Carl Pulfrich


Carl P. Pulfrich 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.

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 geography, astronomy and oceanography because everything could be done quickly and precisely. He pioneered the use of stereoscopy from planes for topographic purposes.
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:

Pulfrich refractometer

A Pulfrich refractometer measures refractive index of a sample by measuring the critical angle of the sample with a well characterized prism. Pulfrich and Max Wolz invented it at the Zeiss factory.