I think I found most of my answer, in an obvious place ;) ...
see page 432 onward.
Summary: SMPE meets to discuss magnetic recording right after WWII; in 1947, DuPont develops
mag-coated film and RCA develops a retrofit kit for one of their 35mm optical recorders; by 1951,
RCA had developed 1, 2 and 3-track magnetic-film recorders and Columbia Pictures was using that
equipment (and then printing to optical for editing!). Also in 1951, Westrex reported developing
magnetic recorders for various track layouts and various film widths. The SMPE Progress Report of
1952 reports that by the end of 1951, "approximately 75% of the original production recording, music
scoring and dubbing in Hollywood was being done on magnetic-recording equipment."
Kellogg, always worth checking for the history of anything sound-for-picture up to the mid-50's! The
full article is linked from here:
-- Tom Fine
----- Original Message -----
From: "Tom Fine" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, February 09, 2012 8:15 AM
Subject: [ARSCLIST] Early 35mm magnetic film history in Hollywood
> Hello ARSC brain trust:
> Does someone know exactly when folks in Hollywood started using magnetic-coated film in their
> sound recordings? I found this article from a Dolby executive:
> which seems to put the date around 1952, with the development of Cinerama, which apparently used
> stripe-coated magnetic tracks. I think Westrex developed its stripe-coat and full-coat recorders
> around that same time, and that magnetic recording of master tracks started to become common as
> the various widescreen formats developed in the early 1950's. Is this historically correct?
> Thanks in advance for your input.
> -- Tom Fine