The University of Sydney - Sydney University Museums

2:1 A Short Explanation

A stereo photograph consists of two photographs, one taken as the left eye sees a view and another slightly offset as the right eye would see the same view. These photographs are mounted on a card which is then placed into a stereoscopic viewer. The stereoscope allows the brain to superimpose the two images, imitating the three-dimensional stereovision of the human eye.

Stereo photographs are essentially the combination of two inventions of the 1830s. Sir Charles Wheatstone announced the first of these in 1838, an optical viewer using mirrors that could combine two separate images representing the slight difference in view between the left and right eyes to produce a three-dimensional effect. The second occurred in 1839 when Louis Daguerre and Henry Fox Talbot announced to the world two different photographic processes, the ‘daguerreotype’ and the ‘talbotype’ or ‘calotype’ respectively.

In the 1840s Sir Charles Wheatstone began experimenting with Talbot’s process, which enabled him to place two slightly offset photographic images in his viewer. The success of these experiments inspired a Scotsman, Sir David Brewster, to announce in 1849 his modification of the stereoscope using lenses and thus known as a lenticular stereoscope. It was Brewster’s stereoscope which defined the standard for the format and was popularised from the early 1850s.