A stereopticon is a

slide projector A slide projector is an optical device for projecting enlarged images of photographic slides onto a screen. Many projectors have mechanical arrangements to show a series of slides loaded into a special tray sequentially. 35 mm slide p ...

or relatively powerful "

magic lantern The magic lantern, also known by its Latin name , is an early type of image projector that uses pictures—paintings, prints, or photographs—on transparent plates (usually made of glass), one or more lens (optics), lenses, and a light source. ...

", which has two lenses, usually one above the other, and has mainly been used to project photographic images. These devices date back to the mid 19th century, and were a popular form of entertainment and education before the advent of moving pictures. Magic lanterns originally used rather weak light sources, like candles or oil lamps, that produced projections that were just large and strong enough to entertain small groups of people. During the 19th century stronger light sources, like

limelight Limelight (also known as Drummond light or calcium light)James R. Smith (2004). ''San Francisco's Lost Landmarks'', Quill Driver Books. is a non-electric type of stage lighting that was once used in theatres and music halls. An intense illum ...

, became available. For the "

dissolving views Dissolving views were a popular type of 19th century magic lantern show exhibiting the gradual transition from one projected image to another. The effect is similar to a dissolve in modern filmmaking. Typical examples had landscapes that dissolv ...

" lantern shows that were popularized by Henry Langdon Childe since the late 1830s, lanternists needed to be able to project two aligned pictures in the same spot on a screen, gradually dimming a first picture while revealing a second one. This could be done with two lanterns, but soon biunial lanterns (with two objectives placed one above the other) became common. William and Frederick Langenheim from Philadelphia introduced a photographic glass slide technology at the Crystal Palace Exhibition in London in 1851. For circa two centuries magic lanterns had been used to project painted images from glass slides, but the Langenheim brothers seem to have been the firsts to incorporate the relatively new medium of

photography Photography is the visual arts, art, application, and practice of creating images by recording light, either electronically by means of an image sensor, or chemically by means of a light-sensitive material such as photographic film. It is empl ...

(introduced in 1839). To enjoy the details of photographic slides optimally, the stronger lanterns were needed. By 1860 Massachusetts chemist and businessman John Fallon improved a large biunial lantern, imported from England, and named it 'stereopticon'. For a usual fee of ten cents, people could view realistic images of nature, history, and science themes. The two lenses are used to dissolve between images when projected. This "visual storytelling" with technology directly preceded the development of the first moving pictures. The term stereopticon has been widely misused to name a

stereoscope A stereoscope is a device for viewing a stereoscopy, stereoscopic pair of separate images, depicting left-eye and right-eye views of the same scene, as a single three-dimensional image. A typical stereoscope provides each eye with a lens that ...

. The stereopticon has not commonly been used for

three-dimensional In geometry, a three-dimensional space (3D space, 3-space or, rarely, tri-dimensional space) is a mathematical space in which three values (''coordinates'') are required to determine the position (geometry), position of a point (geometry), poi ...

images.

References

Further reading