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

polymath A polymath ( el, πολυμαθής, , "having learned much"; la, homo universalis, "universal human") is an individual whose knowledge spans a substantial number of subjects, known to draw on complex bodies of knowledge to solve specific pro ...

History

Schulze studied

medicine Medicine is the science and practice of caring for a patient, managing the diagnosis, prognosis, prevention, treatment, palliation of their injury or disease, and promoting their health. Medicine encompasses a variety of health care pr ...

, chemistry, philosophy and

theology Theology is the systematic study of the nature of the divine and, more broadly, of religious belief. It is taught as an academic discipline, typically in universities and seminaries. It occupies itself with the unique content of analyzing the ...

and became a

professor Professor (commonly abbreviated as Prof.) is an academic rank at universities and other post-secondary education and research institutions in most countries. Literally, ''professor'' derives from Latin as a "person who professes". Professors ...

in Altdorf and Halle for

anatomy Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having it ...

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 Silver nitrate is an inorganic compound with chemical formula . It 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. It was once called ''lunar causti ...

is due to the

light Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 te ...

, not the heat as other experimenters believed, and for using the phenomenon to temporarily capture shadows. Schulze's experiments with silver nitrate were undertaken in about 1717. He found that a slurry of

chalk Chalk is a soft, white, porous, sedimentary carbonate rock. It is a form of limestone composed of the mineral calcite and originally formed deep under the sea by the compression of microscopic plankton that had settled to the sea floor. Ch ...

and

nitric acid Nitric acid is the inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but older samples tend to be yellow cast due to decomposition into oxides of nitrogen. Most commercially available nitri ...

into which some

silver Silver is a chemical element with the symbol Ag (from the Latin ', derived from the Proto-Indo-European ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical ...

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 as such, and on that basis many German sources credit Schulze as the inventor of

photography Photography is the art, application, and practice of creating durable images by recording light, either electronically by means of an image sensor, or chemically by means of a light-sensitive material such as photographic film. It is employe ...

. 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 Sir Humphry Davy, 1st Baronet, (17 December 177829 May 1829) was a British chemist and inventor who invented the Davy lamp and a very early form of arc lamp. He is also remembered for isolating, by using electricity, several elements for t ...

produced more substantial but still impermanent shadow images on coated paper and leather around the year 1800.

Nicéphore Niépce Joseph Nicéphore Niépce (; 7 March 1765 – 5 July 1833), commonly known or referred to simply as Nicéphore Niépce, was a French inventor, usually credited with the invention of photography. Niépce developed heliography, a technique he us ...

succeeded in photographing

camera A camera is an optical instrument that can capture an image. Most cameras can capture 2D images, with some more advanced models being able to capture 3D images. At a basic level, most cameras consist of sealed boxes (the camera body), with a ...

images on paper coated with

silver chloride Silver chloride is a chemical compound with the chemical formula Ag Cl. This white crystalline solid is well known for its low solubility in water (this behavior being reminiscent of the chlorides of Tl+ and Pb2+). Upon illumination or heating, ...

in 1816 but he, too, could not make his results light-fast.Niépce House Museum: Invention of Photography: 1816-1818, Niépce's first tries
(retrieved 2012-11-01) The first permanent camera photograph of this type was made in 1835 by Henry Fox Talbot.

Works

* ''Abhandlung von der Stein-Chur durch innerliche Artzeneyen überhaupt und insonderheit von der neulich bekannt gewordenen Englischen'' . Franckfurt, 174
Digital edition
by the University and State Library Düsseldorf * ''Chemische Versuche'' . Waysenhaus, Halle 174
Digital edition
by the University and State Library Düsseldorf

References

{{DEFAULTSORT:Schulze, Johann Heinrich 1687 births 1744 deaths People from the Duchy of Magdeburg Photography in Germany Precursors of photography University of Altdorf faculty University of Halle alumni University of Halle faculty