'Polysiphonia violacea', 1843.
© National Media Museum / Science & Society Picture Library
'Photographs of British Algae: Cyanotype Impressions' 1943. Cyanotype Impressions was published in ten installments from 1843-1853, starting with Part 1 in 1843. Atkins is credited with having produced the first book to use photographic illustrations. The 'blueprint' process 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 water. The image is white on a blue background, and is highly durable and stable.