Talbot, William Henry Fox (1800–1877)

English pioneer of photography. He invented the paper-based calotype process, patented in 1841, which was the first negative/positive method. Talbot made photograms several years before Louis Daguerre's invention was announced.

Talbot was born in Melbury, Dorset, and studied at Cambridge. He was elected Liberal member of Parliament for Chippenham in 1833. During a trip to Italy he tried to capture the images obtained in a camera obscura and by 1835 had succeeded in fixing outlines of objects laid on sensitized paper. Images of his home, Lacock Abbey, Wiltshire, followed.

In Talbot's calotype process, writing paper was coated successively with solutions of silver nitrate and potassium iodide, forming silver iodide. The iodized paper was made more sensitive by brushing with solutions of gallic acid and silver nitrate, and then it was exposed (either moist or dry). The latent image was developed with an application of gallo-silver nitrate solution, and when the image became visible, the paper was warmed for one to two minutes. It was fixed with a solution of potassium bromide (later replaced by sodium hyposulphite). Calotypes did not have the sharp definition of daguerreotypes and were generally considered inferior.

Talbot patented an enlarger in 1843. In the decade to 1851, he took out some patents that contained previously published claims, but in 1852 he cleared the way for amateurs to use processes developed in other countries. Talbot was also a mathematician and classical scholar, and was one of the first to decipher the cuneiform inscriptions of Nineveh, Assyria.

A museum of his work was opened at Lacock Abbey, Wiltshire, in 1975.