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AGFA tape baking problem: please help

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Anonymous
October 12, 2004 11:53:52 PM

Archived from groups: rec.audio.pro (More info?)

I am currently working on an archiving project for an NPR radio
program, transfering 1/4 inch tape masters to computer to clean them
up. Out of necessity, we've been baking most of our tapes to get them
to play properly. Recently though, the current season (from 1989) I'm
working on used mostly AGFA 469 tape which has been by far the worst
for oxide shedding.

My problem is this: after the AGFA tape has been baked (at 140F for 6
hours in a covection oven) I've noticed the oxide sticks to the splice
tape, creating "holes" in the oxide above the splice in the tape wind.
At first, I thought this had happened before the baking, but now I
realize it is a result of the baking.

What can I do to prevent this? Obviously the tape has to be baked. Our
current oven does not go below 140 (but the temperature does remain
constant). I'm at a loss.

I'd appreciate your help.

Evan Hill
Anonymous
October 13, 2004 12:48:17 PM

Archived from groups: rec.audio.pro (More info?)

Evan Hill <wilsonrock@charter.net> wrote:
>I am currently working on an archiving project for an NPR radio
>program, transfering 1/4 inch tape masters to computer to clean them
>up. Out of necessity, we've been baking most of our tapes to get them
>to play properly. Recently though, the current season (from 1989) I'm
>working on used mostly AGFA 469 tape which has been by far the worst
>for oxide shedding.
>
>My problem is this: after the AGFA tape has been baked (at 140F for 6
>hours in a covection oven) I've noticed the oxide sticks to the splice
>tape, creating "holes" in the oxide above the splice in the tape wind.
>At first, I thought this had happened before the baking, but now I
>realize it is a result of the baking.
>
>What can I do to prevent this? Obviously the tape has to be baked. Our
>current oven does not go below 140 (but the temperature does remain
>constant). I'm at a loss.

Is the tape squealing, or is it just shedding? That tape was notorious
for shedding when it was new. Fast-forwarding and rewinding over a Pelon
cloth will clean the residue off and reduce the shedding if it's a shedding
problem. Baking will not help a shedding problem.

IF you have a sticky-shed problem, this is different than normal shedding
and you can tell because the stuff left on the heads is gummy rather than
powdery, and it's sometimes even white rather than brown. If you have
sticky shed issues, you will probably need to redo all of the splices
with blue tape, if they were done with white tape. I don't know how the
tabs fare through the baking process.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
October 13, 2004 1:58:22 PM

Archived from groups: rec.audio.pro (More info?)

In article <ff839d57.0410121853.73b51c3f@posting.google.com> wilsonrock@charter.net writes:

> working on used mostly AGFA 469 tape which has been by far the worst
> for oxide shedding.
>
> My problem is this: after the AGFA tape has been baked (at 140F for 6
> hours in a covection oven) I've noticed the oxide sticks to the splice
> tape, creating "holes" in the oxide above the splice in the tape wind.
> At first, I thought this had happened before the baking, but now I
> realize it is a result of the baking.
>
> What can I do to prevent this? Obviously the tape has to be baked.

No, it doesn't. and you shouldn't bake Agfa tape. It had an oxide
shedding problem, but it's not the same "sticky shed" problem that's
cured by baking.

Stand back, let it shed, and clean the tape deck's heads and guides
as often as necessary. Lots of this tape shedded large piles of oxide
even when it was new. There's nothing you can do about it to make it
better, but you've discovered one way to make it worse. Don't bake
the other reels.

--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Related resources
Anonymous
October 13, 2004 6:29:32 PM

Archived from groups: rec.audio.pro (More info?)

mrivers@d-and-d.com (Mike Rivers) wrote in message news:<znr1097673399k@trad>...
>
> > What can I do to prevent this? Obviously the tape has to be baked.
>
> No, it doesn't. and you shouldn't bake Agfa tape. It had an oxide
> shedding problem, but it's not the same "sticky shed" problem that's
> cured by baking.
>
> Stand back, let it shed, and clean the tape deck's heads and guides
> as often as necessary. Lots of this tape shedded large piles of oxide
> even when it was new. There's nothing you can do about it to make it
> better, but you've discovered one way to make it worse. Don't bake
> the other reels.

Okay, thank you. I understand this better now.

But I have to retract on my original statements. With further
research, I noticed some of the AGFA tapes create the previously
mentioned "holes" without baking. I thought maybe, instead of baking
process, it was the process of fast rewinding them onto metal flanges
from plasic flanges that created the mass oxide shed onto the backs of
splices (blue tape, in case you were wondering). But even with slow,
finger-on-the-flange hand winding (much slower than playback speed),
the splices still stick and end up partly covered in oxide, creating
those audible "holes."

What do I do now? The prospect of very, very slow winding doesn't
seem like a viable option, as this is already a long project (5 more
years worth of weekly shows), and such slow winding would double or
triple the work time. Plus this project is grant funded, and as we all
know, grant money does not last forever.
Anonymous
October 14, 2004 12:53:13 AM

Archived from groups: rec.audio.pro (More info?)

In article <ff839d57.0410131329.5d6c2ba0@posting.google.com> wilsonrock@charter.net writes:

> But even with slow,
> finger-on-the-flange hand winding (much slower than playback speed),
> the splices still stick and end up partly covered in oxide, creating
> those audible "holes."
>
> What do I do now? The prospect of very, very slow winding doesn't
> seem like a viable option, as this is already a long project

This is why recorded sound preservationists (that's you!) get paid the
big bucks. You find problems, almost always physical problems, and you
work around them. I'd suggest that you use a slow machine wind while
watching the tape on the reel very carefully, then when you see a
splice is about to come along, stop, and wind it manually very slowly.
You may be able to save some of the spots where the splicing tape
adhesive is sticking.

You may just have to live with the dropouts, but the fewer the better.

--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Anonymous
October 14, 2004 9:46:57 AM

Archived from groups: rec.audio.pro (More info?)

mrivers@d-and-d.com (Mike Rivers) wrote in message news:<znr1097708011k@trad>...

>
> This is why recorded sound preservationists (that's you!) get paid the
> big bucks. You find problems, almost always physical problems, and you
> work around them.

Ha! Big bucks! I wish. I don't think the grant people who pay me see
it quite the same way as you do. I had co-workers at Sears putting up
sale signs making more than I do now.

But yes, I do work around the problems; that's what I've been doing
this whole time. It's tedious and frustrating sometimes. And sometimes
there is simply nothing I can do to fix the situation. I was just
hoping I could learn ways keep the tape transfer more authentic to
what is on the tape masters.

Thanks for your help.

Evan Hill
Anonymous
October 15, 2004 10:53:35 AM

Archived from groups: rec.audio.pro (More info?)

mrivers@d-and-d.com (Mike Rivers) wrote in message news:<znr1097673399k@trad>...
>
> No, it doesn't. and you shouldn't bake Agfa tape. It had an oxide
> shedding problem, but it's not the same "sticky shed" problem that's
> cured by baking.
>
> Stand back, let it shed, and clean the tape deck's heads and guides
> as often as necessary. Lots of this tape shedded large piles of oxide
> even when it was new. There's nothing you can do about it to make it
> better, but you've discovered one way to make it worse. Don't bake
> the other reels.

Okay, having played these AGFA tapes both with and without baking
them, the tapes play better after baking them. Without baking the
tape, I lose a lot of high frequencies and have to clean the heads
after about 3 minutes of playback. I can actually hear the tape hiss
slowly fading away. This never happened when the tapes were baked.

So you say the tapes "shouldn't" be baked because it is just an oxide
shed problem. Is there a reason they shouldn't be baked? I've
determined the dropouts were a winding and not a baking problem.
Sticky shed or no, it seems that the baking process better adheres the
oxide to the adhesive.

Another more fundamental question: If the tape is losing enough oxide
to affect accurate playback in 3 minutes, how does this amount of
shedding affect the quality of the tapes for later playings? What is
being lost, in other words? Obviously, this question is less crutial
because it's my job to preserve (and enhance in some ways) the
recordings in the state they are in right now by transfering them to
another medium. I'm just curious for my own edification.
Anonymous
October 15, 2004 2:09:50 PM

Archived from groups: rec.audio.pro (More info?)

Evan Hill <wilsonrock@charter.net> wrote:
>
>Okay, having played these AGFA tapes both with and without baking
>them, the tapes play better after baking them. Without baking the
>tape, I lose a lot of high frequencies and have to clean the heads
>after about 3 minutes of playback. I can actually hear the tape hiss
>slowly fading away. This never happened when the tapes were baked.

469 was almost that bad when it was new, until BASF took over and fixed
the problems. I don't remember when that was, but the stuff I was getting
in 1987-1988 was a major shedding pain, and the stuff I got in 1994 or so
wasn't.

>So you say the tapes "shouldn't" be baked because it is just an oxide
>shed problem. Is there a reason they shouldn't be baked? I've
>determined the dropouts were a winding and not a baking problem.
>Sticky shed or no, it seems that the baking process better adheres the
>oxide to the adhesive.

Fast forward and rewind on Pelon. It should clean all the stray oxide off
the tape and everything should be more or less fine on playback. If it
isn't, baking might be a good idea. But if the stuff you are cleaning off
the heads is flaky and not gummy, baking is not a good idea.

A yard of Pelon or some other interlining material should be three or four
bucks at your local fabric store. It will do wonders for shedding tapes.

>Another more fundamental question: If the tape is losing enough oxide
>to affect accurate playback in 3 minutes, how does this amount of
>shedding affect the quality of the tapes for later playings? What is
>being lost, in other words? Obviously, this question is less crutial
>because it's my job to preserve (and enhance in some ways) the
>recordings in the state they are in right now by transfering them to
>another medium. I'm just curious for my own edification.

Probably not very much, but that was a big bone of contention when these
tapes were new and it still hasn't really been settled. These tapes always
had major shedding problems.

I suspect that no matter what happens you are going to need to redo all
the splices. I strongly recommend the tabs.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
October 15, 2004 4:16:05 PM

Archived from groups: rec.audio.pro (More info?)

<< It's tedious and frustrating sometimes. >>




Sounds like a job for Intern Boy!



Joe Egan
EMP
Colchester, VT
www.eganmedia.com
Anonymous
October 17, 2004 5:08:31 PM

Archived from groups: rec.audio.pro (More info?)

eganmedia@aol.com (EganMedia) wrote in message news:<20041015081605.27265.00002578@mb-m03.aol.com>...

> Sounds like a job for Intern Boy!

Here I am to save the day.
Anonymous
October 18, 2004 11:45:53 AM

Archived from groups: rec.audio.pro (More info?)

In article <ff839d57.0410150553.2cac7d50@posting.google.com> wilsonrock@charter.net writes:

> So you say the tapes "shouldn't" be baked because it is just an oxide
> shed problem. Is there a reason they shouldn't be baked?

There's different chemistry involved with Agfa tape. If baking
improves the playing, it's doing it for a different reason than with
Scotch or Ampex tape.

You shouldn't be playing badly deteriorated tape more than once
anyway, so if you've found something that makes it play better once,
go ahead and do it. But don't plan on doing it again. Not to say that
you won't be able to, but you may be making matters worse for the long
term. It's a decision you have to make.

> Another more fundamental question: If the tape is losing enough oxide
> to affect accurate playback in 3 minutes, how does this amount of
> shedding affect the quality of the tapes for later playings?

The greatest reason for loss is the tape not making good contact with
the head due to the oxide buildup. That's something that will be fixed
by cleaning, and some of the highs will come back. But there IS a loss
of material so it will never be as good as new. There is no
quantitative measure for this. It's just that every time you play the
tape, you reduce its fidelity a little.

There are no shortcuts to this process. It's tedious, and unless
you're being well paid for your time (which you apparently aren't)
it's a relatively thankless job. Either you decide to commit to doing
the best job you can or you play the tape, record what you got, and
move on. It's up to you.


--
I'm really Mike Rivers - (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Anonymous
October 20, 2004 4:39:19 AM

Archived from groups: rec.audio.pro (More info?)

mrivers@d-and-d.com (Mike Rivers) wrote in message news:<znr1098097858k@trad>...
> In article <ff839d57.0410150553.2cac7d50@posting.google.com> wilsonrock@charter.net writes:
>
> > So you say the tapes "shouldn't" be baked because it is just an oxide
> > shed problem. Is there a reason they shouldn't be baked?
>
> There's different chemistry involved with Agfa tape. If baking
> improves the playing, it's doing it for a different reason than with
> Scotch or Ampex tape.
>

I used AGFA 468 & 469 a/4", 1/2" and 2" for many years, and the BASF
911 that followed the change of ownership. There were 2 different
conditions that occurred with the AGFA formulations

1. Oxide shed - that made clients VERY nervous, and it was sometimes
spectacular to observe. The oxide shed happened straight out of the
box with new tape, and continued throughout the life of the project.
Oddly, it never affected any of the projects I worked on. I never lost
high end, low end or overall signal level. It smelled funny, I
vacuumed more often, but it was fine. It was great sounding tape, and
it was quieter with much less print-through than any other tape, IMHO.

2. Goo - after storing for several years, the tapes started oozing
goo. The goo would build up on the oxide side of the guides during
fast wind, and would eventually grind my MCI 2" machine and my 1/2"
machine to a halt. It wouldn't play, it wouldn't wind... it would just
sit there and groan. I could chip the goo off the guides & heads, then
wipe it down with alcohol or head cleaner, it would play for a couple
of minutes, then grind to a halt.

Goo was described to me (by the agfa rep) as a problem that was
similar to the 3m and Ampex problems fixed by baking; the binder that
they used to adhere the oxide to the mylar deteriorated and turned to
.... well, goo.

AGFA/BASF admitted the problem and had a program in the 90's where
they would pay for your tapes to be baked and transferred to the
format of your choice. I called the company in Florida that had the
BASF contract to find out how they handled the tapes, because I was
familiar with baking the tapes in a convection oven, and was willing
to do the transfers myself, rather than risk shipping them off and
back.

This is where it gets a little weird. The guy said that they
microwaved the tapes. They removed the flanges and screws, and put
them in a microwave at low power; 1/4" to 2" tapes; it didn't matter.

I tried it. It worked great. The tapes came out smelling like they did
when I first bought them, and the tape was very "relaxed," that is,
even though they may have gone in the microwave with a nice, even,
factory wind, they came out very loose. I had to be very careful with
the 1/4" reels that they didn't unravel before I put the flanges back
on.

Now, that was the mid/late 90's when I did that. Don't ask me how long
I baked them, or what brand microwave I used etc. I just recall
putting the microwave on about 1/3 power, and doing it on a spinning
platter until they felt warm and almost hot. Very unscientific, but
very effective.

I still have those old tapes, and the 2" was transferred to ADAT. They
sounded fine after being "microwaved." I seem to recall being told
that the transfer had to happen within a couple weeks, and then the
tapes would lose their flux or something. I don't know; I never put
them on the machine after I did the transfer, and I transferred within
a day.

I hope this is addressing the original question in the thread.

Bob Singleton
Anonymous
October 20, 2004 2:49:17 PM

Archived from groups: rec.audio.pro (More info?)

In article <955c39a4.0410192339.14372c06@posting.google.com> BobS@SingletonProductions.com writes:

> 2. Goo - after storing for several years, the tapes started oozing
> goo. The goo would build up on the oxide side of the guides during
> fast wind, and would eventually grind my MCI 2" machine and my 1/2"
> machine to a halt.

I had one of those projects that dragged on for years that I did on
Agfa 468. It shed like crazy when new as you described, and then near
the end of the project got sticky. I actually built a duct using
cardboard and duct tape (real duct tape) to direct the warm air from
the exhaust fans on my MM1100 across the top plate and blow right on
to the tape just ahead of the first guide. It worked fine. Not exactly
"baking in place" but more like drying the goo before it hit the
stationary parts.

> AGFA/BASF admitted the problem and had a program in the 90's where
> they would pay for your tapes to be baked and transferred to the
> format of your choice.

> This is where it gets a little weird. The guy said that they
> microwaved the tapes. They removed the flanges and screws, and put
> them in a microwave at low power; 1/4" to 2" tapes; it didn't matter.

Yes, I remember reading this. Apparently their problem was more like
what we imagine the "sticky shed" to be, and that's a tendency to
absorb moisture. The real 3M/Ampex sticky shed was a chemical
breakdown of the binder. Heating the tape allows the components to
recombine and it's good as new.


--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Anonymous
October 20, 2004 3:18:46 PM

Archived from groups: rec.audio.pro (More info?)

Bob Singleton <BobS@SingletonProductions.com> wrote:
>
>I tried it. It worked great. The tapes came out smelling like they did
>when I first bought them, and the tape was very "relaxed," that is,
>even though they may have gone in the microwave with a nice, even,
>factory wind, they came out very loose. I had to be very careful with
>the 1/4" reels that they didn't unravel before I put the flanges back
>on.
>
>Now, that was the mid/late 90's when I did that. Don't ask me how long
>I baked them, or what brand microwave I used etc. I just recall
>putting the microwave on about 1/3 power, and doing it on a spinning
>platter until they felt warm and almost hot. Very unscientific, but
>very effective.

You sure it wasn't a convection oven? That was the standard thing for
baking for many years.

>I still have those old tapes, and the 2" was transferred to ADAT. They
>sounded fine after being "microwaved." I seem to recall being told
>that the transfer had to happen within a couple weeks, and then the
>tapes would lose their flux or something. I don't know; I never put
>them on the machine after I did the transfer, and I transferred within
>a day.

Baking just removeds the moisture, it does not solve the original problem that
causes the tapes to become hydroscopic. So they go gummy again after a week
or so. You can rebake them when this happens. I don't know how many cycles
you can really go through.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
October 20, 2004 3:35:48 PM

Archived from groups: rec.audio.pro (More info?)

On 20 Oct 2004 00:39:19 -0700, BobS@SingletonProductions.com (Bob
Singleton) wrote:
-----------8<--------------------------------
>AGFA/BASF admitted the problem and had a program in the 90's where
>they would pay for your tapes to be baked and transferred to the
>format of your choice. I called the company in Florida that had the
>BASF contract to find out how they handled the tapes, because I was
>familiar with baking the tapes in a convection oven, and was willing
>to do the transfers myself, rather than risk shipping them off and
>back.
>
>This is where it gets a little weird. The guy said that they
>microwaved the tapes. They removed the flanges and screws, and put
>them in a microwave at low power; 1/4" to 2" tapes; it didn't matter.
>
>I tried it. It worked great. The tapes came out smelling like they did
>when I first bought them, and the tape was very "relaxed," that is,
>even though they may have gone in the microwave with a nice, even,
>factory wind, they came out very loose. I had to be very careful with
>the 1/4" reels that they didn't unravel before I put the flanges back
>on.
>
>Now, that was the mid/late 90's when I did that. Don't ask me how long
>I baked them, or what brand microwave I used etc. I just recall
>putting the microwave on about 1/3 power, and doing it on a spinning
>platter until they felt warm and almost hot. Very unscientific, but
>very effective.
>
>I still have those old tapes, and the 2" was transferred to ADAT. They
>sounded fine after being "microwaved." I seem to recall being told
>that the transfer had to happen within a couple weeks, and then the
>tapes would lose their flux or something. I don't know; I never put
>them on the machine after I did the transfer, and I transferred within
>a day.
>
>I hope this is addressing the original question in the thread.
>
>Bob Singleton

Thanks for this information, Bob. Using a low-power microwave sounds
viable and I regard this as a sort of "Advanced Baking". The outcome,
that the wind had became very loose tells me that this must be a
humidity problem indeed; the microwave heating has done with it just
right -- better than a "normal", convexion baking -- and the formerly
swollen oxide returned to its dry thickness. If the temperature
developed wasn't all that high, I don't know why such a treated oxide
would lose its remanency. And yes, this can be regarded as being more
scientific than the ordinary "baking" <g>.

I have some AGFA DPR 26 tape on 7" reels and I've noticed a modest
shed at winding but I have no problems with playback. This is far of
being an oxide peeling problem yet. But still, they wind exceptionally
good and make a "factory new" wind every fast forward or rewind.

I let all sorts of old, dusty tapes being carefully fast wound through
a "Kleenex" tissue or similar. I warp a tape at the most convenient
spot on the tape path and start the winding. I control the pressure so
that the normal winding is not obstructed but the tape is still being
cleaned efficiently. It can help a lot, sweeping excessive oxide dust
away, enabling better tape to head contact and with sometimes quite
better reproduced high end. Doing so, one has to be cautious, though,
so as not to allow the running tape to touch anything as it can
scratch something immediately. Of course, if the oxide is peeling
away, you wouldn't do this.

Edi Zubovic, Crikvenica, Croatia
Anonymous
October 20, 2004 8:36:09 PM

Archived from groups: rec.audio.pro (More info?)

http://www.tapebaking.com/




"Scott Dorsey" <kludge@panix.com> wrote in message
news:cl5vkm$7gg$1@panix2.panix.com...
> Bob Singleton <BobS@SingletonProductions.com> wrote:
> >
> >I tried it. It worked great. The tapes came out smelling like they did
> >when I first bought them, and the tape was very "relaxed," that is,
> >even though they may have gone in the microwave with a nice, even,
> >factory wind, they came out very loose. I had to be very careful with
> >the 1/4" reels that they didn't unravel before I put the flanges back
> >on.
> >
> >Now, that was the mid/late 90's when I did that. Don't ask me how long
> >I baked them, or what brand microwave I used etc. I just recall
> >putting the microwave on about 1/3 power, and doing it on a spinning
> >platter until they felt warm and almost hot. Very unscientific, but
> >very effective.
>
> You sure it wasn't a convection oven? That was the standard thing for
> baking for many years.
>
> >I still have those old tapes, and the 2" was transferred to ADAT. They
> >sounded fine after being "microwaved." I seem to recall being told
> >that the transfer had to happen within a couple weeks, and then the
> >tapes would lose their flux or something. I don't know; I never put
> >them on the machine after I did the transfer, and I transferred within
> >a day.
>
> Baking just removeds the moisture, it does not solve the original problem
that
> causes the tapes to become hydroscopic. So they go gummy again after a
week
> or so. You can rebake them when this happens. I don't know how many
cycles
> you can really go through.
> --scott
> --
> "C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
October 20, 2004 10:02:46 PM

Archived from groups: rec.audio.pro (More info?)

Scott Dorsey wrote:

> IF you have a sticky-shed problem, this is different than normal
> shedding and you can tell because the stuff left on the heads
> is gummy rather than powdery, and it's sometimes even white
> rather than brown.

Agfa 369 will eventually get sticky-shed.

> If you have sticky shed issues, you will probably need to redo
> all of the splices with blue tape, if they were done with white
> tape.

Splices made with white schotch splicing tape has lasted well during
baking at some 50 degrees celcius for me.

> --scott


Kind regards

Peter Larsen

--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************
Anonymous
October 20, 2004 10:02:48 PM

Archived from groups: rec.audio.pro (More info?)

Mike Rivers wrote:

>> What can I do to prevent this? Obviously the tape has to be baked.

> No, it doesn't. and you shouldn't bake Agfa tape. It had an oxide
> shedding problem, but it's not the same "sticky shed" problem that's
> cured by baking.

Agfa 369 do - some of the time - develop sticky shed. They never did
have an oxide shedding problem in my household, I think you must be
thinking of PER525 - everybodys introduction to the pink sideo of tape
recording.

BASF's tapes were dusty new and they still are. To my knowledge that is
all that ails them.

> I'm really Mike Rivers (mrivers@d-and-d.com)


Kind regards

Peter Larsen

--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************
Anonymous
October 20, 2004 10:02:50 PM

Archived from groups: rec.audio.pro (More info?)

Evan Hill wrote:

> But I have to retract on my original statements. With further
> research, I noticed some of the AGFA tapes create the previously
> mentioned "holes" without baking.

It would then appear that the damage has already happened due to glue
that has oozed from the splice. That leads to the speculation that the
tapes may have been too tightly wound during storage and left untouched
for many years, possibly also in occasionally too hot or too varying
temperature.

> I thought maybe, instead of baking process, it was the process
> of fast rewinding them onto metal flanges from plasic flanges

As a sidenote, if an advantage of either flange type exists, then that
advantage is with the plastic reels, they are usually rounder and better
balanced.

> that created the mass oxide shed onto the backs of
> splices (blue tape, in case you were wondering). But even with slow,
> finger-on-the-flange hand winding (much slower than playback speed),
> the splices still stick and end up partly covered in oxide, creating
> those audible "holes."

They don't "stick", they have "stuck" already.

> What do I do now?

First fix your understanding of the problem, this appears to be
something that has happened already.

> The prospect of very, very slow winding doesn't
> seem like a viable option,

Wind until splice, stop prior to splice, investigate whether it is
possible to carefully pull the tape free of the rear side of the
splicing tape. Alcohol may be able to dissolve the glue from the
splicing tape and it will not wash the oxide off of the tape, so lifting
the tape and dabbing alcohol with a Q-tip may be the strategy to try.
Re-tape the splice with new 3M scotch splicing tape if available, it
could be relevant to bake first and re-tape later.

> as this is already a long project (5 more years worth of
> weekly shows),

Yees, but how many splices in each tape?

> and such slow winding would double or triple the work time.
> Plus this project is grant funded, and as we all
> know, grant money does not last forever.

Some of the time real world concerns win, so I have to ask the heretical
question: do those dropouts at all matter? - could it be that the
conclusion is that the only restoration avenue possible is to accept
them as damage that has taken place. It may be better to have
imperfections at each splice and the overall content safeguarded than to
try to salvage inches of audio at the risk of having to discard statute
miles of it later due to lack of time and/or funding.


Kind regards

Peter Larsen

--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************
Anonymous
October 20, 2004 10:02:52 PM

Archived from groups: rec.audio.pro (More info?)

Evan Hill wrote:

> So you say the tapes "shouldn't" be baked because it is
> just an oxide shed problem. Is there a reason they shouldn't
> be baked?

Mistaken/confused tape types. I learned that Agfa 369 too needed baking
because of reel of tape that stopped during playback, the tape was glued
to heads and guides by sticky shed goo.

> I've determined the dropouts were a winding and not a baking
> problem. Sticky shed or no, it seems that the baking process
> better adheres the oxide to the adhesive.

And? ... it is generally always possible to wind from reel to reel
directly, the wind may look messy, but it is OK for short term and you
can then rewind the tapes prior to baking them. I often choose to
re-lubricate my own tapes with silicone oil for car door rubber lists, I
don't know if there are reasons not to so do, but cleaning and relubing
tapes is very time consuming.

> Another more fundamental question: If the tape is losing enough oxide
> to affect accurate playback in 3 minutes, how does this amount of
> shedding affect the quality of the tapes for later playings?

Some loss, certainly some treble loss.

> What is being lost, in other words?

"Shine", but not content.

> Obviously, this question is less crutial
> because it's my job to preserve (and enhance in some ways) the

Be careful with the enhancing, it is a pestulence to discover that what
you did 20 years age when you restored something prevents you from
getting it better today.

> recordings in the state they are in right now by transfering them to
> another medium. I'm just curious for my own edification.

One should ask all the questions. Again, as I understand this, you have
encountered a problem that was caused by whomever that decided not to
rewind the tapes every other year as they should have been. It may be
better to live with it than to let it block the progress of the
safeguarding of the actual content of the archive.


Kind regards

Peter Larsen

--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************
Anonymous
October 21, 2004 1:49:34 AM

Archived from groups: rec.audio.pro (More info?)

In article <cl5vkm$7gg$1@panix2.panix.com> kludge@panix.com writes:

> Baking just removeds the moisture, it does not solve the original problem that
> causes the tapes to become hydroscopic. So they go gummy again after a week
> or so. You can rebake them when this happens. I don't know how many cycles
> you can really go through.

According to Bill Lund, former 3M tape guy, heating the tape to 130
degrees or so for several hours causes the binder to return to its
original chemical composition and it's good for quite longer than the
couple of weeks we've learned that baking is good for.

Someone had a theory (but I never learned why) that after some
(unnamed) number of cycles, something (also unnamed) happens and the
tape becomes useless.

Here's a fairly recent posting from Bill Lund to the Ampex list:

=========================

To say again what I have mentioned several times over the past couple
of years. Baking tape is a process whereby you bring one of the
chemical components of the magnetic dispersion up to a high enough
temperature to cause it to melt and slowly soak back into the
dispersion (magnetic coating) where it will tend to remain for quite
sometime. It probably wont help much to put it into a bag with
desiccant.

If you heat the tape to about 130 degrees and leave it there for about
12 hours and (most importantly) allow it to return to room temperature
VERY slowly (about another 12 hours) you will find that the tape will
remain playable for years to come. In fact, little difference (if any)
will be noticed between baked and new tape.

The key is to NOT be in a hurry. Do not be afraid to leave the tapes
in the oven for 12 hours or more and do not be in a hurry to bring
them to room temperature. Allow at least 24 hours for the entire
process, you will be glad you did.

3M tapes of the 226 family (226,227,806,807,808,809) responded
perfectly to this process, none of the others ever exhibited sticky
shed. The other thing to remember is if you hurry the process and they
become sticky again, you didn't a)get them to a high enough
temperature, b)didn't leave them in there long enough or c)tried to do
the process too quickly.

Remember, plastic reels will hold their shapes until about 160 degrees
F, metal reels are never a problem.

I see there are questions about 2" tape and the cool down period. Here
is what we found:

It is important that you make sure that the ENTIRE roll of tape
(regardless of width) reaches the target temperature (130 degrees F)
and remains there for around 12 hours. If you are doing 2" tape and
you are not sure that the entire reel reaches that temperature and
stays there for 12 hours, leave it in for 24 hours. Be very patient.
Do not hurry the process. 24 hours wont hurt 1/4 inch tape either.

If you are worried about print through, don't be. Print through is
related to the formulation of the tape NOT the temperature.
Temperature only allows it to reach it's maximum print through much
faster, but it wont make it worse. Cool temperatures just make the
tape take much longer to achieve the final print value.

Therefore if you have wider tape, leave it there for 24 hours and then
let it cool back to room temperature. Take it out of the oven and set
it on a shelf, and leave it UNDISTURBED for another 24 hours (this
will allow you to start another couple of rolls while the first set
cools.

Good Luck

Bill
3M tech service (ret)

================================

--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
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Anonymous
October 21, 2004 1:49:35 AM

Archived from groups: rec.audio.pro (More info?)

In article <41768C28.70612272@mail.tele.dk> SPAMSHIELD_plarsen@mail.tele.dk writes:

> Agfa 369 do - some of the time - develop sticky shed. They never did
> have an oxide shedding problem in my household, I think you must be
> thinking of PER525 - everybodys introduction to the pink sideo of tape
> recording.

I'm thinking of 468 and 469. If 369 ever made it over to this side of
the ocean, it certainly wasn't very popular so we don't have much
experience with it.


--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Anonymous
October 21, 2004 1:55:32 AM

Archived from groups: rec.audio.pro (More info?)

In article <znr1098314147k@trad>, Mike Rivers <mrivers@d-and-d.com> wrote:
>In article <41768C28.70612272@mail.tele.dk> SPAMSHIELD_plarsen@mail.tele.dk writes:
>
>> Agfa 369 do - some of the time - develop sticky shed. They never did
>> have an oxide shedding problem in my household, I think you must be
>> thinking of PER525 - everybodys introduction to the pink sideo of tape
>> recording.
>
>I'm thinking of 468 and 469. If 369 ever made it over to this side of
>the ocean, it certainly wasn't very popular so we don't have much
>experience with it.

We used 368 and 369, which were cheaper than 468, and which Direct To
Tape Recording in NJ used to sell at very reasonable prices. I have a
couple reels that did develop sticky shed, but much more mild than what
happened to 406 from the same era.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
October 21, 2004 2:38:41 AM

Archived from groups: rec.audio.pro (More info?)

Peter Larsen <SPAMSHIELD_plarsen@mail.tele.dk> wrote in message news:<41768C2A.D584A6BB@mail.tele.dk>...

> It would then appear that the damage has already happened due to glue
> that has oozed from the splice. That leads to the speculation that the
> tapes may have been too tightly wound during storage and left untouched
> for many years, possibly also in occasionally too hot or too varying
> temperature.

This is probably true, as I was told that until our building's tape
vault was built, these tapes sat in a hot, humid closet. Yikes...


> As a sidenote, if an advantage of either flange type exists, then that
> advantage is with the plastic reels, they are usually rounder and better
> balanced.

Well noted. The metal reels were needed for baking the tapes, since
the plastic will melt, or so I was told. I have determined that these
tapes definitely have a sticky shed problem. Unbaked, the playback of
the tape loses high frequencies in a matter of a couple minutes. Also,
the heads are left kind of gooey.


> Wind until splice, stop prior to splice, investigate whether it is
> possible to carefully pull the tape free of the rear side of the
> splicing tape. Alcohol may be able to dissolve the glue from the
> splicing tape and it will not wash the oxide off of the tape, so lifting
> the tape and dabbing alcohol with a Q-tip may be the strategy to try.
> Re-tape the splice with new 3M scotch splicing tape if available, it
> could be relevant to bake first and re-tape later.

The problem is I can't tell when a splice is coming. It is hidden in
the wind. Or maybe I'm missing something.


> Yees, but how many splices in each tape?

Was this a rhetorical question? If so, I don't understand. But in
actuality, there are about 9-15 splice per 20 minute tape.

> Some of the time real world concerns win, so I have to ask the heretical
> question: do those dropouts at all matter? - could it be that the
> conclusion is that the only restoration avenue possible is to accept
> them as damage that has taken place. It may be better to have
> imperfections at each splice and the overall content safeguarded than to
> try to salvage inches of audio at the risk of having to discard statute
> miles of it later due to lack of time and/or funding.

Point well taken. In fact, this has been my approach thus far. I was
just hoping I could preserve the "authenticity" of the tapes and have
to do as little digital editing as possible. Of course, even with
digital editing, there are some dropouts I cannot fix. (Just to
clarify, these "dropouts" are not silent spots. They are more like
cutting the top half of a waveform off, resulting in severe distortion
and loss of level.) So, I've been doing all that can be done, and
what's left is as close as it will get.

Thanks for your help,
Evan
Anonymous
October 21, 2004 10:05:23 AM

Archived from groups: rec.audio.pro (More info?)

> The problem is I can't tell when a splice is coming. It is hidden in
> the wind. Or maybe I'm missing something.
>

Incidentally, I wish wind wasn't a homograph.
Anonymous
October 21, 2004 1:24:34 PM

Archived from groups: rec.audio.pro (More info?)

In article <ff839d57.0410202138.77db2674@posting.google.com> wilsonrock@charter.net writes:

> > Wind until splice, stop prior to splice, investigate whether it is
> > possible to carefully pull the tape free of the rear side of the
> > splicing tape.

> The problem is I can't tell when a splice is coming. It is hidden in
> the wind. Or maybe I'm missing something.

Sure you can. But you have to sit there and watch the reels go around,
quite possibly at half speed. It's totally boring and extremely time
consuming. You (or whoever's paying the bill) make the call as to
whether it's worth it to try to save some of them or just let them go.

> actuality, there are about 9-15 splice per 20 minute tape.

That's not too many. It would take you maybe an hour and a half to
slowly wind the tape, locate each splice, try to get past it without
pulling the oxide off (and shrugging when you do), re-do the splice
with fresh tape, rewind, and play the tape to make the copy. Sure,
it's four times as long as playing and transferring, but if the
content is worth every attempt at preservation, then you have to take
the time. There are no shortcuts other than perhaps to spend an hour
teaching an intern to splice tape and put him to work while you're
doing something more productive and less boring.

> Point well taken. In fact, this has been my approach thus far. I was
> just hoping I could preserve the "authenticity" of the tapes and have
> to do as little digital editing as possible. Of course, even with
> digital editing, there are some dropouts I cannot fix. (Just to
> clarify, these "dropouts" are not silent spots. They are more like
> cutting the top half of a waveform off, resulting in severe distortion
> and loss of level.)

You're not going to fix that. If the recordings are stereo and a chunk
of oxide half the tape width comes off, you'll get a dropout on one
channel and not the other. I don't see how loss of a chunk of oxide
even across the full width of the tape could cause the top half of the
waveform to be cut off or to add distortion. Loss of level, for sure,
because there's less magnetism with oxide missing. I'm not doubting
what you hear, just how you describe it.


--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Anonymous
October 21, 2004 5:20:16 PM

Archived from groups: rec.audio.pro (More info?)

mrivers@d-and-d.com (Mike Rivers) wrote in message news:<znr1098362741k@trad>...

> > The problem is I can't tell when a splice is coming. It is hidden in
> > the wind. Or maybe I'm missing something.
>
> Sure you can. But you have to sit there and watch the reels go around,
> quite possibly at half speed. It's totally boring and extremely time
> consuming. You (or whoever's paying the bill) make the call as to
> whether it's worth it to try to save some of them or just let them go.

No, I really don't think I can. The splice is under another layer of
tape until I can see it. And by the time I can see it, the splice is
no longer underneith anything and the damage is already done, i.e. the
oxide has been pulled off of the layer of tape that was just above the
splice in the wind. Does that make sense? So, since the tape is stored
tails out and has to be rewound before being played, these dropouts
occur a second or so after the splice passes the heads. I understand
if this is hard to visualize.

XXXXXXXXXXXXXXX
XXXXSPLICEXXXXX
XXXXXXXXXXXXXXX

Each row of X's being a layer of tape in the wind on the reel, the
bottom being on the outside of the reel: It is the bottom row of X's
that becomes damaged, with the oxide being left on top of the splice.

> There are no shortcuts other than perhaps to spend an hour
> teaching an intern to splice tape and put him to work while you're
> doing something more productive and less boring.

I am the intern. I was hired on contract. I'm the only one doing this
project at this point.


> I don't see how loss of a chunk of oxide
> even across the full width of the tape could cause the top half of the
> waveform to be cut off or to add distortion. Loss of level, for sure,
> because there's less magnetism with oxide missing. I'm not doubting
> what you hear, just how you describe it.

I'm sorry, I poorly described it. The top half of the waveform is not
cut off, of course. But most of the time it is not the whole width of
the tape that is being pulled off. It is only chunks of either
channel. Where these chunks are taken out, there is often a pop,
sometimes along with a ripping sound (distortion across varying
frequencies), and it is apparent from looking at the waveform that not
all of the wave "information" is there. The point where the dropout
occurs is misshapen compared to the rest of the wave repititions (or
cycles, whatever). It can simply just be lower in level, but often
there are squared peaks and other malformations as well in the
waveform.

This is my purgatory.

Evan
Anonymous
October 21, 2004 6:35:44 PM

Archived from groups: rec.audio.pro (More info?)

Scott,

I have a 406 2" MRL tape with sticky shed (will stop my machine). Any
recommendations as to what I can do? I really need to get theis machine
calibrated (Otari MTR 90II).

Thanks,

Jerry



"Scott Dorsey" <kludge@panix.com> wrote in message
news:cl74uk$4n2$1@panix2.panix.com...
> In article <znr1098314147k@trad>, Mike Rivers <mrivers@d-and-d.com> wrote:
>>In article <41768C28.70612272@mail.tele.dk>
>>SPAMSHIELD_plarsen@mail.tele.dk writes:
>>
>>> Agfa 369 do - some of the time - develop sticky shed. They never did
>>> have an oxide shedding problem in my household, I think you must be
>>> thinking of PER525 - everybodys introduction to the pink sideo of tape
>>> recording.
>>
>>I'm thinking of 468 and 469. If 369 ever made it over to this side of
>>the ocean, it certainly wasn't very popular so we don't have much
>>experience with it.
>
> We used 368 and 369, which were cheaper than 468, and which Direct To
> Tape Recording in NJ used to sell at very reasonable prices. I have a
> couple reels that did develop sticky shed, but much more mild than what
> happened to 406 from the same era.
> --scott
>
> --
> "C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
October 21, 2004 6:35:45 PM

Archived from groups: rec.audio.pro (More info?)

Jerry Pillsbury <jerryp@cinci.rr.com> wrote:
>
>I have a 406 2" MRL tape with sticky shed (will stop my machine). Any
>recommendations as to what I can do? I really need to get theis machine
>calibrated (Otari MTR 90II).

Throw it out immediately.

The MRL tape is the _only_ reference that you have. Everything on the
machine is set up with respect to it. You do not want to even THINK about
using an MRL tape which is so bad that it's gone sticky. You don't even
want to use one that is a few years old and slightly deformed. Even a tiny
bit of mechanical deformation on the MRL will screw your azimuth up.

Get a new tape. If you don't have the money for the full tape with the tone
ladder, MRL will make you a short tape with just a few tones on it. If you
tell them that your old one went gummy, you might be able to try and get them
to knock the price down, but I doubt it.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
October 21, 2004 6:48:44 PM

Archived from groups: rec.audio.pro (More info?)

Thank you,

Jerry
"Scott Dorsey" <kludge@panix.com> wrote in message
news:cl8i2q$9ca$1@panix2.panix.com...
> Jerry Pillsbury <jerryp@cinci.rr.com> wrote:
>>
>>I have a 406 2" MRL tape with sticky shed (will stop my machine). Any
>>recommendations as to what I can do? I really need to get theis machine
>>calibrated (Otari MTR 90II).
>
> Throw it out immediately.
>
> The MRL tape is the _only_ reference that you have. Everything on the
> machine is set up with respect to it. You do not want to even THINK about
> using an MRL tape which is so bad that it's gone sticky. You don't even
> want to use one that is a few years old and slightly deformed. Even a
> tiny
> bit of mechanical deformation on the MRL will screw your azimuth up.
>
> Get a new tape. If you don't have the money for the full tape with the
> tone
> ladder, MRL will make you a short tape with just a few tones on it. If
> you
> tell them that your old one went gummy, you might be able to try and get
> them
> to knock the price down, but I doubt it.
> --scott
>
>
> --
> "C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
October 21, 2004 11:16:56 PM

Archived from groups: rec.audio.pro (More info?)

In article <4PPdd.6766$5v2.2690@fe2.columbus.rr.com> jerryp@cinci.rr.com writes:

> I have a 406 2" MRL tape with sticky shed (will stop my machine). Any
> recommendations as to what I can do? I really need to get theis machine
> calibrated (Otari MTR 90II).

Call MRL, tell them your tale of woe, and order a new calibration
tape. They used to give a discount on replacements if your tape failed
becuase it went sticky. I'm not sure they still do (since discovering
that ALL tape they used eventually got sticky) but you can ask.

If you don't want to spend the couple hundred bucks on a new tape,
spend a couple hundred bucks calling in a technician who has one.


--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo
Anonymous
October 25, 2004 8:53:36 PM

Archived from groups: rec.audio.pro (More info?)

Evan Hill wrote:

> No, I really don't think I can. The splice is under another
> layer of tape until I can see it. And by the time I can see it,
> the splice is no longer underneith anything and the damage is
> already done, i.e. the oxide has been pulled off of the layer
> of tape that was just above the splice in the wind. Does that
> make sense?

Hmm ... my splices never were so neat as not to be visible when looking
at the side of the reel, but some reels do not allow the view of very
much of the tape.

> So, since the tape is stored tails out and has to be rewound
> before being played,

It has to be moved from one reel to the other. It does not have to be
wound at full speed. As at least one person said there are machines out
there with adjustable winding speed. It may also be that a slow wind can
be obtained by blocking the light sensor on a semipro machine and set it
in play with the tape traveling directly from reel to reel, bypassing
all tape guides that can damage it by accumulating shed.

> these dropouts occur a second or so after the splice passes
> the heads. I understand if this is hard to visualize.

Not at all.

> XXXXXXXXXXXXXXX
> XXXXSPLICEXXXXX
> XXXXXXXXXXXXXXX

> Each row of X's being a layer of tape in the wind on the reel,
> the bottom being on the outside of the reel: It is the bottom
> row of X's that becomes damaged, with the oxide being left on
> top of the splice.

My head is constructed so that I see the outside of the real being on
the side of the upper x's and inner side on the side of the lower row.

> I am the intern. I was hired on contract.

What you say is that it is an unforeseen problem. You have also
repeatedly said that it is not a solvable problem. What remains to do
then is to make the customer aware of the issue and get approval of the
dropouts and then live with them. Again, this is damage that is already
done.

It is somewhat possible that the oxide will get stronger bound to the
tape by the baking, and it is also possible that more adhesive will ooze
from the splice during the baking. My guess is that baking first will
remedy the issue somewhat. From the general baking advice that has been
posted in this thread there is a reasonable temperature window between
the baking temperature and what plastic reels can survive.

> I'm sorry, I poorly described it. The top half of the waveform is not
> cut off, of course. But most of the time it is not the whole width of
> the tape that is being pulled off. It is only chunks of either
> channel. Where these chunks are taken out, there is often a pop,
> sometimes along with a ripping sound (distortion across varying
> frequencies), and it is apparent from looking at the waveform that not
> all of the wave "information" is there. The point where the dropout
> occurs is misshapen compared to the rest of the wave repititions (or
> cycles, whatever). It can simply just be lower in level, but often
> there are squared peaks and other malformations as well in the
> waveform.

> This is my purgatory.

Do nothing. leave the dropouts be - do not try to fix them
electronically or with software, you plain can not, and get the transfer
done. They are like hum's in a live recording ... not all problems can
be solved, nor should all problems be attempted solved.

Make whomsoever is the customer aware of the problem and that it is
unforeseen, uncureable and has happened prior to you getting the job so
that the customer will not be negatively surprised nor think that your
work is the cause OR re-negotiate the contract due to the unforeseen
problem, the risk of doing that being that whomsoever pays says .. ok,
it is lost, discard the lot.

If it is worth saving, then it is probably better to live with the
dropouts and get it done. I have most certainly not worried one
nanosecond on dropouts on a tape that finally got transferable after a
days work and a nights baking. I find it more constructive to be happy
that 99.995 percent transferred OK.

> Evan


Kind regards

Peter Larsen

--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************
!