Cyanotype of the Adiantum serrulatum fern, 1853.
© National Media Museum / Science & Society Picture Library
From 'British and Foreign Ferns', an album of ferns published in 1853 for presentation to CSA by Anna Atkins (1799-1871). Atkins is credited with having produced the first book to use photographic illustrations. The 'blueprint' proces used to make the image employs ferric salts to produce a light sensitive solution coated onto a sheet of paper. After exposure it is permanently fixed by washing in plain water. The image is white on a blue background, and is highly durable and stable.