Josef Maria Eder

Josef Maria Eder (16 March 1855 – 18 October 1944) was an Austrian chemist who specialized in the chemistry of photography, and who wrote a comprehensive early history of the technical development of chemical photography.¹

Life and work

Eder was born in Krems an der Donau in 1855. He studied chemistry, physics and mathematics at the Vienna University of Technology and at the University of Vienna. In 1876, he received his PhD and in 1879, after his habilitation, became lecturer at the Vienna University of Technology.

Eder's research then focused on the chemistry of photography. After spending some time at the Staatliche Gewerbeschule Vienna, he became lecturer at the Höhere Gewerbeschule Vienna. This change improved his capacity to undertake research. In the following years, Eder developed a sensitized gelatin silver process. Orthochromatic photographic plates, in combination with a color filter counter-acting the plates' inhomogeneous sensitivity to light of different wavelengths, yielded black and white images showing all colors of the light in their true brightness.

Eder was a professor at the Vienna University of Technology from 1892 to 1925²³⁴ where one of the engineering students was the Hungarian André Steiner whom Eder encouraged to take up photography.⁵ Eder introduced scientific method into the development of photographic processes. In particular, he used spectroscopy and invented several new instruments including the "Eder-Hecht neutral wedge " (with (1896–1960)), also the "mercury oxalate photometer" which was a chemical to measure the intensity of . After the effect of on photographic material was published, Eder did research to improve the sensitivity of photographic material to X-rays.