1839 - Fox Talbot announced the first positive/negative process within weeks of Daguerre.

William Henry Fox Talbot (1800 – 1877) was an English MP, scientist, inventor and amateur artist now best remembered as the father of the negative-positive process that is the basis of modern analogue photography. While on honeymoon in Italy in 1833 he was dissatisfied with his ability to sketch the landscapes. On his return, he experimented with ways to capture and retain the images cast in a camera obscura. On hearing the unexpected news of the invention of the daguerreotype, Talbot scrambled to make a public claim and within weeks had presented details to the Royal Society in London showing several paper photographs he had made in 1835.

At the time of Talbot’s announcement, his ‘art of photogenic drawing’ was better suited for recording the shadows of plant specimens or inanimate objects by direct contact – now known as photograms – than for camera images of people or scenes.

The Calotype process

This process uses a paper negative to make a print with a softer, less sharp image than the daguerreotype, but because a negative is produced, it is possible to make multiple copies. In this technique, a sheet of paper coated with silver chloride was exposed to light in a camera obscura; those areas hit by light became dark in tone, yielding a negative image.

The revolutionary aspect of the process lay in Talbot’s discovery of a chemical (gallic acid) that could be used to ‘develop’ the image on the paper—i.e., accelerate the silver chloride chemical reaction to the light it had been exposed to. The developing process permitted much shorter exposure times in the camera, down from one hour to one minute.

Patents
Talbot patented his process in 1841, which meant it was never taken up widely in the commercial sphere where the Daguerreotype was the preferred method. Instead, the calotype was adopted by amateurs, artists and scientists. This patent, and challenges to its perceived infringement by Frederick Scott Archer’s wet collodion process, have, perhaps unjustly, tarnished Talbot’s reputation. Lord Rosse, then President of the Royal Society, was to the fore in persuading him to relinquish the patent. In any case, the process was superseded in the mid 1850s by the wet collodion process.

Photo-engraving
Talbot’s achievements in photo-engraving have tended to be neglected, but they are of enormous significance in the development of mass circulation photography.
In 1852 he patented his ‘photographic engraving’ process, which produced an intaglio plate that could be printed by conventional methods—the final rendering of the photographic image was in stable printer’s ink. By 1858 he had evolved a much improved process which he called ‘photoglyphic engraving’ and a second patent was granted. These were direct ancestors of the modern photogravure process, and while they did not succeed commercially within his lifetime, Talbot was on absolutely the right track in this pursuit. He continued to perfect these processes until the end of his life, finally spending more time on photomechanical printing than he ever had on photography. The 1862 International Exhibition in London awarded him a prize medal for photoglyphic engraving.

Talbot was in direct communication with many of the leading Irish photographic pioneers including Lord Rosse and Mary Parsons, Countess of Rosse, William Holland Furlong, the King Tenisons and Francis Stewart Beatty.