Editing Lippmann plate

[[File:Gabriel Lippmann Le Cervin 1891-1899.jpg|thumb|Early colour photograph (circa 1891–1899) by Lippmann of the [[Matterhorn]]]]

'''Lippmann process photography''' is an early [[color photography]] method and type of [[alternative process]] photography. It was invented by French scientist [[Gabriel Lippmann]] in 1891 and consists of first focusing an image onto a [[Photographic plate|light-sensitive plate]], placing the [[Photographic emulsion|emulsion]] in contact with a mirror (originally liquid [[Mercury (element)|mercury]]) during the [[Exposure (photography)|exposure]] to introduce [[wave interference|interference]], [[Photographic developer|chemically]] [[Photographic processing|developing]] the plate, inverting the plate and painting the glass black, and finally affixing a [[Prism (optics)|prism]] to the emulsion surface. The image is then viewed by illuminating the plate with light. This type of photography became known as '''interferential photography''' or '''interferometric colour photography''' and the results it produces are sometimes called '''direct photochromes''', '''interference photochromes''', or '''Lippmann photochromes''' (distinguished from the earlier so-called "[[Photochrom|photochromes]]" which were merely black-and-white photographs painted with color by hand).<ref name=Eder668,670-672>{{cite book | last = Eder | first = J.M. | title = History of Photography, 4th. edition |trans-title=Geschichte der Photographie| year = 1945 | orig-year =  1932 |  publisher = Dover Publications | location = New York | pages = 668, 670, 671, 672 | isbn = 0-486-23586-6}}</ref><ref>{{patent|US|6556992}}</ref> In French, the method is known as ''[[:fr:photographie interférentielle|photographie interférentielle]]'' and the resulting images were originally exhibited as ''des vues lippmaniennes''. Lippmann won the [[Nobel Prize in Physics]] in 1908 "for his method of reproducing colours photographically based on the phenomenon of interference".<ref name=NPsummary>{{Cite web |url=https://www.nobelprize.org/prizes/physics/1908/summary/ |title=The Nobel Prize in Physics 1908 |year=2024 |website=NobelPrize.org |publisher=Nobel Prize Outreach AB 2024 |location=Stockholm |access-date=26 October 2024}}</ref>

Images made with this method are created on a '''Lippmann plate''': a clear glass plate (having no [[anti-halation backing]]), coated with an almost transparent (very low silver halide content) [[emulsion]] of extremely fine grains, typically 0.01 to 0.04 micrometres in diameter.<ref>R.W.G. Hunt, ''The Reproduction of Colour'', 6th ed, p6</ref>
Consequently, Lippmann plates have an extremely high resolving power<ref>{{cite web |url=http://www.tpub.com/content/photography/14209/css/14209_56.htm |title=Emulsion Definition |website=www.tpub.com |access-date=12 January 2022 |archive-url=https://web.archive.org/web/20100724065137/http://www.tpub.com/content/photography/14209/css/14209_56.htm |archive-date=24 July 2010 |url-status=dead}}</ref> exceeding 400 lines/mm.

==Method==
[[File:Colodión húmedo, collodion wet plate process, el colodión se vierte en una placa de vidrio, IPCE, Madrid, España.jpg|thumb|right|alt=An artist wearing gloves pours liquid salt collodion onto a glass plate.|To create a Lippmann plate, a [[Photographic emulsion|light-sensitive emulsion]] of [[silver halide]] dispersed in [[gelatin]] is coated onto a glass [[photographic plate]] ''(Shown here: [[collodion|collodion solution]])''. Later, the back is painted black and a prism is glued to the front to control reflection.]]
In Lippmann's method, a glass plate is coated with an ultra fine grain<ref>"[http://spiedigitallibrary.org/proceedings/resource/2/psisdg/3358/1/95_1?isAuthorized=no Recent developments in Lippman photography"], Jean-Marc Fournier, Benjamin R. Alexander, et al.;Proc. SPIE 3358, 95 (1998)</ref> light-sensitive film (originally using the [[Albumen print|albumen process]] containing [[potassium bromide]]; later and primarily using [[Gelatin silver print|silver halide gelatin]]),<ref name=HOP>{{cite journal |last1=Bjelkhagen |first1=Hans |date=19 Jan 2015 |title=Lippmann photography: Reviving an early colour process |url=https://www.tandfonline.com/doi/abs/10.1080/03087298.1999.10443331 |journal=[[History of Photography (journal)|History of Photography]] |publisher=[[Taylor & Francis]] |doi=10.1080/03087298.1999.10443331 |url-access=subscription |access-date=26 October 2024}}</ref> then dried, sensitized in the silver bath, washed, irrigated with cyanine solution, and dried again. The back of the film is then brought into optical contact with a reflective surface. This originally was done by mounting the plate in a specialized holder with pure [[mercury (element)|mercury]] behind the film. When it is exposed in the camera through the glass side of the plate, the light rays which strike the transparent light-sensitive film are reflected back on themselves and, by interference, create [[standing wave]]s.<ref name=Eder668,670-672/> The standing waves cause exposure of the emulsion in diffraction patterns. The developed and fixated diffraction patterns constitute a [[Bragg diffraction|Bragg condition]] in which diffuse, white light is scattered in a specular fashion and undergoes constructive interference in accordance to Bragg's law.<ref>[[Bragg diffraction]]</ref> The result is an image having very similar colours as the original using a black and white photographic process.

For this method Lippmann won the [[Nobel Prize in Physics]] in 1908.<ref>{{cite web |url=http://nobelprize.org/nobel_prizes/physics/articles/biedermann/index.html |title=Lippmann's and Gabor's Revolutionary Approach to Imaging |website=nobelprize.org |url-status=dead |archive-url=https://web.archive.org/web/20060712011307/http://nobelprize.org/nobel_prizes/physics/articles/biedermann/index.html |archive-date=2006-07-12}} </ref>

The colour image can only be viewed in the reflection of a diffuse light source from the plate, making the [[field of view]] limited, and therefore not easily copied with conventional techniques. The method was very insensitive with the emulsions of the time and it never came into general use. Another reason Lippmann's process of colour photography did not succeed can be found in the invention of the [[Autochrome Lumière|autochrome plates]] by the [[Lumière brothers]].<ref name=Eder668,670-672/> A technique derived from the Lippmann technique has been proposed as a method of producing images which can easily be viewed, but not copied, for security purposes.<ref>{{Cite web |url=http://holowiki.nss.rpi.edu/wiki/Lippmann_Security |title=Optically Variable Device for Security Documents |last1=Bjelkhagen |first1=Hans |url-status=dead |archive-url=https://web.archive.org/web/20211021022005/http://holowiki.nss.rpi.edu/wiki/Lippmann_Security |archive-date=21 October 2021}}</ref>

==Gallery==
<gallery mode="packed">
File:Lippmann Still life.jpg|A still life by Lippmann
File:Lippmann Venice.jpg|[[Venice]] by Lippmann
File:Lippmann Saas Fee.jpg|[[Saas-Fee]] by Lippmann
File:Parrot photo made by Gabriel Lippmann in 1891.jpg|An 1899 interferential photograph of a stuffed parrot made by {{ill|Richard Neuhauss|de}}
File:Bouquet de Fleurs-laboratoire de physique de la faculté des sciences de Lille par Auguste Ponsot vers 1905.png|A 1906 interferential photograph by {{ill|Auguste Ponsot|fr|Auguste Ponsot (physicien)}}, Lippmann's student and colleague
</gallery>

==Other sources of Lippmann plates==
* The Kodak Spectroscopic Plate Type 649-F is specified with a resolving power of 2000 lines/mm.<ref>{{cite book |title=Kodak Plates and Films for Scientific Photography |year=1973 |publisher=Eastman Kodak Company |location=Rochester |isbn=0-87985-083-3 |page=13d}}</ref>
* A diffusion method for making silver bromide based holographic recording material was published.<ref>{{Citation |last=Blyth  |first=Jeff  |author2=Roger B. Millington  |author3=Andrew G. Mayes  |author4=Christopher R. Lowe  |title=A diffusion method for making silver bromide based holographic recording material  |work=Institute of Biotechnology, University of Cambridge, Tennis Court Road, Cambridge  |url=http://www.holoworld.com/holo/paper.html  |access-date=July 25, 2010  |url-status=dead  |archive-url=https://web.archive.org/web/20100128023001/http://www.holoworld.com/holo/paper.html  |archive-date=January 28, 2010}}</ref>

==Durable data storage utility==
Because the photographs are so durable, researchers have reworked Lippmann plates for use in [[Computer data storage|archival data storage]] to replace [[Hard disk drive|hard drives]].<ref name=IEEE>{{cite magazine |last1=Genkina |first1=Dina |date=24 October 2024 |title=A Picture Is Worth 4.6 Terabits: 19th-century photography technique employed in novel data storage method |url=https://spectrum.ieee.org/clark-johnson-profile |magazine=[[IEEE Spectrum]] |location=New York City |publisher=[[Institute of Electrical and Electronics Engineers]]}}</ref> Work began on the project after they were made aware data storage on the [[International Space Station]] requires daily maintenance because it can be damaged by [[cosmic rays]] and they recalled that silver halide would not be significantly affected by astroparticles (or even [[electromagnetic pulses]] from nuclear explosions). 150 standing-wave storage samples placed on the ISS during 2019 showed no signs of data degradation after exposure to cosmic rays for nine months.<ref name=IEEE/>

==See also==
* [[Photochromy]]
* [[Holography]]

==References==
{{reflist}}

==External links==
{{Commons category multi|Photographie interférentielle|Gabriel Lippmann}}
*[https://elysee.ch/en/exhibitions/gabriel-lippmann/ Exhibition of Gabriel Lippmann photochromes][https://actu.epfl.ch/news/lausanne-museum-unveils-the-secrets-of-the-first-c/ with associated press materials] at the [[Photo Élysée]] museum with technical assistance from [[École Polytechnique Fédérale de Lausanne|EPFL]] university
*[http://holowiki.org/wiki/Lippmann_Photography Wiki about Lippmann Process] by Holography Forum
*[https://holowiki.org/forum/viewforum.php?f=42 Forum about Lippmann Process] by Holography Forum
*[https://pod.univ-lille.fr/video/5671-les-plaques-precieuses-dauguste-ponsot/ Université de Lille video of photochrome examples] {{In lang|fr}}
*[https://asap.univ-lille.fr/patrimoine-appareils-scientifiques/publications-articles-temoignages Université de Lille article depicting Lippmann plates] {{In lang|fr}}
*[https://www.jonhilty.com/lippmann One set of instructions for making a Lippmann plate]

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{{DEFAULTSORT:Lippmann Plate}}
[[Category:Photographic processes]]

[[Category:Photographic processes dating from the 19th century]]
[[Category:Audiovisual introductions in 1891]]
[[Category:French inventions]]
[[Category:Luxembourgish inventions]]
[[Category:Alternative photographic processes]]
[[Category:19th century in art]]
[[Category:19th-century photography]]
[[Category:Computer data storage]]
[[Category:Computer storage devices]]
[[Category:Archival technology]]