Slide viewer

Images in color on small pieces of Kodachrome film came mounted in rectangular openings near the edge of a cardboard disk, which, despite being quite flat, was officially known as a View-Master "reel".

Eventually, the viewers were available in several models, including some that were illuminated by flashlight bulbs powered by a line current transformer or batteries, as well as "talking" View-Masters.

Another category is scenic views associated with a tourist destination, typically sold at gift shops located at the attraction.

Using Kodachrome or other 35 mm slide film, this equipment made startlingly lifelike amateur stereoscopic color photography possible at a reasonable cost.

To magnify the images so that they will occupy a much larger visual angle and still be sharp and undistorted, suitable high-quality multi-element short focal length lenses must be used.