Alfred Stieglitz has been celebrated as one of the greatest practitioners of the photogravure process, but his understanding and exploration of other photomechanical printing methods is less well known. While a mechanical engineering student at the Königliche Technische Hochschule, Berlin, in the mid-1880s, Stieglitz was introduced to photogravure and photomechanical processes by the renowned photo-chemist Professor Hermann Wilhelm Vogel (1834–1898), who convinced him that photography would be useful to his field of study.
Theodore Dreiser, “A Master of Photography,” Success Magazine 2 (10 June 1899), 471.
Dorothy Norman, Alfred Stieglitz: An American Seer (New York, 1973), 26.
Germany in the 1880s was “teeming with amateur photographers,” and Vogel, a staunch supporter of amateurism, founded the Deutsche Gesellschaft von Freunden der Photographie (German Society of the Friends of Photography) in 1887.
Stieglitz, “Correspondenz: zur Bildnung eines Amateur-Vereins,” Der Amateur-Photograph 1:3 (March 1887), 48.
The photogravure process was made possible by Alphonse Louis Poitevin’s significant discovery in 1855—that pigment could be combined with light-sensitive bichromated gelatin to make a print. Poitevin applied his findings to an experimental version of what would later be known as the carbon process, in which pigment (such as carbon black) suspended in bichromated gelatin was exposed to light under a negative, causing the gelatin to harden in areas that received more light, and remain soft in areas that received less light. The unhardened areas dissolved when washed with warm water, leaving a positive image of pigmented gelatin. The method became practical in the mid-1860s when the pigmented gelatin layers (tissues) became commercially available. Poitevin patented his carbon process, and, at the same time, a printing process using lithographic ink and a photographically prepared lithographic stone. Known as the collotype, it was further improved by Joseph Albert of Munich (1825–1886). Albert used glass plates coated with bichromated gelatin over a layer of hardened gelatin and exploited the ability of the gelatin to fracture in a fine reticulated pattern. After exposure to light through a positive image the plate was washed and then printed.
The reticulated pattern of the collotype can be seen under magnification, but to the naked eye the collotype appears to have a continuous tone, making it difficult to distinguish from a true photograph. By the 1880s the collotype displaced the Woodbury type, a photomechanical version of the carbon process patented by Walter Bentley Woodbury around 1865, as the highest-quality method of reproducing photographs.