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Dead medium: RCA SelectaVision Holographic Videofilm
From: (David Morton)
Source(s): "Color TV tape player employs lasers and holography"
IEEE Spectrum 6 (Dec 1969): page 28

(((David Morton remarks: The following article describes one of the several different technologies that RCA considered or actually marketed under the name "SelectaVision." Other technologies included the SelectaVision capacitive videodisk and the SelectaVision VHS videotape system. The film-based system described below, which never went into production, coincided with but was significantly different than the film-based "Electronic Video Recording" technology developed at the same time by CBS, which was also a commercial failure.)))

"A laboratory model of a low-cost television color tape player built around lasers and holography and destined for home use in the early 1970s was exhibited recently by RCA. In commercial form, the SelectaVision player, which will be designed to attach to any standard color television set, will play full-color programs recorded on tapes made of the same clear, inexpensive plastic materials used in super-markets to wrap meats.

"These tapes will be scratch proof, rustproof, and bb virtually indestructible under normal use. The conversion process is described as follows: a color program originating from a color television camera or color videotape player is recorded on conventional film by means of an electron beam recorder. This film, known as the color encoded master, is then developed and convened by a laser to a series of holograms recorded on a plastic tape recorded with photoresist, a material that hardens to varying degrees depending upon the intensity of the light striking it.

"Next, the tape is developed in a chemical solution that eats away the portions of the photoresist not hardened by the laser beam. The result is a relief map of photoresist whose hills and valleys, and the spacing between, represent the original color television program in coded form. This is called the hologram master.

"The hologram master is plated with a thick coating of nickel and stripped away, leaving a nickel tape with the holograms impressed on it like a series of engravings. This is the nickel master.

"Finally, by feeding the nickel master through a set of pressure rollers along with a transparent vinyl tape of similar dimensions, the holographic engravings on the master are impressed on the smooth surface of the vinyl as holographic reliefs. The result is a SelectaVision program tape ready for home use.

"Playback of such a tape requires only that the beam from a very-low-power laser pass through it into a simple, low-cost television camera that sees the images reconstructed by the laser directly, and their colors as coded variations in those images. The playback mechanism, the laser, and the television camera are all housed in the SelectaVision player, which is attached to the antenna terminals of a standard color television set for actual viewing."

David Morton ( IEEE Center for the History of Electrical Engineering Rutgers University