Johann Heinrich Schulze

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Johann Heinrich Schulze
Johann Heinrich Schulze.gif
Johann Heinrich Schulze
Born12 May 1687
Colbitz, Duchy of Magdeburg
Died10 October 1744(1744-10-10) (aged 57)
NationalityGerman
Alma materAltdorf
Known forexperiments with silver nitrate
Scientific career
InstitutionsAltdorf
Halle
Influencedthe invention of photography

Johann Heinrich Schulze (12 May 1687 – 10 October 1744) was a German professor and polymath.

History[]

Schulze studied medicine, chemistry, philosophy and theology and became a professor in Altdorf and Halle for anatomy and several other subjects.

Notable discoveries[]

Schulze is best known for his discovery that the darkening in sunlight of various substances mixed with silver nitrate is due to the light, not the heat as other experimenters believed, and for using the phenomenon to temporarily capture shadows.[1]

Schulze's experiments with silver nitrate were undertaken in about 1717.[2] He found that a slurry of chalk and nitric acid into which some silver had been dissolved was darkened by sunlight, but not by exposure to the heat from a fire. To provide an interesting demonstration of its darkening by light, he applied stencils of words to a bottle filled with the mixture and put it in direct sunlight, which produced copies of the text in dark characters on the surface of the contents. The impressions persisted until they were erased by shaking the bottle or until overall exposure to light obliterated them. Because they were produced by the action of light, an extremely broad and literal definition of what a photograph is may allow even these fluid, ephemeral sun printings to qualify, and on that basis many German sources credit Schulze as the inventor of photography.[3][4]

Though Schulze's work did not provide a means of permanently preserving an image, it did provide a foundation for later efforts toward that end. Thomas Wedgwood and Humphry Davy produced more substantial but still impermanent shadow images on coated paper and leather around the year 1800. Nicéphore Niépce succeeded in photographing camera images on paper coated with silver chloride in 1816 but he, too, could not make his results light-fast.[5] The first permanent camera photograph of this type was made in 1835 by Henry Fox Talbot.[1]

Works[]

See also[]

References[]

  1. ^ Jump up to: a b Leslie Stroebel and Richard D. Zakia (1993). The Focal encyclopedia of photography (3rd ed.). Focal Press. p. 6. ISBN 978-0-240-51417-8.
  2. ^ This date is commonly misreported as 1725 or 1727, an error deriving from the belief that a 1727 publication of Schulze's account of experiments he says he undertook about two years earlier is the original source. In fact, it is a reprint of a 1719 publication and the date of the experiments is therefore circa 1717. The dated contents page of the true original can be seen here (retrieved 2015-02-21)
  3. ^ Susan Watt (2003). Silver. Marshall Cavendish. pp. 21–. ISBN 978-0-7614-1464-3. Retrieved 28 July 2013. ... But the first person to use this property to produce a photographic image was German physicist Johann Heinrich Schulze. In 1727, Schulze made a paste of silver nitrate and chalk, placed the mixture in a glass bottle, and wrapped the bottle in ...
  4. ^ Litchfield, Richard Buckley (1903). Tom Wedgwood, the First Photographer, etc., London, Duckworth and Co. Out of copyright and available free at archive.org. In Appendix A (pp. 217-227), Litchfield evaluates assertions that Schulze's experiments should be called photography and includes a complete English translation (from the original Latin) of Schulze's 1719 account of them as reprinted in 1727.
  5. ^ Niépce House Museum: Invention of Photography: 1816-1818, Niépce's first tries[permanent dead link] (retrieved 2012-11-01)
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