Bitumen of Judea
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{{Short description|Type of naturally occurring asphalt}}
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Bitumen of Judea is a naturally occurring asphalt used since antiquity as a wood colorant, and in early photography as a light-sensitive coating.
Wood coloration usage
Bitumen of Judea may be used as a colorant for wood for an aged, natural and rustic appearance. It is soluble in turpentine and some other terpenes, and can be combined with oils, waxes, varnishes and glazes.
Light-sensitive properties
It is a light-sensitive material in what is accepted to be the first complete photographic process, i.e., one capable of producing durable light-fast results.{{cite book|last1=Newhall|first1=Beaumont|title=The History of Photography: from 1839 to the present|date=1982|publisher=Museum of Modern Art|location=New York|isbn=978-0870703812|edition=5th|url-access=registration|url=https://archive.org/details/historyofphotogr0000newh}} The technique was developed by French scientist and inventor Nicéphore Niépce in the 1820s. In 1826 or 1827,Eder, Josef Maria. History of Photography. pp. 203–206. he applied a thin coating of the tar-like material to a pewter plate and took a picture of parts of the buildings and surrounding countryside of his estate, producing what is usually described as the first photograph. It is considered to be the oldest known surviving photograph made in a camera. The plate was exposed in the camera for at least eight hours.{{cite web|title=The First Photograph|url=http://www.hrc.utexas.edu/exhibitions/permanent/firstphotograph/process/#top|website=Harry Ransom Center, University of Texas at Austin|accessdate=26 February 2016}}
The bitumen, initially soluble in spirits and oils, was hardened and made insoluble (probably polymerized){{synthesis-inline|date=January 2016}} in the brightest areas of the image. The unhardened part was then rinsed away with a solvent.[http://www.niepce.org/pagus/pagus-inv.html Niépce Museum history pages] {{webarchive |url=https://web.archive.org/web/20070803222723/http://www.niepce.org/pagus/pagus-inv.html |date=August 3, 2007 }}Hirsch, Robert. Seizing the Light: A History of Photography. New York: McGraw-Hill, 2000. Print.
Niépce's primary objective was not a photoengraving or photolithography process, but rather a photo-etching process, since engraving requires the intervention of a physical rather than chemical process and lithography involves a grease and water resistance process. However, Niépce's famous image of Pope Pius VI was produced first by photo-etching and then "improved" by hand engraving. Bitumen, superbly resistant to strong acids, was in fact later widely used as a photoresist in making printing plates for mechanical printing processes.{{Citation needed|reason=content of this paragraph is not contained in Newhall ref, which is also incorrectly cited|date=January 2016}} The surface of a zinc or other metal plate was coated, exposed, developed with a solvent that laid bare the unexposed areas, then etched in an acid bath, producing the required surface relief.Beaumont Newhall, "The History of Photography," 2001, p 14. {{ISBN|0-87070-381-1}}{{failed verification|reason=Info on photolithography is not in Newhall reference, which is incorrectly cited - Newhall was last published in 1982|date=January 2016}}