I only have anecdotal evidence that Charlie Richardson's suspicions may
be correct and it comes from the world of magnetic film:
The vast majority of magnetic film, as we all know, was a tri-acetate
base product and thus suffers from vinegar syndrome (VS) over time.
However, one of 3M's last offerings was a polyester base, back coated
product that yes, has the tendency to go SS. I have encountered the
problem more than once with that particular type of mag film and all of
it has been stored in the best of conditions. Other manufacturers
offered polyester base magnetic film stocks that were not back coated
and do not tend to go SS.
Corey Bailey Audio Engineering
On 12/20/2015 5:24 AM, Tom Fine wrote:
> I should also mention, Charlie wanted me to send the tape back after
> the first transfer for "further processing." I decided, no, I want to
> see how it holds up in the real (reel) world, over time, under
> non-vault storage conditions.
> -- Tom Fine
> ----- Original Message ----- From: "Jamie Howarth" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Saturday, December 19, 2015 10:54 PM
> Subject: Re: [ARSCLIST] One more sticky-shed data point - Richardson
> treated tape
> Very cool. Rad, scary, but if it holds up that's great.
> Please pardon the mispellings and occassional insane word substitution
> I'm on an iPhone
>> On Dec 19, 2015, at 8:54 PM, Tom Fine <[log in to unmask]> wrote:
>> Back in early 2014, I sent Charlie Richardson an old Ampex 7.5IPS
>> alignment tape, which is on Ampex 406 tape, circa 1970. The tape was
>> definitely sticky-shed, in fact the first couple of layers I wound
>> out by hand pulled oxide to the adjoining backing layer. Richardson
>> treated the tape with his "Rezorex" process, which apparently uses a
>> chemical peel to remove the back-coat layer, which Richardson
>> contends is the source point of sticky-shed. I transferred the tape
>> in May 2014 with no problems, then put it on a shelf in ambient
>> metro-NYC indoor environment. That first playback was on an Ampex
>> AG-440B. I just rewound and played the tape again, this time on an
>> Ampex 352. Still no sticky-shed evidence, and the audio was fine
>> (test tones were 10dB below reference tone, for the most part,
>> azimuth tones allowed stable adjustment). Richardson had left a
>> little bit of the end of the reel with the back-coat still on, and
>> that tape was solidly sticky-shed. I will keep on playing this tape
>> once a year to see if it goes sticky again.
>> I think a more scientific test of this process would require
>> sacrifice of both a sticky-shed test tape and a high-fidelity music
>> recording on sticky-shed tape. Although Richardson wants tapes not to
>> have been previously baked and played, which he contends damages the
>> tape, I'd want a reference transfer after one bake. Then let the
>> back-coat layer be removed, and do a transfer with the exact same
>> equipment and compare both measurements and careful listening, see if
>> the chemical peel does any sonic damage. In the case of my old test
>> tape, all I'm saying is that the tones are at the announced levels,
>> and this tape could be used in a pinch to align a tape deck, although
>> I'd want to bet on a modern MRL tape if it were for anything critical.
>> One other thing. The tape with the backcoat removed is not as thin as
>> I thought it would be. It seems to move through the transport just
>> fine. I didn't observe any obvious edge-curl or country-lane motion,
>> and it fast-winds just fine through all the static guides on an older
>> Ampex transport.
>> I'd want to do more testing with very familiar high-fidelity music
>> recordings to make sure the process doesn't do any damage to audio,
>> but for at least a year and a half, it does seem to prevent a return
>> of sticky-shed's mechanical symptoms.
>> -- Tom Fine