Johann Heinrich Schulze or
Schultz (
12 May 1687 –
10 October 1744) was a
German professor and
polymath from
Colbitz in the
Duchy of Magdeburg.
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 the discovery that certain
silver salts, most notably
silver chloride and
silver nitrate, darken in the presence of
light. 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. The first permanent photograph based on this principle was made in 1826 by
Joseph Nicéphore Niépce in
Paris. Other researchers in this field included
Thomas Wedgwood and
Sir Humphry Davy.
See also
References
