Editing Thomas Johann Seebeck (section)

==Precursors to color photography==

In 1810, at [[Jena]], Seebeck described the action of light on silver chloride sensitised paper (a technique used by [[Johann Wilhelm Ritter|Johann Ritter]]).<ref name=":2">{{Cite book |first=John |last=Hannavy |url=http://worldcat.org/oclc/1019889278 |title=Encyclopedia of nineteenth-century photography |date=2008 |publisher=Taylor & Francis Group |isbn=978-0-415-97235-2 |oclc=1019889278}}</ref><ref>{{Cite book |last=Eder |first=Josef Maria, Epstean, Edward |url=https://doi.org/10.7312/eder91430 |title=History of Photography |date=1945 |doi=10.7312/eder91430 |isbn=978-0-231-88370-2 |oclc=1104874591}}</ref> He observed that the exposed chemical would sometimes take on an approximate, pale version of the color of the solar spectrum as projected from a prism to which it had been exposed, and also reported the action of light for a wavelengths beyond the violet end of the spectrum.<ref>{{cite EB1911|wstitle= Photochemistry |volume= 21 | pages = 484–485 }}</ref> Seebeck reported that violet produced red-brown;  blue in the blue segment, which spread into the green; he got black or yellowish in yellow light; and  red produced rose red or hortensia red.<ref name=":2" /> The experiment could not be preserved because he could not fix the silver chloride to prevent its further reaction to light, though Hannavy reports that "in a spectrum attributed to Seebeck in a private collection the purple and violet currently remain visible," albeit weakly.<ref name=":2" /> He corresponded with [[Johann Wolfgang von Goethe|J. W. Goethe]] who was writing on the ''[[Theory of Colours]]'' (Zur Farbenlehre) and who included Seebeck's discovery as an appendix.<ref>{{cite book |author=Johann Wolfgang von Goethe |url=https://theoryofcolor.org/Theory+of+Colors |title=Theory of Colours |year=1810}}</ref>