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Tom:

Didn't mention Richardson's method because I haven't used it and have no
test data to supply.  At this point, we have other methods that work.  The
only tapes we can't consistently restore are those where the recording layer
has fallen off the base coat.  We do have a method that can salvage some of
these tape if treated before the oxide is actually missing and is just loose
Unfortunately, this only works about 50% of the time and if the oxide is
already gone, not much anyone can do about it.  The method is , once again,
an application of basic polymer science, just a different approach- no
baking involved.


Peter Brothers
SPECS BROS., LLC
973-777-5055
[log in to unmask]
Audio and video restoration and re-mastering since 1983





-----Original Message-----
From: Association for Recorded Sound Discussion List
[mailto:[log in to unmask]] On Behalf Of Tom Fine
Sent: Wednesday, January 20, 2016 8:33 PM
To: [log in to unmask]
Subject: Re: [ARSCLIST] One more sticky-shed data point - Richardson treated
tape

Hi Peter:

Once again, very useful info. Thanks for taking the time.

Interesting to know so many different formats of tape get hydrolysis. As I
said, in the cases I cited, baking made the tapes playable, so that's what
it must be. Including the TDK DATs.

You're being very specific about not mentioning Richardson's method. Have
you tested it in your laboratory? I will definitely keep this forum informed
about how my treated tape does over time, but my testing is unscientific. I
just play the thing once a year and see if it leaves residue, and compare
the output to previous captures, which is really not scientific either
because tape machines get used all year and there's no guarantee that the
heads and electronics are working exactly the same each time the tape is
played. I will say that no sticky tape I've had except this one stayed
un-sticky 1+ year after treatment. All previous treatment was traditional
baking.

-- Tom Fine

----- Original Message -----
From: "lists" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, January 20, 2016 4:50 PM
Subject: Re: [ARSCLIST] One more sticky-shed data point - Richardson treated
tape


> Hallo again:
>
> LOL does not respond well to baking.  If the lubricant is gone, it is
gone-
> baking will have no effect.  If the lubricant has crystalized, the
crystals
> will melt near room temperature- again, no reason to bake. Note; both
> assertions backed up by laboratory testing.   If you are baking standard
> audio cassettes successfully, they probably have some degree of
hydrolysis.
> It appears somewhat different as the binder is thinner (less binder to
> decay), the interface between the tape and heads is smaller (less surface
> for frictional problems to be noticed) and many of the cassettes are not
> backcoated (less tendency to hydrolyze so less oligomer residue).  We have
> encountered many audio tapes with hydrolysis.  The effects on the tape
just
> appear different than on larger tapes.  It is one of the reasons I'm not
> particularly fond of the popular term "sticky shed" when the actual
problem
> is "binder hydrolysis".  Hydrolysis can easily cause tapes to have a
higher
> frictional coefficient without significant, visible shedding.   Ok,
"sticky
> shed" sounds way cooler but it can obscure the actual chemical reaction
that
> is happening and result in incorrect assumptions.  If your audio tapes
jam,
> stick or run slow in your machinery and respond to "baking", the problem
is
> much more likely to be hydrolysis than LOL.
>
> As for video tape, nearly all 1/2" open reel videotapes now exhibit
> hydrolysis to some degree.  The majority of 3/4" video made between 1975
and
> 1985 also exhibit hydrolysis (ok, Il use "sticky shed").  Many Ampex 3/4
> from this era are so bad that, when put in the playback machine, they
almost
> immediately seize up and will not move.  1" and 2" videotape also
frequently
> have sticky shed.
>
> DATs, in my experience, not so much.  Yes DATs have problems but we have
> been able to restore DATS to playable condition by cleaning and polishing
> the tape surface- no baking.  The DATs are shedding and won't play back
> properly but we have found they don't need baking- they seem to  just be
> falling apart.  There is also a problem with the load mechanism in many
DAT
> machines that goes slightly out of alignment very easily and abrades the
> tape during playback transport, causing additional shedding.  None of the
> DAT info here is backed up by laboratory testing; just my experience.  If
> others have had success with baking, there may be a hydrolysis issue.  We
> may have just overcome the minor hydrolysis on the surface with the
cleaning
> and polishing.
>
> Finally, a few thoughts on signal loss with baking.  It is possible that
> baking might cause some irregularity on the tape surface.  I haven't seen
> laboratory evidence of this, however, and we always clean tapes after
baking
> them so any irregularities would likely be smoothed out.  I have seen tape
> under electron microscope[e that clearly shows tape surfaces are rougher
> right after manufacturing than they are after a few record/playback
passes.
> I have always been amazed that there is no conclusive laboratory evidence
> for the audio loss.  Everything is hearsay but it really should not be
that
> hard to set up an easily repeatable and fairly inexpensive test for this.
>
> Another possibility is "thermal idiots".  Nice technical term but, hey,
the
> technical name for the insulating powder added to high density magnetic
> recording mediums to counter superparamagnetic effects is "Pixie Dust".
In
> any case, the magnetic particles on many older analog tape had a wide
range
> of coercivity and retentivity.  This is one of the reasons for
print-through
> where the lower coercivity pigments get affected by the magnetic field
from
> pigments in adjacent wraps.  Heat is also well known to weaken magnetic
> characteristics of many materials (including those the magnetic pigments
are
> made of).  If low retentivity pigments are subject to heat, it is quite
> possible they will lose or have the magnetic moment on the pigment
effected.
> This is one of the ways print through is treated- the tape is
wound/rewound
> and the low coercivity/ low retentivity pigments that picked up the print
> through are scrambled by the combination of the mechanical shock from
> transport as well as the  heat generated by the transport friction; and
the
> print through is reduced.  Just an idea as far as possible loss of signal
> during "baking" is concerned, but it is consistent with magnetic theory.
> This doesn't mean I am asserting that this is what is happening, as we
> haven't seen a problem with signal loss, but it does match the science-
now
> we just need someone to do some controlled testing.
>
>
>
> Peter Brothers
> SPECS BROS., LLC
> 973-777-5055
> [log in to unmask]
> Audio and video restoration and re-mastering since 1983
>
>
>
>
>
> -----Original Message-----
> From: Association for Recorded Sound Discussion List
> [mailto:[log in to unmask]] On Behalf Of Tom Fine
> Sent: Wednesday, January 20, 2016 3:01 PM
> To: [log in to unmask]
> Subject: Re: [ARSCLIST] One more sticky-shed data point - Richardson
treated
> tape
>
> Hi Lou:
>
> I agree, having transferred 1000+ cassettes over the years, that what we
> call Sticky Shed has never cropped up. However, there have been cases of
> Loss of Lubricant (LOL) or something similar, which has rendered the
> cassette unplayable without baking. Baking has worked for me every time.
> I've encountered this mostly with black-oxide off-brand cassettes, circa
> 1980s and early 1990s, some of which have been mass-duped (ie
professionally
> duped and packaged for mass-market release).
>
> The other thing I have encountered, mainly with Scotch brand CRO2 tapes
> circa 1980s and late 1970s, is terrible warpage that leads to the tape
pack
> sometimes being too big to fit in the shell. My solution to this has been
to
> very carefully hand-wind enough of the tape-pack over to one side so both
> sides move comfortably in the shell, then splice one side into a new
> cassette housing, transfer both tapes and edit together in the proper
> sequence in the DAW.
>
> By far the biggest problem I have encountered with cassettes is the
pressure
> pad having come unglued. I generally transplant those tapes into a new
> shell. You can still find screw-together C-0 cassette shells out there for
> sale, but I usually use one of hundreds of old Maxell and TDK tapes I've
> accumulated into a big box, just for that purpose.
>
> There has been talk out in the video world, some of it on the Ampex List,
> about certain videotape brands that develop Sticky-Shed and/or LOL. There
> are definitely some DAT types that develop something that makes them gooey
> and non-playable. I've enountered this with TDK brand DAT tapes, and
baking
> has made them playable.
>
> When Telarc Records was reissuing their Soundstream recordings, which were
> on 1/2" instrumentation tapes, standard practice was to bake the tapes in
a
> convection oven. I don't know exactly what brand and type tapes they used.
I
> don't know enough about reel to reel digital tape systems to know if DASH
> tapes need baking.
>
> What is still mysterious to me is why some tapes of a type not known for
> sticky-shed will go sticky.
> For instance, Shai has reported all kinds of problems with Scotch 206 in
> Israel. I've never had one sticky 206 tape here in the US northeast. And
the
> same with vinegar syndrome. Some people report never having problems with
> Scotch 111, yet my experience is about 50-50 whether a tape will go
vinegar
> and start edge-curling or not. Audiotape acetate-backed seems less likely,
> but I've sure encountered my share of those tapes going vinegar. And yet
> almost all types of 35mm acetate-backed audiofilm will go vinegar.
>
> -- Tom Fine
>
>
> ----- Original Message -----
> From: "Lou Judson" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Wednesday, January 20, 2016 2:36 PM
> Subject: Re: [ARSCLIST] One more sticky-shed data point - Richardson
treated
> tape
>
>
> Here's a slightly offtopic question. I shared the post of Peters' with an
> associate, with whom I am
> involved in a restoration project involving cassttes tapes from the 70s
> through the 1990s. We are
> wondering why audio cassettes are so rarely having sticky-shed problems. I
> know that has been
> discussed occasionally here, but why are cassetes relatively immune?
>
> <L>
> Lou Judson
> Intuitive Audio
> 415-883-2689
>
> On Jan 20, 2016, at 10:33 AM, lists <[log in to unmask]> wrote:
>
>> Hello all:
>>
>> Coming very late to this thread.  I don't intend to talk here about Mr.
>> Richardson's process but, in answer to Tom's post, I'll try to address
> some
>> of the issues with "sticky shed".
>
>