The first camera photograph of a real scene needed hours or days of exposure
When Nicéphore Niépce pointed a camera obscura at Le Gras in 1826, his bitumen plate was so sluggish that the shutter effectively stayed open for hours, possibly days. Within about fifteen years, mercury fumes, silver iodide and a hot salt bath had cut that wait to minutes, and portraits became something ordinary people could sit for.
Sir John Herschel coined the word photograph in 1839, joining Greek roots for light and drawing. The idea behind it is simple: light lands on a sensitive surface, once film and now usually an electronic sensor, and leaves a picture. Niépce made the earliest permanent example in 1822, a contact copy of an engraving produced by a process he called heliography. In 1829 he teamed up with Louis Daguerre to find something faster.
Niépce died on 5 July 1833, and Daguerre pressed on with silver chemistry. He fumed a silver-plated copper sheet with iodine, exposed it for a few minutes, brought out the hidden image with mercury vapour and fixed it with hot salt water. He named the result the daguerreotype after himself. It was announced on 7 January 1839, though the method stayed secret until 19 August. Rivals soon trimmed exposures to seconds, and portrait studios flourished.
Daguerreotypes were fragile mirrors that had to be tilted just so, and each was a one-off. By the end of the 1850s cheaper ambrotypes and tintypes using the collodion process had displaced them, and glass collodion negatives printed onto albumen paper became the standard. A gelatin process arrived in 1871, and its descendants still underpin black-and-white film. Colour came surprisingly early in the lab, with Herschel's Anthotype prints in 1842 and the Lippmann process in 1891, but only became commercial with Autochrome plates in 1907. Kodachrome and Agfacolor Neu made it easy in the mid-1930s, yet most photographs stayed monochrome until the 1960s.
The digital era changed where pictures live. Tim Berners-Lee posted the first photograph on the web in 1992, an image of a CERN house band called Les Horribles Cernettes. Photography also stirred belief: because daguerreotypes had a mirrored surface, some spiritualists took them up as windows onto the soul, while others feared they could let demons in. Archivists today prefer acid-free buffered folders to plastic sleeves, which can trap moisture and make prints stick.
Source: Photograph
