Hi, Simon,

I apologize for not responding sooner to your question.

Magentophonband Typ C was produced up until 1944 when the factory burned 
in an industrial accident. From then until the end of the war (and 
beyond) Typ L was the only tape manufactured in Germany (as far as I 
know). Typ L is Luvitherm (PVC) and is one of the few homogeneous tapes 
ever manufactured. Typ C is a much more conventional coated acetate tape.

When I transferred several dozen reels of Typ C (a total of 51 mostly 
Typ C and Typ L from the Mullin-Palmer collection and a few dozen more 
from the Eve Mullin Collier collection) all of the Typ C tapes played 
well, even though they were somewhat stiff. I can imagine that they have 
become even stiffer in the intervening years.

I transferred a half dozen Tonschreiber B reels (also Typ C, if I recall 
correctly) a few years later for Stanford (these were part of the Ampex 
Museum Collection which is now housed at Stanford). These had been 
stored in metal cans as opposed to the cardboard boxes of the other 
collections (I also did a few reels of mostly Typ L for the Pavek 
Museum). These reels stored in metal cans were suffering from vinegar 
syndrome.

The first caveat I have is that these tapes are 6.5 mm wide as opposed 
to 6.35 mm wide and if you are having difficulties playing them or they 
are bouncing around part of the issue may be binding in the guides. I 
ended up taking a file to the worn side of a set of fast guides in one 
of my Sony APR-5000 head assemblies in order to widen the guides to more 
easily accommodate the tape (I can loosen the guide and turn it back to 
a never-worn side for 6.35 mm wide tape).

The one tape that I had from the Eve Mullin Collier collection that was 
very stiff (much like a carpenter's tape measure with the cupping in it) 
was of concern. This was the early (circa 1935) tape and was only made 
for about two years if I recall correctly). I called Friedrich Engel in 
Germany and we talked about it a bit. He suggested a process of 
hydration. I placed the tape above some water in a closed plastic 
storage bin for about 24 hours.

When I removed the tape, it was like a silk ribbon--very pliable. The 
tape played fine (unfortunately, Mullin had used it as an experimental 
tape and there were only series of test tones on it. I ended up not 
digitizing it at all. Too bad, after all that work, but it proved the 
concept.

I tried rehydration once more with an acetate tape that had fallen 
behind a wood stove in Vermont and stayed there several winters. It was 
of no use because the edges of the tape were actually fused together in 
spots, so nothing would help. It appeared that the rehydration process 
weakened the tape, but the wood-stove treatment didn't do it any good 
previously.

If you are looking for more information about acetate film, the Image 
Preservation Institute (IPI) at Rochester Institute of Technology has 
some information on their website.
https://www.imagepermanenceinstitute.org/

Some of their papers are cited in my paper on tape degradation that was 
originally presented at the Audio Engineering Society's 121st convention 
in October 2006 in San Francisco was published in the ARSC Journal in 
the Fall of 2008. It is available here:
http://www.richardhess.com/tape/history/HESS_Tape_Degradation_ARSC_Journal_39-2.pdf

IPI is also a source of information on vinegar syndrome. As Tom 
mentioned, Kodak tape is quite susceptible.

Here are a few links related to Vinegar Syndrome from my site, including 
the old German tapes in cans.
http://richardhess.com/notes/2006/10/16/acetate-tape-buffered-by-cardboard-box/
http://richardhess.com/notes/2006/10/19/circa-1943-german-acetate-tape-anomaly-or-mine-canary/
http://richardhess.com/notes/2009/04/07/kodak-durol-triacetate-tape-with-bad-vinegar-syndrome/

Here is a list of many degrading tapes and the current thoughts of what 
to do with them.
http://richardhess.com/notes/formats/magnetic-media/magnetic-tapes/analog-audio/degrading-tapes/

I see while I was typing this Don Tait mentioned rehydration.

Cheers,

Richard

On 2011-12-08 6:48 PM, Simon Kunz wrote:
> Dear all,
>
> I would like to use camphor on a brittle acetate tape to smoothen it and make it playable. I have recently read of this procedure for film and I wondered if it would work in magnetic tapes as well.
> Does anyone have some experiences with this kind of treatment? Are there any published articles concerning this topic? (whether applied to film as to magnetic tape)
>
> The tape I would like to treat is a Magnethophon Typ C from 1943.
>
> Every hint is appreciated! If you prefer you may contact me off-list.
>
> Simon Kunz

-- 
Richard L. Hess                   email: [log in to unmask]
Aurora, Ontario, Canada           (905) 713 6733     1-877-TAPE-FIX
http://www.richardhess.com/tape/contact.htm
Quality tape transfers -- even from hard-to-play tapes.