Photogravure is a photo-mechanical process that allows photographs to be reproduced using printer's ink. Original, chemical photographs can be printed singly or in books and keep their range of silky tones from dark to light. Introduced in the 1880s, photogravure was so fine that, in the best examples, photographs could look like beautiful etchings. But it was an expensive process, which limited its use in publishing books, though not among artists producing limited editions.

Although Emerson produced only 200 copies of Life and Landscape on the Norfolk Broads , altogether they contained thousands of original platinum prints laid in by hand. This was impractical. The way forward was photomechanical reproduction. Emerson chose gravure for the plates in his other photographically illustrated books. Photogravure kept faith with the realism of photographs and often increased their beauty. Books printed in this way remained expensive but at least their images looked like photographs.

Emerson's last great book was Marsh Leaves (1895), which his enemies dismissed as a ‘trifle'. Emerson, it seemed, had stopped trying to stamp his methods on art photography. He decided to become a writer and novelist. But he is remembered now for his photographs because they were truly original.