Stereographs were invented not long after photography itself came into being in the 1840s. The idea was to present the viewer of the stereographs with three-dimensional views of the world. In a time when photographs were just becoming common, stereoscopes added a dimension---well, two dimensions---to the experience. The stereoscope died off when motion pictures gave an even more realistic view of the world, but without the 3-D effect.
Basics
The stereoscope, essentially, is a hand-held device for viewing stereo or 3-D photos. It consisted of a usually wooden apparatus with two lenses, a handle, a stereograph holder and a piece of curved material, usually metal or leather, that contoured to the forehead to keep it in the correct position for viewing. You placed the three-dimensional image in the holder, then using the handle, held the device up to your face to look through the lenses. The effect is that you see the image in a apparent three-dimensional aspect with depth.
3-D Cameras
Stereoscopic cameras were needed to create the stereographs. These cameras, first created in the 1840s, have two lenses about as far apart as the human eyes. When you trip the shutter, both lenses expose images onto the film from slightly different angles. You place both of these images on a card next to each other. The human brain then merges the two images into one, creating the 3-D effect.
Popularity
By 1851, the Great Exhibition was under way in London. It was designed to highlight the Industrial Revolution innovations made by Great Britain and other countries. The stereoscope and stereographs played a part in capturing images of the exhibit, and allowed the rest of the world---those people who could not attend---to get a glimpse of it. The stereoscope was popularized because of this event.
Fascination
Oliver Wendell Holmes took up the idea of the stereoscope in the United States and helped to popularize it. He promoted the idea of creating libraries of images that could tell an entire 3-D story. In the 1850s, the stereoscope went from just being a hand-held device, to being an early multi-media center appliance in the home that provided a changing display of images like an early 3-D slide projector.
Enter the View-Master
Between the end of the 19th century and the early 20th century, stereographs were used in homes, but also in schools and other institutions for educational purposes. The 3-D effect was particularly good for teaching geography, for example. While the stereoscope by that name died off by the 1930s, the View-Master became a popular replacement by the 1950s. The View-Master was an update of the stereoscope. The images were place on a card in the shape of a wheel. The wheel was placed inside the View-Master and turned by means of a lever. The color 3-D images were used to show everything from Yosemite National Park to stories such as those about Lassie and Disney characters. These 3-D images were transparencies, and the reels were sold in collections, usually three-packs.
Tags: images were, hand-held device, were used