By 1841, an Englishman, William Henry Fox-Talbot, had refined this process and made two major advances in the photographic process. The first was the 'latent image' concept - that it was not necessary to wait for the image to develop inside the camera; instead, exposure times could be cut dramatically if the image was later amplified or developed using a chemical process.
He also found that, unlike the Daguerrotype which produced a pale-grey positive image, his light-sensitive photographic paper turned black when exposed to light and showed a negative image. Any number of positive images could then be obtained by exposing photographic paper to light filtered through the original — a process he called the 'Calotype'. And so the negative was born and with it the introduction of mass production.
Fox-Talbot also had a geological connection: he is known to have been acquainted with Sir Henry De la Beche , the first Director of what we now know as the British Geological Survey, and to have photographed him on several occasions.
The science of photography saw several more quasi-alchemistic processes over the following 40 years until, in 1888, an American bank clerk, George Eastman, patented a small portable camera containing a roll of cellulose film long enough for 100 exposures.
When the film had been fully exposed, the whole camera was sent back to the factory for the film to be processed and printed. The camera was then reloaded with film and returned to the customer. Eastman called this product the 'Kodak'; he chose the name he because it could be pronounced the same in any language.