Hi Tom,
I cannot identify the tape base. It doesn＊t pass light through the side of
the reel - the reels are absolutely opaque. But they also appear to be
0.5 mil - which doesn＊t always pass light when viewed through the side of
the tape pack.
Detailed tape info:
TDK-E (TDK Electronics)
Synchrotape
Type 12A-PL-8
Only one of the reels was stored in a sealed plastic bag. It was
mechanically the strongest and most flexible in the collection (the entire
collection is on TDK Synchrotape). It was the only tape that could be
leadered and played. The strongest sign that the tapes may be acetate is
that only this one tape had a distinct vinegar smell when the plastic bag
was opened.
We regularly humidify tapes on acetate base. That＊s my next step. We＊ve
had good success with this in general, but these tapes are the worst we＊ve
seen yet - the outer wraps are fused and the shrinkage is fairly extreme
as well.
I＊m hoping these tapes are indeed double- or triple-play acetate, and that
the humidification succeeds.
Tom, you mention cellulose acetate film. Do you know if anyone has used
camphor (plasticizer used with cellulose nitrate film) to revive acetate
audio tape?
~ Eric
On 1/29/16, 4:28 PM, "Association for Recorded Sound Discussion List on
behalf of Tom Fine" <[log in to unmask] on behalf of
[log in to unmask]> wrote:
>Hi Eric:
>
>Is this acetate-backed tape for sure? The description makes it sound that
>way. If it is, I recommend
>you try humidifying it for a while, let it get thoroughly humidified, and
>then play it in a
>relatively warm environment. All of that might make it less brittle, and
>also it might curl less as
>it goes through the guides. Just a theory, but in my experience, acetate
>will behave better if it's
>not super dry. I don't know of a great way to humidify it. Maybe leave it
>in a commercial greenhouse
>for a few days? Not the paper box, of course.Watch out for mold, too,
>there may be spores all over a
>greenhouse. Certain molds grow on and eat acetate, I know this for a
>fact. So maybe put it in a
>sealed oven at relatively low temp (maybe 100-120 degrees F, maybe less)
>with a water source that
>can evaporate and infuse the acetate over a time period? I'd experiment
>with a junker reel first! I
>can send you some edge-curled but not vinegar Scotch 111 to play with.
>Can't say if it would behave
>exactly the same way as the Japanese tape.
>
>By the way, there were several articles over the years in the SMPTE
>Journal about the long-term
>problems and breakdowns of cellulose (acetate) base for films. I assume
>the same problems and
>mechanisms described apply to thinner-base magnetic tapes. A lot of SMPTE
>Journals are online at
>archive.org, but maybe not the later era of which I speak (articles
>appeared in the 1980s).
>
>-- Tom Fine
>
>----- Original Message -----
>From: "Eric Jacobs" <[log in to unmask]>
>To: <[log in to unmask]>
>Sent: Friday, January 29, 2016 7:13 PM
>Subject: [ARSCLIST] playback of disintegrating open reel tape
>
>
>We have a 1/4-inch open reel tape (TDK Synchrotape ca 1966 Japanese stock)
>that is quite literally disintegrating and cannot hold any tension. The
>very slightest amount of tension causes the tape to snap. The tape cannot
>even hold a leader without snapping. We易ve turned the tape tension way
>down
>on our Studer A820, but it can易t be pulled through the transport without
>snapping.
>
>The tape is heavily curled along the edges (only the center 25% is flat)
>and
>is anything but straight from exposure to presumably high temperatures
>over
>the past 50 years. The outer wraps have bonded to each other. We can
>deal
>with the edge curl and the age-induced country-laning by using a custom
>mechanism that gently increases the tape wrap around the PB head (forces
>the
>tape flat) and additional edge guides fore and aft of the PB head that
>keeps
>the tape centered on the head. We can even separate the outer wraps,
>albeit
>in 1-inch segments that would need to be spliced together 〝 this seems
>like
>a bad idea, but I don易t see any other choice if we want to get past the
>outer wraps.
>
>But it易s the fragility of the tape (lack of tensile strength) that is the
>central issue. If it were possible to 昆back昌 the tape, it might keep it
>from snapping. But how do you efficiently and reliably 昆back昌 1200 feet
>of
>tape that snaps with the slightest bit of handling? And what do you back
>the tape with? Splicing tape? It might be easier to apply backing to the
>centerline of the tape rather than the full width because of tape
>shrinkage
>and edge distortion, but then the resulting tape pack would probably be
>quite poor, especially if the backing doesn易t stack precisely on top of
>the
>previous wrap. Also, a narrow backing (like cassette splicing tape) may
>or
>may not affect the ability to force the tape flat at the PB head 〝
>essential
>for a quality transfer.
>
>Looking for ideas and suggestions.
>
>~ Eric
>
> Eric Jacobs, Principal
> The Audio Archive
> 1325 Howard Ave, #906, Burlingame, CA 94010
> Tel: 408-221-2128 | [log in to unmask]
> www.theaudioarchive.com <http://www.theaudioarchive.com/>
>
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