Editing Photogram (section)

===Prehistory===
The phenomenon of the shadow has long aroused human curiosity and inspired artistic representation, as recorded by [[Pliny the Elder]],<ref>Pliny the Elder, ''Natural History'', xxxv, 14</ref> and various forms of [[shadow play]] since the 1st millennium BCE.<ref name=chen25>Fan Pen Chen (2003), [https://www.jstor.org/stable/1179080 Shadow Theaters of the World], Asian Folklore Studies, Vol. 62, No. 1 (2003), pp. 25-64</ref><ref name=orr69>{{cite journal | last=Orr | first=Inge C. | title=Puppet Theatre in Asia | journal=Asian Folklore Studies | publisher=Nanzan University | volume=33 | issue=1 | year=1974 | doi=10.2307/1177504 | pages=69–84| jstor=1177504 }}</ref> The photogram, in essence, is a means by which the fall of light and shade on a surface may be automatically captured and preserved.<ref>{{Citation | author1=Stoichiță, Victor Ieronim | title=A short history of the shadow | date=August 1997 | publication-date=1997 | publisher=Reaktion Books | isbn=978-1-86189-000-9 | url=https://archive.org/details/shorthistoryofsh0000unse }}</ref><ref name=":1">{{Citation | author1=Barnes, Martin | author2=Neusüss, Floris Michael | author3=Cordier, Pierre | author4=Derges, Susan | author5=Fabian Miller, Garry | author6=Fuss, Adam | title=Shadow catchers : camera-less photography | year=2012 | publication-date=2012 |location=London, New York |publisher=Merrell / Victoria and Albert Museum | edition= Rev. and expanded | isbn=978-1-85894-592-7 }}</ref> To do so required a substance that would react to light. From the 17th century, [[Photochemistry|photochemical]] reactions were progressively observed or discovered in salts of silver, iron, uranium and chromium. In 1725, [[Johann Heinrich Schulze]] was the first to demonstrate a temporary photographic effect in [[Silver halide|silver salts]], confirmed by [[Carl Wilhelm Scheele|Carl Wilhhelm Scheele]] in 1777,<ref>{{Cite book|last=Eder|first=Josef Maria|url=https://www.worldcat.org/oclc/4005270|title=History of photography|publisher=Dover|year=1972|isbn=0-486-23586-6|edition=3rd|location=New York|pages=57–83|oclc=4005270}}</ref> who found that violet light caused the greatest reaction in [[silver chloride]]. [[Humphry Davy]] and [[Thomas Wedgwood (photographer)|Thomas Wedgewood]] reported<ref>Sir Humphry Davy (1802) 'An Account of a Method of Copying Paintings Upon Glass and of Making Profiles by the Agency of Light upon Nitrate of Silver, invented by T. Wedgwood Esq. In ''Journal of the Royal Institution''</ref> that they had produced temporary images from placing stencils/light sources on photo-sensitized materials, but had no means of fixing (making permanent) the images.<ref>{{Citation | author1=Hannavy, John | title=Encyclopedia of Nineteenth-Century Photography | publication-date=2005 | publisher=Taylor & Francis Ltd. | isbn=978-0-203-94178-2 }}</ref>

[[File:VanDyke-feather.jpg|thumb|upright|Photogram of a feather by [[Van Dyke brown (printing)|Van Dyke brown print]] copying technique.]]