William Henry Fox Talbot was born in the last year of the eighteenth century, and would be instrumental in making the image-saturation of the twentieth possible. He invented
photography.
In his spare time, Fox (as he was known, to his embarassment, by his friends) found the energy to be a Fellow of both the Royal Society and the Royal Astronomical Society, a member of Parliament for Chippenham, and pursue interests in antiquities, linguistics and biblical scholarship.
Talbot's friendship with Sir John Herschel and Dr. David Brewster initiated and fed his interest in light and optics, but his greatest innovation was born out of artistic frustration: Fox couldn't draw. Even the pseudo-cheat of using the camera lucida to project traceable images onto drawing paper was no help to him. He mused (as he later wrote) about "how charming it would be if it were possible to cause these natural images to imprint themselves durably, and remain fixed upon the paper." The year was 1833. AD.
Research into light-sensitive chemical reactions led to Talbot coating sheets of paper with alternate washes of sodium chloride and silver nitrate, creating a silver chloride compound. These he left lying around in the bright sunlight underneath leaves, coins, and other objects. The result, after many hours, was a "negative" (though this term would be coined, later, by Herschel) image of the shadow cast by the object; that is, the portions of the paper exposed to the sun turned a deep grey-brown, while the blocked portions remained white. Talbot dubbed these creations "sciagraphs": drawings of shadows. The images would fade after a short time, as the previously unexposed areas succumbed to ambient light and filled in. Talbot, through experimentation with salt solutions, determined that the images could be made permanent by washing with potassium iodide. The foundations of photography, exposure and fixation, were in place.
In 1834/35 Talbot began building crude cameras complete with lenses and loading them with his paper. These he would leave around his property to expose for hours before collecting the images. They were, at this point, still negatives only but were proper photographs. The major hurdle at this stage was practicality; multiple-hour exposure times severely limited possible subject matter. Unfortunately, Talbot was unavoidably distracted from his experiments by his other occupations and couldn't return to it until 1839. 1839, of course, was the year Louis Jacques Mande Daguerre went public with his process, effectively scooping Talbot.
Michael Faraday, another friend of Talbot's, attempted to champion Talbot's crown as the first mover of photography by displaying some of Talbot's 1835 images in a gallery. Talbot himself quickly tossed off a paper entitled "Some Account of the Art of Photogenic Drawing" and presented it to the Royal Society to defend himself. Daguerre, however, enjoyed the advantages of better results and publicity (with the strenuous backing of the French government). The inherent limitations of the daguerrotype, such as their irreproducibility and fragility, and the fact that the process itself was entirely different from Talbot's left Fox the room he needed to continue refining his work.
The exposure-time breakthrough happened in 1840, as Talbot was attempting to reapply his emulsion formula to used papers which had failed to produce an image. As he was rewashing the paper an image began to appear, and, with it, the concept of the latent image. Suddenly exposures of just a few seconds were feasible. Talbot dubbed his new invention the calotype, while his friends referred to it as the talbotype. Talbot now had the advantage over Daguerre: reproducible photographs.
In his competitive mood, Talbot patented the calotype process in England, Wales and France (though not Scotland) and charged enormous amounts for licenses. This effectively made him the only legal photographer in any of those countries which, of course, was a serious detriment to the advancement of the art of photography. Even the formation of a "calotype club" by would-be photographers to persuade Talbot to relax his patent had no success. It was not until the independent development of the superior, and patent-free, collodion photographic process (in 1851) that photography became open-source enough for serious refinement.
Sources: http://www.foxtalbot.arts.gla.ac.uk, http://www.rleggat.com/photohistory/history/talbot.htm, several photography classes (including one in which the teacher had such a heavy Massachusetts accent that she pronounced Talbot's name "Talbert", forever coloring my perception of his name)