Sir John Frederick William Herschel was born in Buckinghamshire, England in 1792.
Despite a strong interest and talent in mathematics, he went to London to study law. After 18 months of study he decided law was not to his liking and moved back to Cambridge where he became a tutor in mathematics. When his father became ill, Herschel decided to follow in his footsteps and continue his practise in astronomy. Fortunately for photographers Herschel explored many scientific interests.
In 1819 Herschel discovered that hyposulphite of soda dissolved silver salts. Eventually this formulation would simply be called hypo, a fixing agent used to this day in "wet" darkrooms.
It would be another 20 years before Daguerre and Talbot would release their respective "light drawing" processes and ultimately incorporated Herschel's hypo in their work flow.
Collection of Archive, Royal Society, London, England
Within days of learning of Daguerre's announcement, Herschel was adapting, had moved from polished copper to using clear glass as a substrate to create a negative image from which he could make copies on paper. He called this process "retransfer" and on February 14, 1839 writes "The enigma of the "exalting glass grows more obscure."
From this "retransfer" process, Herschel also gives us the words "positive" and "negative" as applied to photography. On February 14, 1839, he writes the word "photography" in his journal, the first such time the word is used to describe "painting with light." His most important paper, arguably, “On the Art of Photography; or the Application of the Chemical Rays of Light to the Purpose of Pictorial Presentation”, was read to the Royal Society on March 14, 1839. In this paper Herschel put to use the words “photography”, “positive” and “negative”.
Sir John Herschel - a photographic genius who deserves his rightful place alongside the early pioneers of the medium.