Print

Print


Maybe Peter does not know about Richardson's method Tom - it might be 
worth explaining briefly as it is a unique concept.

Regards,

John Schroth
MTS

On 1/21/2016 3:36 PM, lists wrote:
> 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".
>>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 2016.0.7357 / Virus Database: 4522/11452 - Release Date: 01/21/16
>
>