John Chester reminded me of an October 2005 post that I made to ARSCLIST that I had not mentioned in depth here. To keep as much information as possible in this one place, I thought I’d re-post it here with minor edits for clarity 13 years later:
Friedrich Engel, the retired BASF historian, gave me a present in a phone conversation (yes, to Germany, his English was far better than my German). You can re-hydrate acetate tapes.
The procedure I used, based on discussions with Engel, was to place the tape in a 100% humidity atmosphere for about 24 hours.
The subject tape was a 1935 Carbonyl Iron tape from the Jack Mullin collection. Too bad, there were only a few tones on it, but it played.
When I first got it, it behaved much like a carpenter’s steel tape measure and you could hold a foot or more of it extended. After the treatment, it felt like a satin ribbon.
I placed the tape in an open container inside a sealed container. The sealed container had about an inch of water in the bottom, the open container was above that. The tape was up on spacers in the open container. This was room temperature.
I tried this again with a tape that spent several years behind a wood stove and it did soften it a bit, but the tape was too blocked (adhered layer to layer by edge melting) and too fragile to play either before or after this treatment, although the fragile pieces were much softer even after this treatment.
I would suggest trying this with one reel that is not as important to get the “feel” of the process.
If it works, thank Herr Engel, if it doesn’t please let us know about your experiences.
I would think this is safer than trying to force the tape into contact by either tension or pressure pad, though, when the tape is already supple, pressure pads can work wonders as well.
I make no warranties as to the long-term effects of this treatment.