|Arietidæ plate using heliogravure copper platting|
Hyatt co-founded the American Naturalist, serving as their editor from 1867 to 1870. He became a professor of paleontology and zoology at Massachusetts Institute of Technology in 1870, where he taught for eighteen years, then Professor of Biology and Zoology at Boston University from 1877 until his death in 1902.
Hyatt favoured the use of héliogravure, the technique used here to illustrate some of the best early American ammonite plates. Heliogravure is a type of photogravure or intaglio printmaking or photo-mechanical process whereby a copper plate is grained and then coated with a light-sensitive gelatin tissue exposed to a film positive, then etched.
In France, the correct term for photogravure is héliogravure, while the French term photogravure refers to any photo-based etching technique. The earliest forms of photogravure were developed by two of the original pioneers of photography — first by Nicéphore Niépce in France in the 1820s, and later Henry Fox Talbot in England.
Niépce was seeking a means to create photographic images on plates that could then be etched and used to make prints on paper with a traditional printing press. Niépce's early images were amongst the first photographs — pre-dating daguerreotypes and the later wet collodion photographic process. Henry Talbot, the inventor of the calotype paper negative process, wanted to make paper prints that would not fade. He worked on his photomechanical process in the 1850s and patented it in 1852 ('photographic engraving') and 1858 ('photoglyphic engraving').
Photogravure in its mature form was developed in 1878 by Czech painter Karel Klíč, who built on Talbot's research. This process, the one still in use today, is called the Talbot-Klič process.
Because of its high quality and richness, photogravure was used for both original fine art prints and for photo-reproduction of works from other media such as paintings. A photogravure is distinguished from rotogravure in that photogravure uses a flat copper plate etched rather deeply and printed by hand, while in rotogravure, as the name implies, a rotary cylinder is only lightly etched, and it is a factory printing process for newspapers, magazines, and packaging.
Many of my favourite paleontological plates were created using this technique. We're fortunate that it allows for both a high degree of detail and multiple printings, ensuring that these beautiful and important early works were not lost in time.
S. S. B. (1890). II.—The Genesis of the Arietidæ. By Professor Alpheus Hyatt. Smithsonian Contributions to Knowledge, 673. 4to. pages vii–xi, 1–223; 14 Plates and 35 Woodcuts. (Washington, 1889.). Geological Magazine, 7(7), 325-326. doi:10.1017/S0016756800186790
Talbot's Correspondence: Biography. De Montfort University.