I'm virtually sure that Mitchell Heller's observations about humidity as
a treatment for dried-out, warped acetate tape were never published (your
message is forwarded, I hope).
Thanks to you and Steve Smolian and all others about this question.
From: Patent Tactics, George Brock-Nannestad
humidity works, according to Nadja Wallaszkovits (Phonogrammarchiv, Centre
for Linguistics and Audiovisual Documentation, Austrian Academy of Sciences,
Vienna). It is part of the re-plastification process she reported on without
giving details in Berlin in June (see my report of 14 June 2011 on ARSCLIST).
A patent had been applied for, publication was to be "soon", but to my
knowledge this has not yet happened. Perhaps your information from Mitchell
Heller was published in its day, and this could prevent patenting today. In
such a situation, the applicant frequently withdraws the patent application
without letting it publish, to keep the information to himself, as there are
no rights to be derived from it.
P.S. I have just read the posts by Richard Hess and Steven Smolian, and I
Don Tait wrote:
> I agree with Scott Phillips. I'd like to read everyone's comments about
> this on the ARSC site if everyone is willing. Because I have some acetate
> tapes from circa 1957 that are dried, curled, and that I want to preserve.
> I'll tell something that was told to me about a possible rescue method
> by Mitchell Heller, who's been an engineer involved in recording since the
> early 1950s: humidity. Mitchell said the basic problem is that acetate tape
> dries out, and curls as a result. He recommended putting a piece of wet
> cloth or paper towel in at least one corner of a tape enclosure, the more
> corners the better, trying to cover all openings of the enclosure with
> like plastic wrap to trap the moisture inside, and letting it sit for a
> while. He said that would rehydrate the tape and cause it to flatten enough
> to be played successfully.
> Despite my problems with a few acetate tapes I've never had the energy
> to try it, so I don't know whether it works. Others probably will. In any
> case, that's my contribution. I hope to read others' thoughts about the
> Don Tait