Carl Pulfrich

Carl P. Pulfrich (September 24, 1858 in Burscheid, Rhine Province, Kingdom of Prussia – August 12, 1927 in Baltic Sea, drowned when his canoe capsized) was a German physicist, noted for advancements in optics made as a researcher for the Carl Zeiss company in Jena around 1880, and for documenting the Pulfrich effect, a psycho-optical phenomenon that can be used to create a type of 3-D visual effect. Carl Pulfrich was the brother-in-law of Heinrich Hertz.

Advances in optics Pulfrich was employed to develop stereoscopy from being pure entertainment to a powerful quantitative technique. His apparatus to measure distances stereoscopically was first presented in Munich in 1899. This was further developed to a stereo-comparator which was presented in Hamburg in 1901. Stereoscopy was used for topographic mapping, astronomy and oceanography because it enabled the measurement of elevation by simple trigonometry. He pioneered the use of aerial photography surveys.

He introduced in 1909 a "Vacation Course in Stereophotogrammetry", that gave rise to the annual "Photogrammetry Week" running for more than a century. Leica Geosystems sponsors the "Carl Pulfrich Award", to honour advancements in the fields of photogrammetry, remote sensing, and earth imaging.

Pulfrich had realised that people in whom visual function differed between both eyes perceived the stereo-effect:

Pulfrich's comment implies a list of diseases in which the stereo-effect can occur. He wondered why the stereo-effect was not noted earlier because of the abundance of swinging clock pendulums: “Wenn man bedenkt mit welch einfachen Mitteln die Erscheinung der kreisenden Marke hervorgerufen werden kann, so kann man sich nur darüber wundern, dass sie anscheinend nicht schon früher einmal beobachtet worden ist, wozu doch jeder Uhrenladen die Gelegenheit bietet.”[If one considers the simple means used to produce the phenomenon of the circulating pointer, one wonders why this observation has not been made earlier, particularly as every shop selling clocks offers this opportunity.] |Carl P. Pulfrich