Woodward's photomicrography apparatus, Washington, D.C., about 1876. The invention of photomicrography. In the 1870s, U.S. Army surgeon Joseph Janvier Woodward invented a technique of photographing objects seen under a microscope. Woodward's photomicrographs, made with a room-sized apparatus that used direct sunlight as the light source, caused a sensation when exhibited at the 1876 Centennial Exposition in Philadelphia. After further development, photomicrography enabled forensic investigators to make visual records of what they saw. The photographs served as an aid to analysis and could be presented as evidence in the courtroom.