Series contains stereoscopic viewers, photographic images, and emphera. This includes a wide range of stereoscopes and three-dimensional viewers. Stereoscopes are devices used to view two mounted identical images as a single three-dimensional photograph commonly referred to as stereographs or stereoviews.
The first lens-based, portable stereoscopes were invented by Sir David Brewster in 1849 and presented at Crystal Palace during the London Great Exhibition between 1850 to 1851. Until a decade later when Oliver Wendell Holmes' adaptation of the Brewster stereoscope became the model for all later editions of stereoviewers during the 19th century. Holmes left his invention unpatented. This allowed other manufactures such as H.C. White, Underwood & Underwood and Keystone Viewing Company to mimic his design and increase production of stereoscopes and stereoviews. Ultimately, Holmes' decision would increase production and purchase of his invention.
Stereoscopes and stereo ephemera were meant for educational and entertainment purposes. Designs ranged from various materials like wood and aluminium, stereoscopes also had a large array of shapes and sizes from hand held to table top.
Following the 20th century, three-dimensional viewers became extremely popular. Some major manufactures such as GAF, Sawyer's View-Master and Tru-View produced iconic viewers made from metal, bakelite and other plastics. Originally, viewers and viewer emphera were developed for educational purposes but eventually became marketed as children's entertainment. Unlike stereoscopic viewers that could only look at single card stereoviews, three-dimensional viewers typically rotated black and white or colour transparency reels or multiview cards. Many original companies such as Sawyer's and GAF merged together but maintained the "View-Master" name. In 1989, the view-master brand was sold to Tycho until 1997 when Mattel and Tyco joined together. Now, view-masters are produced under the Fisher-Price title. View-masters were made from various materials and sizes. Some editions included built-in back lighting and sound recordings.