Slide cube projector
The Slide Cube Projector is a slide projector and system, manufactured and marketed by Bell & Howell through the 1980s. The system derived its name from it's plastic slide storage cubes, which were about 5.5 cm in each dimension (a bit larger than a slide), and held 36–44 slides, depending on the mount thickness. The system consisted of Slide Cubes and a special projector to receive the cubes. An optional lid, could hold approximately 16 cubes.
Unlike trays used in straight-tray or carousel slide projectors, the slides in a Slide Cube are not separated from each other; they are stacked one on top of the other. The slide advance mechanism first allows a slide to drop from the loaded cube into a slide-size hole in a circular, rotating plate with four positions. The plate is thinner than a slide and allows only a single slide to drop and move forward to a preview position, projection position, and return position (from which it can be returned to allow for a single slide's worth of backup, and then finally to a reload position, where it drops into a stack that is then manually elevated up into an empty cube.
Bell and Howell Slide Cube Projectors were less expensive than trays and allowed for higher storage density, where a book or drawer of 16 forty-slide cubes (640 slides) occupied the space of a single round tray holding at most 140 slides. The stack storage and preview feature also make for easier editing of slide shows; slides can be added to or removed from the show without having to shift all of the remaining slides up or down in their slots one at a time. Some tray-based projectors (e.g. some Kodak round-tray and Hähnel straight-tray slide projectors) can use stack loaders to view a stack of slides, but they don't lend themselves to this type of operation and there is no associated storage system.
The slide cube had drawbacks, including the inability to reverse to more than one slide, the fragility of the cubes, and the advancing plate's tendency to jam — interrupting slide shows and making the projectors unsuitable for those with less mechanical aptitude.
Though Slide Cube Projectors are no longer manufactured, cubes, bulbs and a few replacement parts as well as used projectors and cubes remain available on the second hand market.
See also