Light sensors
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Obtaining an image by means of a darkroom has been known since antiquity: when a closed box is pierced with a small hole, the image of an object illuminated outside is formed on the opposite wall of the the box.
But it was not until the 19th century that it was found how to fix this image.
- Around 1824, Nicéphore Niepce found a way to preserve this image on a silver plate, after exposing it to light for several days in a row...
- 1838: Louis Daguerre introduced photographic processing: a plate is first exposed for a shorter time before being placed in mercury vapor to reveal the image in a second time;
- 1839: William Talbot invents the negative: colors (or shades of gray) are reversed on paper, so that they can then be reproduced multiple times (positives) without altering the original
- 1840: the first attempts at color photography take place.
- 1847: Abel Niepce uses glass, thus obtaining better quality images.
- The glass plate in the photo above actually contains two images, allowing to see in relief thanks to a stereoscopic shot
- 1888: George Eastman uses a flexible support, easier to handle:
- The Eastman company, then Eastman-Kodak, which he created, marketed the first photographic films, of which the 35 mm format (roll width) which turned into an industry standard.
- The most common standard in photography became the 24x36: 24 mm high and 36 mm wide.
- 1903: the Lumière brothers develop the first truly practical colour photography process.
The first electronic sensors born in the AT&T and Bell laboratories in 1969 revolutionized photography:
- The photons are captured by electronic receivers which transform the light intensity into electric current.
- This technology now equips digital cameras, smartphones and other visual equipment.
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The image above includes a picture of a sensor for compact camera.
