Mark Osterman is Photographic Process Historian at George Eastman House International Museum of Photography and Film in Rochester, NY. He teaches the technical evolution of photography from Niepce heliographs to making gelatin emulsions.
France Scully Osterman is an artist-educator, and lecturer at Scully & Osterman Studio and guest scholar at George Eastman House International Museum of Photography and Film, both in Rochester, NY. Scully is recognized for her extensive knowledge of early photographic processes including photogenic drawings, wet-plate and dry-plate collodion, albumen and salt print methods.
They mostly use a processes called calotype. Calotype is a photographic that uses a negative to produce onto a piece of uncoated paper, and creating a paper negative. A positive print can be made by pressing the negative under piece of glass against another piece of sensitive paper and exposing it to sunlight. The texture that is produce on to the can be seen by holding a piece of copier paper up to to light. This technique was in use principally from 1840 into the 1850s, when it was di Jones.
The amazing part of these images is the way they create an open mind to the viewer. A glance into what the viewer can image this is what they where doing in the late 1800's.