Cold storage for polyester base magnetic tape

In reviewing specification for cold storage of polyester based
magnetic tape, I have come across the following:

    ISO 18923:2000 Imaging materials--Polyester-base magnetic
    tape--Storage practices "Tape should not be stored below 8 deg.
    C due to a potential problem with lubricant separation from the
    binder" (p5)

    IPI Media Storage Quick Reference "Separation of the lubricant
    from the binder layer is possible when the tape is stored at
    temperatures below 11 deg. C" (p7)

    IPI Media Storage Quick Reference wheel:  Storage at 4 deg. C is
    "fair"--that is "does not meet ISO recommendations but may be
    satisfactory for extended periods of time." Cites ISO 18923 and
    ISO 18933.

I have not yet reviewed the second citation in the last reference
(ISO 18933:2006 Imaging materials--Magnetic tape--Care and handling
practices for extended usage) and am hesitant to purchase it without
knowing that it accounts for the difference between the ISO 19823
recommendation and the IPI recommendation. Can anyone shed light on
the two different minimum temperatures given as a the point at which
lubricant separation becomes a problem, as well as the ISO standard
seeming to indicate an 'absolute' minimum, vs. the IPI
recommendation which indicates that storage "may be satisfactory"
below this point?

Katie Mullen
Preservation Coordinator,
Library-Archives
Wisconsin Historical Society
816 State Street
Madison WI 53706-1482
608-264-6489


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                  Conservation DistList Instance 25:9
                 Distributed: Thursday, August 4, 2011
                        Message Id: cdl-25-9-024
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