Johann Heinrich Schulze or Schultz (12 May 1687 – 10 October 1744) was a German

Germany

Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 professor and polymath

Polymath

A polymath is a person whose expertise spans a significant number of different subject areas. In less formal terms, a polymath may simply be someone who is very knowledgeable...

 from Colbitz

Colbitz

Colbitz is a municipality in the Börde district in Saxony-Anhalt, Germany.Colbitz is well known for its "Colbitzer" beer and the Colbitz-Letzlinger Heide. The Colbitz-Letzlinger Heide is found in the northern area of Colbitz, but most parts of the heath landscape are used by the Bundeswehr - the...

 in the Duchy of Magdeburg

Duchy of Magdeburg

The Duchy of Magdeburg was a province of Brandenburg-Prussia from 1680 to 1701 and a province of the Kingdom of Prussia from 1701 to 1807. It replaced the Archbishopric of Magdeburg after its secularization by Brandenburg. The duchy's capitals were Magdeburg and Halle, while Burg was another...

.

History

Schulze studied medicine

Medicine

Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....

, chemistry

Chemistry

Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....

, philosophy

Philosophy

Philosophy is the study of general and fundamental problems, such as those connected with existence, knowledge, values, reason, mind, and language. Philosophy is distinguished from other ways of addressing such problems by its critical, generally systematic approach and its reliance on rational...

 and theology

Theology

Theology is the systematic and rational study of religion and its influences and of the nature of religious truths, or the learned profession acquired by completing specialized training in religious studies, usually at a university or school of divinity or seminary.-Definition:Augustine of Hippo...

 and became a professor

Professor

A professor is a scholarly teacher; the precise meaning of the term varies by country. Literally, professor derives from Latin as a "person who professes" being usually an expert in arts or sciences; a teacher of high rank...

 in Altdorf

University of Altdorf

The University of Altdorf was a university in Altdorf bei Nürnberg, a small town outside Nuremberg. It was founded in the late 16th century, received university privileges in 1622 and was closed in 1809 by Maximilian I Joseph of Bavaria....

 and Halle for anatomy

Anatomy

Anatomy is a branch of biology and medicine that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy , and plant anatomy...

 and several other subjects.

Notable discoveries

Schulze is best known for the discovery that certain silver

Silver

Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...

 salts, most notably silver chloride

Silver chloride

Silver chloride is a chemical compound with the chemical formula AgCl. This white crystalline solid is well known for its low solubility in water . Upon illumination or heating, silver chloride converts to silver , which is signalled by greyish or purplish coloration to some samples...

 and silver nitrate

Silver nitrate

Silver nitrate is an inorganic compound with chemical formula . This compound is a versatile precursor to many other silver compounds, such as those used in photography. It is far less sensitive to light than the halides...

, darken in the presence of light

Light

Light or visible light is electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight. Visible light has wavelength in a range from about 380 nanometres to about 740 nm, with a frequency range of about 405 THz to 790 THz...

, and for using those effects to capture temporary photographic images.
In an experiment conducted in 1724 he determined that a mixture of silver

Silver

Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...

 and chalk

Chalk

Chalk is a soft, white, porous sedimentary rock, a form of limestone composed of the mineral calcite. Calcite is calcium carbonate or CaCO3. It forms under reasonably deep marine conditions from the gradual accumulation of minute calcite plates shed from micro-organisms called coccolithophores....

 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

Light

Light or visible light is electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight. Visible light has wavelength in a range from about 380 nanometres to about 740 nm, with a frequency range of about 405 THz to 790 THz...

 - 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

Thomas Wedgwood (1771-1805)

Thomas Wedgwood , son of Josiah Wedgwood, the potter, was an early experimenter with Humphry Davy in photography.-Life:...

 and Sir Humphry Davy.