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.

RBT

Short for Raumbildtechnik GmbH of Stuttgart, a company manufacturing stereo equipment mainly for the traditional R-mount size (41x101.6 mm), comprising cameras (derived from the siamesing of two individual cameras), projectors, mounts and viewers.

Realist format

The 5-perforation 35mm slide format of 23x24mm, originally created by the specification of the Stereo Realist (USA) camera, and subsequently adopted by many other manufacturers.

retinal rivalry (adv.)

Use of a longer than normal stereo base in order to achieve the effect of enhanced stereo depth and reduced scale of a scene; it produces an effect known as Lilliputism because of the miniaturisation of the subject matter which appears as a result. Often used in order to reveal depth discrimination in architectural and geological features. The converse of hypostereo.

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.

rotation

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).