Wiktionary
n. an early form of photographic material, in which the photosensitive emulsion was applied to a glass plate; latterly only used by astronomers
WordNet
n. a flat sheet of metal or glass on which a photographic image can be recorded [syn: plate]
Wikipedia
Photographic plates preceded photographic film as a capture medium in photography. The light-sensitive emulsion of silver salts was coated on a glass plate, typically thinner than common window glass, instead of a clear plastic film. Glass plates were far superior to film for research-quality imaging because they were extremely stable and less likely to bend or distort, especially in large-format frames for wide-field imaging. Early plates used the wet collodion process. The wet plate process was replaced late in the 19th century by gelatin dry plates. Glass plate photographic material largely faded from the consumer market in the early years of the 20th century, as more convenient and less fragile films were increasingly adopted. However, photographic plates were reportedly still being used by one photography business in London until the 1970s, and they were in wide use by the professional astronomical community as late as the 1990s. Workshops on the use of glass plate photography as an alternative medium or for artistic use are still being conducted.
A view camera nicknamed “The Mammoth” weighing was built by George R. Lawrence in 1899, specifically to photograph “The Alton Limited” train owed by the Chicago & Alton Railway, took photographs on a single glass plate measuring x .
Usage examples of "photographic plate".
It began in 1896 when Henri Becquerel in Paris carelessly left a packet of uranium salts on a wrapped photographic plate in a drawer.
He was attending a night seminar at the great telescope on Mount Wilson east of Cal Tech when he chanced to see an amazing photographic plate which showed one of the most distant galaxies, invisible to the unaided eye and to most telescopes, but absolutely perfect when caught in a giant telescope and held in focus on the photographic emulsion for eight hours.
Just as a photographic plate receives a different impression of a cluster of stars when a telescope is part of the intervening medium, so a brain receives a different impression when an eye and an optic nerve are part of the intervening medium.
But all we have to show for it are two tiny streaks on a photographic plate.
Well, when the two sets of waves crash against the photographic plate, some of the waves cancel out, leaving dark areas, and others reinforce each other, making the bright bands.
And he had previously prepared the photographic plate showing the yellow cloud, which he tossed overboard.
Three feet further away was a camera with a moving plate holder which carried a sensitized photographic plate.
A psychic, he went on, was like a sponge, a photographic plate with an unconscious that must look like an amusement park.
Becquerel had shown that by placing some uranium salt on a photographic plate, covered with black paper, the plate would be affected as if light had fallen on it.