A stereograph consists of two side-by-side photographs which seem at first glance very similar. The difference between the two images is caused by the simultaneous exposure of one scene through the two lenses on one stereo camera.

The lenses, positioned on the camera, mimic the placement of eyes on the average human being. Stereography simulates the same three dimensional viewing as is experienced by viewing a scene through two eyes.

Normally, stereographs are viewed through a viewing device called a stereoscope. This is a device which forces the right eye to only see the right side and the left eye to only see the left side of the stereograph.

While viewing through a sterescope, the brain merges both sides of the stereograph, enabling the minds eye to see the scene in three dimensions. In the best stereo illusions one is able to see distinct differences between fore ground, middle, and background.

Viewing free of devices:

1) position the stereograph in front of yourself at a normal reading distance;

2) look at a distant spot beyond the stereograph by lifting your line of sight from 14 inches to 40 feet (looking at distant objects causes the eyes to diverge);

3) while focusing on your distant spot, quickly lower you line of sight back to the stereograph (when eyes are diverged the will see close objects as if the are in a right and left channel);

4) with a little practice, your eyes will stay diverged long enough to enable the right eye to only the right side and the left to only see the left side, the brain does the rest -- you will see the three dimensional image (with a lot of practice you are able to sustain divergent eye alignment). (Stereograph)