Unlike other motion picture film stock of the time, Polavision film reproduces color by the additive method, similar to Kodachrome of the time. In essence, the film consists of a black-and-white emulsion on a film base covered with microscopically narrow red, green and blue filter stripes. It was instant in the sense that it could be very quickly and easily developed in the Polavision processing unit after it was removed from the Polavision camera, ready for viewing in only a few minutes.
The Polavision cartridge called Photo tape cassette is a small rectangular box containing the film reels and a prism letting in light for projection through a film gate. The film format is similar to the super 8mm cine film format, but without this Polavision tabletop viewer the only way a Polavision film can be shown is by destroying the cartridge and projecting the removed film with an ordinary super 8 mm projector or transferring it to video with a telecine system.
Sadly the Polavision system was a major commercial failure, and was discontinued in 1979. However, the underlying technology was improved and used as the basis for the commercially successful Polachrome instant color transparency system introduced in 1983.
This is a rare, early model Polaroid Polavision tabletop processor & viewer for Polavision instant cine film cartridges, believed to be in working order but currently not powering up