Johann Heinrich Schulze
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| Johann Heinrich Schulze | |
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 Johann Heinrich Schulze
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| Born | 12 May 1687 |
| Died | 10 October 1744 (aged 57) |
| Nationality | German |
| Institutions | Altdorf Halle |
| Alma mater | Altdorf |
| Known for | silver chloride and silver nitrate darken in the presence of light |
| Influenced | Joseph Nicéphore Niépce |
Johann Heinrich Schulze or Schultz (12 May 1687 – 10 October 1744) was a German professor and polymath from Colbitz in the Duchy of Magdeburg.
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[edit] History
Schulze studied medicine, chemistry, philosophy and theology and became a professor in Altdorf and Halle for anatomy and several other subjects.
[edit] Notable discoveries
Schulze is best known for the discovery that certain silver salts, most notably silver chloride and silver nitrate, darken in the presence of light, and for using those effects to capture temporary photographic images.[1] In an experiment conducted in 1724 he determined that a mixture of silver and chalk reflects less light than untarnished silver. Though his discovery did not provide the means of preserving an image - the silver salts continued to darken unless protected from light - it did provide the foundation for further work in fixing images.
Joseph Nicéphore Niépce made partially fixed images using silver salts in 1816; the first permanent photograph based on this principle was made shortly after by William Henry Fox Talbot. Other researchers in this field included Thomas Wedgwood and Sir Humphry Davy.[1]
[edit] See also
[edit] References
- ^ a b Leslie Stroebel and Richard D. Zakia (1993). The Focal encyclopedia of photography (3rd ed.). Focal Press. p. 6. ISBN 9780240514178. http://books.google.com/books?id=CU7-2ZLGFpYC&pg=PA6.
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