Hi Richard:

In your point (d), are you agreeing with my theory that sticky-shed tapes will go sticky no matter
how they are stored? Also, do you think they go back to being sticky after being baked, now matter
how they are stored? I think yes to both questions, based on experience, which is why I think it's
foolish to go to the expense of a super-low-humidity storage environment in an effort to "remedy"
sticky-shed. And, if that's not the reason for super-dry, then what else, especially since it seems
(again from personal experience) to ruin acetate-backed tapes.

Regarding John Haley's post, my northeastern US indoor environment varies from about 50% humidity in
the winter (it can go lower on days where it's bone-dry outside and the hot water heating system is
on full bore) to about 60% in the summer (some days requiring the dehumidifier because the concreate
slab "sweats" if it's hot and humid enough). That doesn't seem like a massive variance that would
ruin magnetic media quickly. Ideally, if I wanted to spring for a robust climate-control system, I'd
probably opt for around 55% humidity and 65 degrees all the time. That seems to be the most
comfortable indoor working environment and equipment seems to like it best. It also seems to be good
for keeping static charges under control.

-- Tom Fine

----- Original Message -----
From: "Richard L. Hess" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, April 17, 2013 4:29 PM
Subject: Re: [ARSCLIST] remanence decay and tape aging


> Shai,
>
> Jay "MRL" McKnight actually has a paper looking at what might be a "safe" field.
> http://home.comcast.net/~mrltapes/field-strength-for-partial-erasure.pdf
> (I don't see it currently indexed on his HTML, but Google found it)
> and the IASA has a report and I'll leave the exercise to the student converting units
> between Jay's paper and the IASA report.
> http://www.iasa-web.org/magnetic-fields/influence-recorded-tape
>
> John,
>
> Thanks for the kind words about my paper and website. I have a slightly different mental model of
> what you're describing:
> (a) Temperature and humidity and especially the cycling thereof is not good for tapes.
> (b) Tom Fine postulates (and I tend to take this seriously) that too-low humidity such as that
> recommended for storing tapes subject to SSS is very bad for acetate tapes.
> (c) The binders that are extremely subject to degradation based on normal room temperature
> heat/humidity were improper applications/designs or poorly/incompletely reacted during
> manufacture.
> (d) While storage conditions play a role, there are tapes with inherent vice that will
> self-degrade far more rapidly than other tapes. This "vice" was built-in during the
> design/manufacture process.
> (e) Tape type numbers are only a loose approximation for identifying tape chemistries
> (f) Lot-to-lot variations can be VERY substantial even within the same chemistry.
>
> Cheers,
>
> Richard
>
> On 2013-04-17 3:42 PM, John Haley wrote:
>> I just read your 2008 tape article from ARSC Journal, Richard, and looked
>> at your website, thanks very much for sharing all this valuable info you
>> have collected about the vicissitudes of various tapes. I have not seen
>> this much good collected empirical info anywhere else. You're the man!
>>
>> I have always assumed that in addition to things that happen resulting from
>> manufacture, tapes are highly affected by things like heat and humidity
>> during the years that they have been stored. A household in the Northeast
>> that does not run a humidifier in the winter can get far dryer than the
>> Sahara desert, to the detriment of everything in the house--furniture,
>> wood, living things and things made from chemicals, like tapes.
>>
>> Thanks,
>> John Haley
>>
>>
>> On Wed, Apr 17, 2013 at 3:06 PM, Shai Drori <[log in to unmask]> wrote:
>>
>>> Jay I assume from MRL? If so, he has a little leaf he hands out with every
>>> test tape he sells, that is a very interesting read. In short, he claims
>>> (and I believe it) that the tapes are very robust and that if you read
>>> through his description you realize that it takes a very strong magnetic
>>> field to erase a tape.
>>> Shai
>>> בתאריך 17/04/13 7:01 PM, ציטוט Richard L. Hess:
>>>
>>> Hello, Gregorio,
>>>> In general, the magnetic record seems to be rather robust and it mostly
>>>> decays from close encounters with magnetic fields stronger than the
>>>> Earth's. I know of no studies that have attempted to quantify this, but I'm
>>>> copying Jay McKnight who may know of a study and if he has any information,
>>>> I'll post it to the list.
>>>>
>>>> So, assuming no chemical or physical degradation (which mostly affect
>>>> tape via spacing loss across part or all of the tape) and no close
>>>> encounters of the strong magnetic kind, the S/N decay rate would be minimal
>>>> (I don't want to say zero, but I suspect close to it).
>>>>
>>>> We had the discussion on the Studer list about whether tape or machine
>>>> background noise is predominant and Jay chimed in with an "it depends". For
>>>> master tapes, generally the tape noise is predominant. There are times at
>>>> slower speeds and narrower tracks where head/electronics noise would be
>>>> predominant.
>>>>
>>>> As to degradation factors, I have a page I try and keep updated where
>>>> this is discussed.
>>>>
>>>> http://richardhess.com/notes/**formats/magnetic-media/**
>>>> magnetic-tapes/analog-audio/**degrading-tapes/<http://richardhess.com/notes/formats/magnetic-media/magnetic-tapes/analog-audio/degrading-tapes/>
>>>>
>>>> I hope this helps a bit.
>>>>
>>>> Cheers,
>>>>
>>>> Richard
>>>>
>>>>
>>>> On 2013-04-17 12:32 PM, Gregorio Garcia Karman wrote:
>>>>
>>>>> Dear members,
>>>>>
>>>>> I am looking for references in the literature dealing with the study of
>>>>> the decay of magnetic remanence as an effect of tape aging. What is the
>>>>> expected signal-to-noise decay rate under ideal conditions (i.e. no
>>>>> chemical degradation)? In real life, what is your experience in regard to
>>>>> different brands / models in similar storage conditions?
>>>>>
>>>>> Thanks in advance and regards
>>>>>
>>>>> Gregorio
>>>>>
>>>>
>>> --
>>> בברכה,
>>> שי דרורי
>>> מומחה לשימור והמרה של אודיו וידאו וסרטים 8-35 ממ.
>>>
>
> --
> Richard L. Hess email: [log in to unmask]
> Aurora, Ontario, Canada 647 479 2800
> http://www.richardhess.com/tape/contact.htm
> Quality tape transfers -- even from hard-to-play tapes.
>