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Sir John Frederick William Herschel was British photographer, scientist, inventor mathematician, astronomer, chemist and biologist who did botanical studies. He was born March 7, 1792 in Slough, Great Britain and died May 11, 1871 in Collingwood, Great Britain. He was the son of astronomer Friedrich Wilhelm Herschel.
Herschel made several contributions to photography. He invented several processes including the cyanotype and chrysotype and made improvements to several other processes. He experimented with color reproduction, noting that rays of different parts of the spectrum tended to impart their own color to a photographic paper. Herschel originally discovered the platinum process on the basis of the light sensitivity of platinum salts, later developed by William Willis. Herschel coined the term photography in 1839, a term which he used in a paper entitled "Note on the Art of Photography, or The Application of the Chemical Rays of Light to the Purpose of Pictorial Representation," presented to the Royal Society on March 14th 1839, unaware that the term photography had already been coined by Hercules Florence in 1834. He also applied the terms negative and positive to photography.
Arguably his greatest contribution to photography occurred, when he discovered that sodium thiosulfate was a solvent of silver halides in 1819. Herschel informed W. H. F. Talbot and Daguerre of this discovery. After applying hyposulphite of soda ("hypo") he determined it could be used as a photographic chemical fixer, to permanently "fix" pictures and allow the images to be permanent. His research on the subject was read at the Royal Society in London in March 1839 and January 1840.
In other areas, Herschel was a noted scientist, In 1809 he entered the University of Cambridge; in 1812 he submitted his first mathematical paper to the Royal Society, of which he was elected a fellow the following year. In 1820 Herschel became a founding member of the Royal Astronomical Society. From 1833 until 1838, his astronomical investigations brought him and his family to the Cape of Good Hope in South Africa, where he met Julia Margaret Cameron, who became a lifelong friend. In 1850 Herschel was appointed master of the Mint, but he resigned six years later due to poor health. His remaining years were spent working on his catalogs of double stars and of nebulae and star clusters. The only son of the distinguished British astronomer William Herschel, Sir John himself also became a well-known astronomer, and published an influential book on the subject. Among his contributions to astronomy, Herschel, named seven moons of Saturn, four moons of Uranus, discovered solar nebulae and originated the use of the Julian day system. Herschel studied color blindness and the chemical power of ultraviolet rays.