Hermann Wilhelm Vogel (26 March 1834 – 17 December 1898) was a German photochemist and

photographer A photographer (the Greek φῶς (''phos''), meaning "light", and γραφή (''graphê''), meaning "drawing, writing", together meaning "drawing with light") is a person who makes photographs. Duties and types of photographers As in other ...

who discovered dye sensitization, which is of great importance to

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 ...

Academic career

After finishing school in Frankfurt (Oder), he studied at the Royal Industrial Institute of

Berlin Berlin ( , ) is the capital and List of cities in Germany by population, largest city of Germany by both area and population. Its 3.7 million inhabitants make it the European Union's List of cities in the European Union by population within ci ...

, earning his

Ph.D. A Doctor of Philosophy (PhD, Ph.D., or DPhil; Latin: or ') is the most common degree at the highest academic level awarded following a course of study. PhDs are awarded for programs across the whole breadth of academic fields. Because it is ...

with

Karl Friedrich August Rammelsberg Karl Friedrich August Rammelsberg (1 April 1813 – 28 December 1899) was a German mineralogist from Berlin, Prussia. Life After an apprenticeship in pharmacy, he studied chemistry and crystallography at the University of Berlin, where his inf ...

in 1863. Vogel's thesis, which was published in ''Poggendorffs Annalen'' , had the title: ''Über das Verhalten des Chlorsilbers, Bromsilbers und Iodsilbers im Licht und die Theorie der Photographie'' (Reactions of

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, ...

Silver Bromide Silver bromide (AgBr) is a soft, pale-yellow, water-insoluble salt well known (along with other silver halides) for its unusual sensitivity to light. This property has allowed silver halides to become the basis of modern photographic materials. A ...

and Silver Iodide with Light and the Theory of Photography). This marked the beginning of his research into the photographic process. From 1860 until 1865, he was an assistant in the mineralogical museum of the

University of Berlin Humboldt-Universität zu Berlin (german: Humboldt-Universität zu Berlin, abbreviated HU Berlin) is a German public research university in the central borough of Mitte in Berlin. It was established by Frederick William III on the initiative ...

, and from 1884 was director of the photo-technical laboratory of the Technical Institute there. From 1864 he was a professor at Berlin's

Technische Hochschule A ''Technische Hochschule'' (, plural: ''Technische Hochschulen'', abbreviated ''TH'') is a type of university focusing on engineering sciences in Germany. Previously, it also existed in Austria, Switzerland, the Netherlands (), and Finland (, ). ...

(from 1879, the Technical University of Berlin), where he introduced photography as a field of study.Grove Art Online, Vogel, Hermann Wilhelm
/ref>

Dye sensitization

In 1873 Vogel discovered dye sensitization, a pivotal contribution to the progress of

. The

photographic emulsion Photographic emulsion is a light-sensitive colloid used in film-based photography. Most commonly, in silver-gelatin photography, it consists of silver halide crystals dispersed in gelatin. The emulsion is usually coated onto a substrate of glas ...

s in use at that time were sensitive to blue, violet and ultraviolet light, but only slightly sensitive to green and practically insensitive to the rest of the

spectrum A spectrum (plural ''spectra'' or ''spectrums'') is a condition that is not limited to a specific set of values but can vary, without gaps, across a continuum. The word was first used scientifically in optics to describe the rainbow of colors ...

. While trying out some factory-made

collodion Collodion is a flammable, syrupy solution of nitrocellulose in ether and alcohol. There are two basic types: flexible and non-flexible. The flexible type is often used as a surgical dressing or to hold dressings in place. When painted on the skin, ...

bromide A bromide ion is the negatively charged form (Br−) of the element bromine, a member of the halogens group on the periodic table. Most bromides are colorless. Bromides have many practical roles, being found in anticonvulsants, flame-retardant ...

dry plate Dry plate, also known as gelatin process, is an improved type of photographic plate. It was invented by Dr. Richard L. Maddox in 1871 and had become so widely adopted by 1879 that the first dry plate factory had been established. With much of ...

s from England, Vogel was amazed to find that they were more sensitive to green than to blue. He sought the cause and his experiments indicated that this sensitivity was due to a yellow substance in the emulsion, apparently included as an anti-halation agent. Rinsing it out with alcohol removed the unusual sensitivity to green. He then tried adding small amounts of various

aniline Aniline is an organic compound with the formula C6 H5 NH2. Consisting of a phenyl group attached to an amino group, aniline is the simplest aromatic amine. It is an industrially significant commodity chemical, as well as a versatile starti ...

dyes to freshly prepared emulsions and found several dyes which added sensitivity to various parts of the spectrum, closely corresponding to

wavelengths In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats. It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, tr ...

of light the dyes absorbed. Vogel was able to add sensitivity to green, yellow, orange and even red. This made photography much more useful to science, allowed a more satisfactory rendering of colored subjects into

black-and-white Black-and-white (B&W or B/W) images combine black and white in a continuous spectrum, producing a range of shades of grey. Media The history of various visual media began with black and white, and as technology improved, altered to color. ...

, and brought actual color photography into the realm of the practical. In the early 1890s, Vogel's son Ernst assisted German-American photographer William Kurtz in applying dye sensitization and three-color photography to halftone printing, so that full-color prints could be economically mass-produced with a printing press.

Other activities

In addition to his work as a photographic technical innovator, Vogel taught Alfred Stieglitz between 1882 and 1886. He participated in at least two photographic expeditions to

Egypt Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia via a land bridge formed by the Sinai Peninsula. It is bordered by the Medit ...

as well as others to

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical ...

and possibly

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...

. Vogel founded the periodical ''Photographische Mittheilungen'' in 1864 and served as its publisher until his death. His silver tester,

photometer A photometer is an instrument that measures the strength of electromagnetic radiation in the range from ultraviolet to infrared and including the visible spectrum. Most photometers convert light into an electric current using a photoresistor, ...

for pigment printing and heliotype printing, and universal

spectroscope An optical spectrometer (spectrophotometer, spectrograph or spectroscope) is an instrument used to measure properties of light over a specific portion of the electromagnetic spectrum, typically used in spectroscopic analysis to identify mate ...

were introduced into general use. He visited the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

in 1870 and 1883.

Publications

* ''Lehrbuch der Photographie'' (Third edition, Berlin 1878) * ''Praktische Spektralanalyse irdischer Stoffe'' (Second edition, Berlin 1888) * ''Die chemischen Wirkungen des Lichts und die Photographie'' (Second edition, Leipzig 1883) * ''Die Photographie farbiger Gegenstände in den richtigen Tonverhältnissen'' (Berlin 1885) * ''Vom Indischen Ozean bis zum Goldland'' Reisebeobachtungen (Berlin 1878) * ''Lichtbilder nach der Natur'' (Berlin 1879) * ''The Chemistry of Light and Photography, in Their Application to Art, Science, and Industry'' (New and thoroughly revised edition, D. Appleton, New York 1889) * ''Über das Spiritistentreiben'' (Berlin 1880)

Notes

References

External links

* Herman Wilhelm Vogel (1875
''The chemistry of light and photography''
-

Linda Hall Library The Linda Hall Library is a privately endowed American library of science, engineering and technology located in Kansas City, Missouri, sitting "majestically on a urban arboretum." It is the "largest independently funded public library of scien ...

*
A Simple Test For Carbonic Oxide
,

Scientific American ''Scientific American'', informally abbreviated ''SciAm'' or sometimes ''SA'', is an American popular science magazine. Many famous scientists, including Albert Einstein and Nikola Tesla, have contributed articles to it. In print since 1845, it ...

article on carbon monoxide detection developed by Vogel, 23 June 1877, p. 386 {{DEFAULTSORT:Vogel, Hermann Wilhelm 1834 births 1898 deaths People from Doberlug-Kirchhain 19th-century German chemists Photographers from Brandenburg People from the Province of Brandenburg Humboldt University of Berlin alumni Technical University of Berlin faculty