International Stereoscopic Union


A Glossary of Stereoscopic Terms

random-dot stereogram

A type of stereogram in which a three-dimensional image is formed by the fusing of apparently randomly-placed dots in a stereo pair: an effect first created manually by Herbert Mobbs of The Stereoscopic Society in the 1920s but scientifically developed, using computer-generated images, by Bela Julesz in the 1960s.


Short for Raumbildtechnik GmbH of Stuttgart/Germany, a company manufacturing stereo equipment mainly for the traditional R-mount size (41 x 101.6 mm), comprising cameras (derived from the siamesing of two individual cameras), projectors, mounts and viewers.

Realist format

The 5-perforation 35 mm slide format of 23 x 24 mm, originally created by the specification of the Stereo Realist (USA) camera, and subsequently adopted by many other manufacturers.

retinal rivalry (adv.)

Retinal rivalry is the simultaneous transmission of incompatible images from each eye.

R-mount, Rochwite

Name of the designer of the pioneering Stereo Realist camera from the 1950s, and its image-mounting system. A Rochwite mount (or R-mount) is one with overall dimensions of 41 x 101.6 mm (1 x 4 ins.), not more than 3 mm deep; adopted as the standard for traditionally-mounted stereo pairs of 35mm transparencies.


Tilting of the images through not holding the camera horizontally, causing one lens to be higher than the other at the picture-taking stage. If the tilting is not too severe, it may be possible to straighten both images when mounting but there will be a height error, however small, in part of the image.

A difference in the alignment of the two images in a stereogram caused by faulty mounting (see also twist).



International Stereoscopic Union
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