Bennett, Charles Harper

SUBJECT AREA: Photography, film and optics

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b. 1840 Clapham, London, England

d. 1927 Sydney, Australia

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English inventor of the "ripening" technique for increasing the sensitivity of gelatine silver halide emulsions.

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The son of a hatter, Bennett studied medicine and was interested in mechanical devices, chemistry and later photography. An interior view shown at a South London Photographic Society meeting in March 1878 prompted requests for details of Bennett's procedure, and these were published almost immediately. It involved heating gelatine silver bromide for extremely long periods with an excess of silver bromide. The resulting emulsion had greatly enhanced sensitivity. This "ripening" process proved to be a major advance in the development of modern photographic emulsions. It was not patented and was soon widely adopted. Bennett's process became a key factor in the establishment of a new industry, the mass production of gelatine dry plates.

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Bibliography

1878, British Journal of Photography (29 March): 146; and 21 March 1879:71 (first published details of Bennett's process).

Further Reading

H.Gernsheim and A.Gernsheim, 1969, The History of Photography, rev. edn, London.

JW