Photogenic Drawing and the Calotype

William Henry Fox Talbot (1800-1877)

William Henry Fox Talbot worked in England in the early 1830s. He invented a way of recording images that remains the basis for photography today: the negative-positive system.

Talbot soaked paper in a solution of common salt and, when it was dry, in a solution of silver nitrate. This created silver chloride, a chemical that darkens when exposed to light. When light fell on the paper in the camera, it produced a negative image. Talbot's early negatives, or "photogenic drawings," required exposure times of several hours. As he perfected his process, Talbot reduced the exposure time, producing "latent" images that he could develop chemically. He called these negatives "calotypes," from the Greek kalos (beautiful) and the Latin typus (image). Talbot could make an unlimited number of positive prints by placing a negative in contact with a sheet of sensitized paper and exposing the whole to light.

Talbot was taken by surprise when Frenchman Louis Jacques Mandé Daguerre announced his daguerreotype process to the world in 1839. He rushed to publish the results of his own experiments, and claim priority of invention over Daguerre. Though his process was widely used until the 1850s, Talbot never received the recognition given Daguerre.