyanotypes in botanical books was a first for scientific publishing, and for photography

However, Atkins' first book using the technique didn't show leaves such as those we see in today's Google Doodle. Instead this was Photographs of British Algae, in 1843, a privately published collection with handwritten captions to the individually produced cyanotypes.

It was her mentor - and the inventor of the cyanotype process - English astronomer Sir John Herschel, who produced the first commercially published book illustrated with photographs, The Pencil of Nature, in 1844.

Anna Atkins' photograms - In pictures Show all 8 1 /8 Anna Atkins' photograms - In pictures Anna Atkins' photograms - In pictures Cyanotype photograms A cyanotype photogram made by Atkins which was part of her 1843 book, 'Photographs of British Algae: Cyanotype Impressions' Anna Atkins/Public Domain Anna Atkins' photograms - In pictures Cyanotype photograms Cystoseira granulata, a type of brown algae, published in 'Photographs of British Algae: Cyanotype Impressions' Anna Atkins/Public Domain Anna Atkins' photograms - In pictures Cyanotype photograms A Wood Horsetail from the 1853 book Cyanotypes of British and Foreign Ferns by Atkins and Anne Dixon. Anna Atkins/Public Domain Anna Atkins' photograms - In pictures Cyanotype photograms Foreign Ferns circa 1845-1855. Public Domain Anna Atkins' photograms - In pictures Cyanotype photograms A cyanotype by Atkins. Public domain Anna Atkins' photograms - In pictures Cyanotype photograms Carix cyanotype photogram circa 1850, Public domain Anna Atkins' photograms - In pictures Cyanotype photograms Sargassum bacciferum a type of brown algae. Public Domain Anna Atkins' photograms - In pictures Cyanotype photograms A cyanotype photogram of festuca grasses. Public domain

Atkins was born in Tonbridge in Kent and received an unusually scientific education for a woman of her time, following in the footsteps of her father, John George Children. Long before her experiments with cyanotypes, her engravings of shells were used to illustrate her father's translation of a book on the subject.

After her book on algae, she collaborated with Anne Dixon on at least two more botanical books, Cyanotypes of British and Foreign Ferns and Cyanotypes of British and Foreign Flowering Plants and Ferns.