Stereoscopic photography became popular soon after the introduction of photographic processes by Daguerre and by
Talbot in 1839. Stereoscopic images were most often viewed as side-by-side left- and right-eye image pairs, using
viewers with prisms or mirrors. Superimposition of encoded image pairs was envisioned as early as the 1890s, and
encoding by polarization first became practical in the 1930s with the introduction of polarizers in large sheet form. The
use of polarizing filters enabled projection of stereoscopic image pairs and viewing of the projected image through
complementary polarizing glasses. Further advances included the formation of images that were themselves polarizers,
forming superimposed image pairs on a common carrier, the utilization of polarizing image dyes, the introduction of
micropolarizers, and the utilization of liquid crystal polarizers.