Adolf Miethe (1862-1927)

On 25 April 1862, Adolf Miethe was born in Potsdam, where his father was a city councillor. Even as a child he was interested in the new science of photography and in optical instruments. He left home to study, first in Berlin, where he studied Physics, Astronomy and Chemistry, before going to Göttingen, where he was conferred a PhD for his work "Zur Actinometrie photographisch-astronomischer Fixsternaufnahmen" (On the actinometry of photographic astronomical images of fixed stars") in 1889. He had previously worked as an assistant at Potsdam's Astrophysical Observatory and (together with a friend) invented magnesium flash lighting in 1887.

From 1889 onwards he was employed as a member of scientific staff at the E. Hartnack microscope factory in Potsdam, where he became one of the first to design aplanatic lenses using Jena glass, calling them "Anastigmate". Following Hartnack's death he held a similar post at Schulze & Bartels in Rathenow, a centre of the optical industry, where he performed calculations for and designed opera glasses, marine telescopes and telescopic sights, and where he was also able to independently develop a telephoto lens. In 1894 he went to Voigtländer & Sohn in Braunschweig. Following his initial involvement in the design of terrestrial binocular telescopes and telescopic sights, he was made one of the two directors of the firm after it had become a joint-stock company.

In 1899 Miethe was called to the Technische Hochschule in Charlottenburg, Berlin, where his predecessor Hermann Wilhelm Vogel (1834-1898) had held the first chair for Photochemistry, Photography and Spectroanalysis since 1873 (at the Gewerbeakademie - Commercial Academy). Miethe expanded the photochemical laboratory there, arranging for a photographic observatory to be annexed in 1909. He also increased the amount of photomechanical reproduction technology available there by adding a test printing department. In 1921 he played a vital role in founding a test and research institute for cinematography, thus introducing the discipline to the TH Berlin.

One of Miethe's goals was colour photography as a three-colour synthesis using three monochrome photo-diapositives. After discovering the red-sensitising characteristics of the isocyanines, he used " ethyl red" for panchromatic dry plates and was able to introduce trichromatographic photography to the world in 1909. Always interested in linking photography and astronomy, he studied polarisation effects and the ultraviolet end of the solar spectrum on an 1908 expedition to Upper Egypt. In 1910 he accompanied the Zeppelin expedition to Spitzbergen and led the solar eclipse expedition to northern Norway in 1914.

Miethe's chemical activities included the synthetic preparation of corundum and spinels used in the jewellery industry. In 1904, he succeeded in synthesising rubies for industrial purposes for applications such as bearings in clocks, watches and in precision instruments. From 1924 on, he was involved in attempts to make mercury decompose under the effects of electrical discharges in order to create gold. However, other chemists were able to show that the (proven) small amounts of gold present were merely impurities.

Miethe published a number of periodicals on photography, also writing 13 books and more than 90 essays - both for scientific experts and the interested public. Artistically gifted, he illustrated his travel stories not just with photographs, but also with his own drawings and watercolours. Miethe died of cardiac insufficiency in Berlin on 5 May 1927, after an operation following an accident.

Lit.: NDB (additional literature there)

[B. E.]