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TeleCine / Kinescope Laser holography |
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| TeleCine means scanning pre-recorded cine film, and converting it into electronic signals for display
on a TV set. Several companies including Kodak had systems based on this approach, but perhaps the most interesting
was called EVR (standing for Electronic Video Recording, even though it was a play-only system)
EVR was a collaboration between the chemical companies ICI and CIBA, the equipment manufacturer Motorola and the broadcasting giant CBS. The system was developed by Peter Goldmark - the head of R&D at CBS, and the man behind the invention of the LP record. | |
| The system used black-and-white film to hold recording, with the luminance signal as a normal image on
the film frame, and the chrominance signal as a series of encoded stripes next to this image. (The chroma track
could be used for a second recording if they were both black-and-white).
The pictures were read using the scannning beam of a TV tube, while the sound was stored as a
normal magnetic recording along one edge. The maximum playing time was 25 minutes.
EVR was unique in that complete frames were stored for each 50th of a second (or 60th, for USA & Japan); although no extra information was stored - each frame being constructed by doubling up a single field - this non-interlaced approach made the player much simpler and therefore cheaper. The philosophy was to put all the complexities in the recorder, at the factory, and to keep the actual player as simple as possible. |
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The innards of an EVR player -- note the valves (tubes) under the black covers,
and the take-up spool inside the machine.
This is not my machine (unfortunately!) - it's in the London Science Museum... |
| The completely baffling symbols on the EVR control buttons |
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EVR was first demonstrated in 1964, as a black and white system, though colour had been added by the time it actually went on sale, in 1969. It was not a great success. The inability to record, like many systems of the day, seems to have been one reason; in a popular book (Guerilla Television) Michael Shamberg branded EVR as "Extremely Vile Rip-off" and called it a "reactionary and irresponsible act of media sodomy"(!). CBS pulled out of the project in 1972, and the format struggled on in niche markets in Europe in Japan for a while before fading away.
The self-lacing EVR tape spool. The door would only open when the tape was rewound -- or, according to the manual (and rather worryingly) "if the film is in need of repair" |
SelectaVision |
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| The main rival to EVR was RCA's SelectaVision. Another playback-only system, it was based on the
brand new technology of holography, reading information from a transparent PVC tape using a laser beam.
The signal was not stored as an image, but as an interference pattern formed when two laser beams met at the tape.
This holographic system had the odd property that every spot on the film contained the entire image; even more curiously this meant that the tape speed was unimportant - the image reproduced by the laser beam remained fixed in space regardless of the movement of the tape, and was scanned electronically at the appropriate frame rate. This made the tape transport mechanism much simpler, so despite the state-of-the-art laser technology - SelectaVision would have been the first domestic use of lasers - the player was intended to sell for around $400, as opposed to EVR's hefty $1000 price tag [2005: $4,000 and $10,000]. Holographic SelectaVision |
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| Perhaps not surprisingly, although SelectaVision was also demonstrated in 1969, it never seems to have made it into the shops. | |
| In fact, RCA re-cycled the name SelectaVision for a prototype magnetic tape system, which also never went on sale, then for their short-lived capacitive disc format (known in the UK as CED, and covered in room 7), and finally as a label on their later VHS machines. It seems that they liked the name so much that they kept using it until a system actually made it to market!
Magnetic SelectaVision |
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