Photographic plate

Photographic plate

Photographic plates preceded photographic film as a mean of photography. A light-sensitive emulsion of silver salts was applied to a glass plate. This form of photographic material largely faded from the consumer market in the early years of the 20th century, as more convenient and less fragile films were introduced. However, photographic plates were in wide use by the professional astronomical community as late as the 1990s. Such plates respond to ~2% of light received.


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. Many famous astronomical surveys were taken using photographic plates, including the first Palomar Observatory Sky Survey (POSS) of the 1950s, the follow-up POSS-II survey of the 1990s, and the UK Schmidt survey of southern declinations. A number of observatories, including Harvard University and Sonneberg Observatory, maintain large archives of photographic plates, which are used primarily for historical research on variable stars.

Scientific uses


Many solar system objects were discovered by using photographic plates, superseding earlier visual methods. Discovery of minor planets using photographic plates was pioneered by Max Wolf beginning with his discovery of 323 Brucia in 1891. The first natural satellite discovered using photographic plates was Phoebe in 1898. Pluto was discovered using photographic plates in a blink comparator; its moon Charon was discovered by carefully examining a bulge in Pluto's image on a plate.


Photographic plates were also an important tool in early high-energy physics, as they get blackened by ionizing radiation. For example, Victor Franz Hess discovered, in the 1910s, cosmic radiation as it left traces on stacks of photographic plates, which he left for that purpose on high mountains or let into the even higher atmosphere using balloons.

Medical imaging

The sensitivity of certain types of photographic plates to ionizing radiation (usually X-rays) is also a useful in medical imaging and material science applications, although they have been largely replaced with reusable and computer readable image plate detectors and other types of X-ray detectors.


Use of photographic plates has declined significantly since the early 1980s, replaced by charge-coupled devices (CCD). CCD cameras have several benefits over glass plates, including highly efficient, linear response to light, and simplicity of image acquisition and processing. However, even the largest format CCDs (e.g. 8192x8192 pixels) still do not have the detecting area and resolution of most photographic plates, which has forced modern survey cameras to use large arrays of CCD chips. The longevity of electronic data and data formats (such as FITS) is also uncertain.


* Peter Kroll, Constanze La Dous, Hans-Jürgen Bräuer: "Treasure Hunting in Astronomical Plate Archives." (Proceedings of the international Workshop held at Sonneberg Observatory, March 4 to 6, 1999.)" Verlag Herri Deutsch, Frankfurt am Main (1999), ISBN 3-8171-1599-7

ee also

*film base

External links

* [ The Sonneberg Plates Archiv (Sonneberg Observatory)]

Wikimedia Foundation. 2010.

Игры ⚽ Нужно сделать НИР?

Look at other dictionaries:

  • photographic plate — fotografinė plokštelė statusas T sritis chemija apibrėžtis Plokštelė, padengta šviesai jautria medžiaga. atitikmenys: angl. photographic plate; photoplate rus. фотопластинка …   Chemijos terminų aiškinamasis žodynas

  • photographic plate — fotoplokštelė statusas T sritis fizika atitikmenys: angl. photographic plate; photoplate vok. Photoplatte, f rus. фотопластинка, f pranc. plaque photographique, f …   Fizikos terminų žodynas

  • photographic plate — noun a flat sheet of metal or glass on which a photographic image can be recorded • Syn: ↑plate • Hypernyms: ↑sheet, ↑flat solid • Hyponyms: ↑quarter plate …   Useful english dictionary

  • photographic plate — noun an early form of photographic material, in which the photosensitive emulsion was applied to a glass plate; latterly only used by astronomers …   Wiktionary

  • Photographic plate — Фотопластинка …   Краткий толковый словарь по полиграфии

  • Plate — may refer to: * Plate (dishware) * Plate (structures), a type of foundation * A flat piece of metal used in orthopedics to connect the two parts of a broken bone, such as a dynamic compression plate * Plate armor, body armor made of metal plates… …   Wikipedia

  • Photographic film — This article is mainly concerned with still photography film. For motion picture film, please see film stock. Photographic film is a sheet of plastic (polyester, nitrocellulose or cellulose acetate) coated with an emulsion containing light… …   Wikipedia

  • photographic magnitude — noun : the magnitude of a celestial body as determined by observations with an ordinary blue sensitive photographic plate …   Useful english dictionary

  • Photographic processing — is the chemical means by which photographic film and paper is treated after photographic exposure to produce a negative or positive image. Photographic processing transforms the latent image into a visible image, makes this permanent and renders… …   Wikipedia

  • Photographic developer — In the processing of photographic films, plates or papers, the photographic developer (or just developer) is a chemical that makes the latent image on the film or print visible. It does this by reducing the silver halides that have been exposed… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”