EMTS Centennial Exhibit: Gallery: Stereoscopic

Stereoscopic Materials and Viewmasters

These days most folks don't know what you're talkinga bout when you say "stereoscopic," but some folks will have a gleam of recognition if you say "Viewmaster." The technology in both is basically the same, however all Viewmaster reels are stereoscopic images, but not all stereoscopic images are Viewmaster reels, as we shall see.
Stereoscopic materials are based on the discovery that if you take two pictures of the same thing from a distance slightly apart (the same distance as that between the average person's eyes), it is possible to view them in a way that gives them a three-dimensional appearance. This is a gross over-simplification of what is involved, but gives you the idea of why they were particularly valuable. This is also why, even though they are used rarely nowadays, they have never been completely replaced -- there is nothing else out there that is so portable and easy to use that gives that 3D information. This has been particularly vaulable in studies of the nervous system when one needs to see which nerves lies above or behind another, but especially in opthalmology and views of the retina.
Originally stereoscopic images were printed side by side on heavy cardboard. They would be viewed by placing a divider between your eyes and positioning your eyes the magical distance away from the divided images for them to leap into focus. Low tech, but effective. The use of stereoscopic images progressed through a variety of personal viewers, and much to my surprise, they even had equipment to project the Viewmaster reels to an audience. Just as people now do when viewing 3D information in a group setting, the audience would wear the little cardboard glasses with different colored lenses.

Original Print Stereoscopic "Slide" (Click to blow up this image to a size that, if printed, you can actually test out with a piece of cardboard between your eyes)	A Viewmaster Reel
	The Cover of an Instruction Booklet for Using a Regular Viewmaster
A Compact Viewmaster	Stereoscopic Retina Images
The Cover of an Instruction Booklet for Using a Compact Viewmaster	Catalog of Viewmaster Hardware and Peripherals, Including Projection Equipment