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Subject: Thermaline cryogenic drying

Thermaline cryogenic drying

From: Barbara Cattaneo <barbaracattaneo>
Date: Tuesday, April 17, 2001
Has anybody heard of "Thermaline", cryogenic drying method for water
damaged rare and valuable books and document, also adopted for
parchment and leather? This method is briefly described in NEDCC
technical leaflets, in the section dedicated to disaster recovery.
Is it an evolution of freeze drying? How does it work exactly?

    **** Moderator's comments: Please see
    <URL:> for information on
    the process.

    We used it here for our last flood (see
    <URL:> for some
    background on that event), with very great success. (There's a
    chance this URL is limited to Stanford access; if so, I assume
    someone will let me know, and I'll make the resources available
    somewhere else)

    The process is in essence vacuum freeze-drying, but with the
    temperature kept very close to the triple point so there is
    (possibly) a very brief liquid phase, and drying under restraint
    (to a higher moisture content than the bone-dry endpoint of
    ordinary vacuum freeze-drying) to reduce planar distortion, and
    as a result significantly reduce the amount of rebinding needed.
    The cost appears to be high, but when you factor in reduced
    rebinding costs it can be quite competitive.

    Walter Henry
    Preservation Dept
    Stanford University Libraries

Barbara Cattaneo

                  Conservation DistList Instance 14:55
                 Distributed: Thursday, April 19, 2001
                       Message Id: cdl-14-55-028
Received on Tuesday, 17 April, 2001

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