From the earliest days of photography, attention was devoted to finding a means of producing stable and consistent duplicates of images created by the new invention: daguerreotypes were unique, and the salted paper print was prone to fading. Talbot began his photographic engraving experiments primarily because he wanted to produce a photographic image which was permanent. Talbot’s research notes indicate that he had an interest in printing photographs in inks from as early as 1838. In the late 1840s, when he was already moving away from making his own photographs, he remained keen to further the progress of photography by exploiting the printing press. By 1852 Talbot had patented the first of his photogravure processes, the photographic engraving. Talbot went on to patent a second process, the photoglyphic engraving in 1858. Ultimately this process established the basis for photogravure and Talbot’s Fern is one of its the earliest examples.
‘The subject matter of Talbot’s earliest photogravures was a familiar echo of his earliest photogenic drawings, dominated by botanical specimens and bits of cloth … Talbot marvelled at how photography could naturally capture all the detail of an image simultaneously. These early photographic engravings are alluringly attractive to us today, in part because of their elegant simplicity and general consistency of tone.’ 
Inscribed by Talbot on recto in pencil, Copper & (?) Sized. Published in Sun Pictures, Catalog Number 12, Hans Kraus, Jr. #48 2003
The published state appeared in an article by Talbot, Photoglyphic Engravings of Ferns; with Remarks. A summary with a photoglyph, plate XIV, in: Transactions of the Botanical Society, Edinburgh, vol 7 (June 1863), p.569
Schaaf, Larry J, and Talbot. Sun Pictures, Talbot and Photogravure. New York: Hans P. Kraus, Jr., Inc, 2003. Plate 48.
Schaaf, Larry J, Sun Gardens: Victorian Photograms by Anna Atkins (New York: Aperture, 1985), figure 18.
Eugene Ostroff, The Photomechanical Process, in: Mike Weaver, ed., Henry Fox Talbot: Selected texts and bibliography, Oxford, 1992, pp125-130.
Leaf Prints Early Cameraless Photography and Botany Katharina Steidl
Charles H. Talbot – Some Account of Fox Talbot’s Process of Photographic Engraving, pg 3, 1902
 Schaaf, Larry J, and Talbot. Sun Pictures, Talbot and Photogravure. New York: Hans P. Kraus, Jr., Inc, 2003