No. 139a. Head of Niota Chute with Closing Dam [near Fort Madison, Iowa] 1885

Henry Bosse created this cyanotype print, ‘Head of Niota Chute with Closing Dam’ near Fort Madison, Iowa, sometime in the late 19th century. Bosse was a trained engineer working for the U.S. Army Corps of Engineers, so photography wasn't his primary occupation, but rather a tool. Cyanotype is an early photographic printing process, using iron salts that oxidize and turn blue when exposed to ultraviolet light. It's relatively simple, but requires careful preparation of the paper with a light-sensitive emulsion. The resulting image is a distinctive Prussian blue monochrome. Bosse's use of cyanotype speaks to the practical context of his work. The stark, almost diagrammatic quality of the print emphasizes the landscape's industrial alteration, the ‘closing dam’ referenced in the title. It also echoes the labor involved in taming the Mississippi River for navigation, subtly revealed through this beautiful, yet utilitarian medium. The level of handwork is considerable. Considering this history, we can appreciate the material reality of the photograph, and its relationship to the manipulation of the landscape it depicts.