posted 08-04-2004 07:42 AM                       

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I noticed the discussion about "Film Sound - history and technical details" on the film handler's forum at film-tech.com. A comment was brought up by Frank Angel about a process he believed "multichannel soundtrack based on the three emulsion colors, each color recording a single channel." Folks on the forum thought it might have been the Colortek system by John Mosley. I believe what he was referring to was an experimental variable-hue system developed by Petro Vlahos rather than by John Mosley (who did read the paper about the process at the "Film 75" conference in London.) The system did not use "each color recording a single channel" but rather recorded a push-pull style signal that varied the hue between red and cyan. Three side-by-side color tracks were used to give a three track sound system. The system is described in the September 1975 issue of American Cinematographer, which ironically also had an article describing the development of the Dolby Stereo optical print format. Of course, the variable hue format was incompatible with regular sound readers and required dual-inventory prints, which was part of what ensured its lack of success.

By the way, just to introduce myself -- I am the author of the "Wide Screen Movies Corrections" document that is on the "Tips" area on the film-tech.com web site. That document describes the many errors in the book "Wide Screen Movies" by Robert E. Carr and R.M. Hayes. I am chasing down some additional details and hope to release an updated version in the near future. At the present time, it is about 50% larger than the older version (which says something about how many errors there were in that book.) Anyway, I have been a "lurker" at the film-tech.com site for quite a while now, and since nobody seemed to clear up the "color modulated" subject, and since you have a good historical background on the subject, I thought I would pass on this info to you.

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Dan Sherlock
Systems Engineer
Film Format Historian
Member, SMPTE & BKSTS

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posted 10-26-2004 03:13 PM                    

quote: Ken Lackner

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So Woody Allen films are technically SR, right?

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quote: Martin Brooks

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Popeye was released in Vistasonic

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The Vistasonics I remember was used on another picture [besides] Popeye and there were a number of experiements around the SF bay area.

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quote: Martin Brooks

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My notes do say that it played at five theaters in that format in NY, Los Angeles and Chicago.

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I am unaware if this system was ever used commercially.

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