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It does look a bit more crystalline in the magnified image. I'd say it is
probably a by-product of the deterioration of the urethane binder, or
possibly the remnant of lubricant or release compounds used in the
manufacture of the tape. I've seen similar deposits on other formats,
although more obviously crystalline to the naked eye.

Steve

Steve Greene
Audiovisual Archivist
Office of Presidential Libraries
National Archives and Records Administration
(301) 837-1772


On Thu, Jul 24, 2014 at 8:34 AM, Karl Fitzke <[log in to unmask]>
wrote:

> Tom,
>
> Thanks very much for your continued interest and suggestions.  Same goes
> for George Blood, Richard Hess, Malcolm Rockwell, Seva at soundcurrent, Tre
> Berney, and Steve Green.
>
> I can't find out anything about the long term storage of this tape.  Will
> ask archivists where it was made later today.  I really should learn how to
> use our Accessions program myself! Interesting to note on Byne's disease
> wikipedia page that wood esters could cause that.  Perhaps left in a wooden
> drawer or case for many years?
>
> We are trying to get access to mass spectrometry at Cornell and nail down
> the chemical composition.
>
> Then we'll clean some and try playing them.  Will be interested to see if
> salt is only at edges of tape or growing on surface as well.  So far, I've
> only tried to lightly brush some of the stuff off (dry) with little to
> moderate success.  Isoprop, as you suggest, may likely be the next step.
>
> -Karl
>
> On 7/23/14 8:32 PM, Tom Fine wrote:
>
>> Hi Karl:
>>
>> Do you know the history of this tape? Was it made in a rain forest or
>> some other extreme environment? Maybe stored someplace very humid for some
>> period of time? I'm wondering if there was a reaction between the slip
>> sheet and the tape, which caused salt crystals to form.
>>
>> My suggestion -- carefully scrape off some of the white stuff, and keep
>> the slip pad. Then, carefully clean the outside of the tape pack with
>> isoprop and re-shell the tape. Then, make your transfers. My bet is, the
>> tape will play just fine. There might be some crud on the heads or, more
>> likely, the pinchroller.
>>
>> Separately, get one of your Cornell colleagues to do some chemistry
>> research on the white stuff you scraped off. It would be interesting to
>> know exactly what it is, and hear a chemist's speculation on what produced
>> it.
>>
>> -- Tom Fine
>>
>> ----- Original Message ----- From: "Karl Fitzke" <[log in to unmask]
>> >
>> To: <[log in to unmask]>
>> Sent: Wednesday, July 23, 2014 7:17 PM
>> Subject: [ARSCLIST] White Tape Contaminant Part 2 corrected photo link
>>
>>
>>  Sorry, I sent the wrong photo link earlier this afternoon and you were
>>> likely locked out.
>>>
>>> Please try this:
>>>
>>> https://cornell.box.com/s/rafx7ue412ylu7svl0j6
>>>
>>> Best wishes,
>>> Karl
>>>
>>> --
>>>
>>> Karl Fitzke
>>> Audio Engineer
>>> Macaulay Library
>>> Cornell Lab of Ornithology
>>> 159 Sapsucker Woods Road
>>> Ithaca, NY 14850
>>>
>>> 607-254-1100
>>>
>>> [log in to unmask]
>>>
>>> Our Mission:
>>> To interpret and conserve the Earth's biological diversity through
>>> research, education, and citizen science focused on birds.
>>>
>>>
>>>
> --
>
> Karl Fitzke
> Audio Engineer
> Macaulay Library
> Cornell Lab of Ornithology
> 159 Sapsucker Woods Road
> Ithaca, NY 14850
>
> 607-254-1100
>
> [log in to unmask]
>
> Our Mission:
> To interpret and conserve the Earth's biological diversity through
> research, education, and citizen science focused on birds.
>