stereogram or stereoview is a flat two-dimensional image viewed in such
a fashion as to produce a three-dimensional effect..Stereographic photography
was invented almost immediately after photography itself. During the Victorian
era photographers were sent out to photograph the world in 3D, and the
photographs were reproduced over and over to meet the demand -- manufacturing
and assembling the views was big business. Looking at stereographs was
as common in Victorian times as watching TV is today. People would relax
in their parlor and be transported around the country and around the world
with a box full of stereos and a hand-held or tabletop viewer.
pictures are taken by means of a camera with two lenses. This provides
two separate pictures 2.5 inches apart, about the distance between the
eyes. Although the pictures appear the same, they are not. When looked
at in a viewer, which has prismatic lenses, your eyes will blend the two
views into one and the brain perceives it in three dimensions the same
as normal vision. It's estimated that over 7 million different images were
commercially produced, and these had runs anywhere from a handful to thousands!
The demise of the stereoscope began with the advent of other forms of entertainment
media and by the 1940s, about the only type of stereoviewing available
was the View Master.