Two hundred years ago, a French inventor fixed the first permanent photograph on a pewter plate. Since then, engineering advances have transformed that eight-hour exposure into two trillion images a year. Here, E+T identifies the most significant and rates their influence today.
The chemical process: making photography repeatableOn 7 January 1839, the French Academy of Sciences announced that Louis Daguerre (pictured) had perfected a process for fixing camera images on silver-coated copper plates with extraordinary sharpness and detail. The technical specifics were withheld, but the news reached England on 19 January. William Henry Fox Talbot, who had been developing his own paper-based photographic process since 1834, responded immediately. On 25 January, he exhibited paper photographs he had made in 1835 at the Royal Institution; by 31 January, he had communicated the full principles to the Royal Society, six months before France released the daguerreotype’s working details on 19 August...