A 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. 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.
Stereo 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.
Manufacturing Stereoview Cards