12 January 2008

William Henry Fox Talbot

Portrait of William Henry Fox Talbot, Ivan Szabo
salt print from a glass negative, mid 1850s. 13.3 x 10.7 cm.
source: http://foxtalbot.dmu.ac.uk/resources/portrait2.html

"William Henry Fox Talbot (February 11, 1800 – September 17, 1877) was the inventor of the negative/positive photographic process, the precursor to most photographic processes of the 19th and 20th centuries".
William Fox Talbot -Wikipedia article

A different evaluation of the role of Talbot in the development of photography is proposed by R. Derek Wood: "Talbot’s part in the birth of photography in 1839 has generally been overrated in England". He writes:

"Talbot laid considerable emphasis upon sensitization with silver iodide/gallic acid mixture before exposure. As late as 1844 he still seemed to place importance on this pre–exposure wash with gallic acid “to bring out the picture”. [31] The words “latent” and “develop” certainly appear in his first account of the calotype process, but how clearly did he conceive of the development of the latent image? The calotype process presented practical difficulties so that it was still not so widely used as the daguerreotype in the 1840s. [32] If the calotype was really so basic a beginning to modern photography can the early practical failure of the technique be solely due to the fact that the negative base was paper? Did other photographers fail to read from the published technique an understanding of the development of the latent image?

John Herschel, in contrast to Talbot, always sought to understand the principles involved in the photographic process, and his published articles were therefore always stimulating to other researchers. In the first two years of photographic research he did not, however, observe what has proved to be so remarkable a characteristic of silver salts and the reason why they are so important for the advance of photography; important not simply because they change when exposed to light (for many substances do this) but because development by chemical reduction can be obtained on silver halide crystals after they have received only an extremely low exposure. But it is not surprising that photography should have first to pass through a primitive stage using an exposure print–out system before a mature understanding could be reached of latent image formation and a mode of working using chemical development could be established. It is commonly held that the calotype is of absolute significance and Talbot’s role supreme in the discovery of the latent image and development. Whether or not such assumptions are entirely correct, it is within this context that the present article has attempted to clarify a confused aspect of the pre–history of development in the hope that future studies on the subject can be more straight forwardly and relevantly pursued."

in Latent Developments from Gallic Acid, 1839
by R. Derek Wood
Journal of Photographic Science, 28: 1 (January/February 1980), pp. 36–41
available here

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