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ARSCLIST  January 2016

ARSCLIST January 2016

Subject:

Re: One more sticky-shed data point - Richardson treated tape

From:

Shai Drori <[log in to unmask]>

Reply-To:

Association for Recorded Sound Discussion List <[log in to unmask]>

Date:

Thu, 21 Jan 2016 03:41:04 +0200

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (255 lines)

Hi Tom
Just a clarification. My problem was with the 206 and 207 but was that it
delaminated.

Cheers
Shai Drori
Expert digitization services for Audio Video
Hi Res scanning for film 8mm-35mm
www.audiovideofilm.com
[log in to unmask]

On Thu, Jan 21, 2016 at 3:33 AM, Tom Fine <[log in to unmask]> wrote:

> 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".
>>>
>>
>>
>>

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