Richard Leach Maddox (August 4, 1816 – May 11, 1902) was an English photographer and physician who invented lightweight gelatin negative plates for photography in 1871. The 'wet plate' Collodion process had been invented in 1851 by Frederick Scott Archer. As a result, images required only 2 - 3 seconds of light exposure. But plates had to be sensitized at the time of exposure and processed immediately. While collodion dry plates had been available since 1855, thanks to Désiré van Monckhoven, it was not until Maddox's idea for the gelatin dry plate was realized that they rivaled wet plates in speed and quality. When he noticed that his health was being affected by the 'wet' collodion's ether vapor, he started looking for a substitute. He suggested in an 1871 British Journal of Photography article that sensitizing chemicals cadmium bromide and silver nitrate should be coated on a glass plate in gelatin, a transparent substance used for making candies. Eventually Charles Bennett made the first gelatin dry plates for sale; before long the emulsion could be coated on celluloid roll film. The advantages of the dry plate were obvious: photographers could use commercial dry plates off the shelf instead of having to prepare their own emulsions in a mobile darkroom. Negatives did not have to be developed immediately. Also, for the first time, cameras could be made small enough to be hand-held, or even concealed. While he did not patent the process, and died in poverty, Maddox received the Royal Photographic Society's Progress Medal in 1901.
