Wet-plate photography was the only technique available for most of Jackson's USGS expeditions. The process involves preparation of a glass plate with several chemical solutions, exposing the plate for a few minutes, and then developing the resulting negative with more chemical fixatives. The larger the glass plate, the better the image quality.
Before working for the USGS, Jackson had photographed in the prairies outside Omaha using a "dark room on wheels." On expedition, toting his fragile glass plates, large quantities of water and chemicals, portable "dark room" tents, and bulky cameras across rugged terrain was far more difficult. Following his initial success with a modest 7 x 9 inch camera in 1870, an 8x10 inch camera was added in 1871. Jackson experimented with a larger 11 x 14 inch camera starting with his 1872 exploration of the Grand Tetons. In 1875 he brought along a large-format 20 x 24 inch camera, but it was too unwieldy for subsequent field seasons.
Work on the Centennial International Exposition exhibition introduced Jackson to dry-plate photography. This new technology allowed plates to be prepared ahead of time and developed long after exposure, streamlining the photographic process and reducing the amount of equipment needed. Unfortunately, Jackson's 1877 experiments with dry-plate photography in the arid Southwest were unsuccessful, and all his images from that year were unusable. He called it "…the biggest disaster of my career," and returned to using wet-plate photography on his final expedition with the USGS.
While advances in photographic processing ended Jackson's studio work, he used new technologies such as photolithographs and roll film cameras in his later years.
