John Vachon, “Grandmother of tenant farm family, Guilford County, North Carolina,” April 1938. Office of War Information Collection, Library of Congress, https://www.loc.gov/pictures/item/2017716972/. Post-processed electronically for contrast and detail.

You see her through a frame decorated with a pattern of sprocket holes. A flash occurred, the custodian of the frame moved an advance lever with his thumb, and the image was moved on toward its place in the historical record. Left behind in the wooden room was what was to remain of the face after the light had blasted it into the record. Left behind was the shadow cast by the hand warding off the light. Those had vanished in a flash.