Siegfried Rösch

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Siegfried Rösch

Siegfried Rösch (born June 15, 1899 in Ludwigshafen am Rhein , † January 22, 1984 in Wetzlar ) was a German mineralogist and color scientist who became known for the color body of the CIE system . He also worked as a genealogist.


After graduating from high school in Heidelberg in 1917, he was a soldier in the First World War and was injured in a poison gas attack . He then studied mineralogy in Munich from 1920 to 1926 , with Victor Mordechai Goldschmidt in Heidelberg and with Friedrich Rinne in Leipzig. The study and subsequent work as a lecturer he concluded after his 1926 carried Promotion to Dr. rer. nat. in 1929 with his habilitation in color theory in mineralogy .

From 1933 he was a research assistant at the Leitz company in Wetzlar , where he was involved in the development of the famous Leica 35mm camera . In 1937 he became a private lecturer and was finally professor of mineralogy at the University of Giessen from 1942 to 1965 .


During his habilitation and the study of color theory in Dresden in 1927, he had contact with Robert Luther's thoughts on so-called optimal colors , which were suggested by Wilhelm Ostwald . From this he developed the concept of relative brightness .

A color measuring device, the optimal colorimeter, also emerged from this work. The development took place at the Institute for Mineralogy at the University of Leipzig . During this time (late 1920s) he worked with Carl Pulfrich in Jena and Erwin Schrödinger in Berlin. In doing so, he developed the colorimetric Rösch key figures and, in 1928, offered the matching color body according to Rösch for the development of the CIE system , in which the xy chromaticity level is combined with the relative brightness. This color body contains all realizable body colors ; that not all can be displayed on every device is due to the limited device color space .

In 1931 he developed the spectral integrator for integrating spectra in Leipzig . Further device developments were added in Wetzlar: the three-color mixer and a polarization color measuring device. His main field was the application of color theory for mineralogy, crystallography and related to the determination of precious stones . Due to his habilitation, he was active in color measurement in addition to his specialist field of mineralogy and petrography . He is a co-founder of the Color Standards Committee (FNF) and in this function was co-editor of the magazine “Farbe”. In addition to his main areas, he also dealt with mathematics , sundials , archiving , photography , harmony and genealogy .

Alfred Hickethier asked Rösch for help with the publication of the Hickethier Large Color Code . While working together on a color catalog , Hickethier passed away. Rösch then continued work on the work and took over the editing, posthumously in 1972.

As a genealogist, Rösch dealt with Goethe's relatives, the Buff family (Werther's "Lotte"), the descendants of Charlemagne and especially with mathematical problems in connection with ancestral decline and relatives marriages (multiple affinities ).


Works (selection)

  • Siegfried Rösch: The identification of the colors . In: Physikalische Zeitschrift 29, 1928, pp. 83-91
  • Siegfried Rösch (ed.): The great color order Hickethier . Otto Meier, Ravensburg 1972
  • Siegfried Rösch: About the degree of relationship . In: Familie und Volk 1957, No. 2, pp. 313-317
  • Siegfried Rösch: Basics of a quantitative genealogy . = Internship for genealogists , volume 31, Degener, Neustadt / Aisch 1955 (also in Goethe's relatives )
  • Siegfried Rösch: Goethe's relatives. Attempt a total kinship table with thoughts on their theory . Degener, Neustadt / Aisch 1956
  • Siegfried Rösch: Caroli Magni Progenies, Pars I , Degener, Neustadt / Aisch 1977


  • GA Agoston: Color Theory and Its Application in Art and Design . Heidelberg 1979
  • Manfred Richter: Introduction to colorimetry . Walter deGruyter, Berlin 1976
  • FW Euler : Professor Dr. Siegfried Rösch . In: Archives for Family Research 1984, Issue 93, pp. 390–391
  • FW: In memoriam Siegfried Rösch . In: Der Herold 27, 1984
  • Wolfgang Ollrog: Professor Siegfried Rösch 80 years old . In: Norddeutsche Familienkunde 1979, Heft 2, pp. 360–361
  • Wetzlarer Goethe Gesellschaft eV and Buff-Kestner Family Association (ed.): Siegfried Rösch 1899–1984 , 1984

Web links

Individual evidence

  1. ^ Siegfried Rösch: Presentation of the theory of colors for the purposes of mineralogy
  2. ^ Siegfried Rösch: The marking of the colors . In: Physikalische Zeitschrift , Volume 29, Pages 83–91 (1928)
  3. Manfred Richter: Introduction to colorimetry . Berlin 1976
  4. Aemilius Müller : The three-color cube 1000 for the graphic industry. Winterthur 1951.