Storage environment for parchment

What are the recommended temperature and relative humidity (or
published standards) for storing bound and unbound vellum and
parchment library material?  Trolling the Internet and available
books I come up with only two references.  Etherington and Roberts
(1982) recommend "temperatures between 0-20 deg. C (32-68 deg. F),
with a relative humidity of 50 to 65%." (The RH seems to too high to
me as well as the upper end of temperature.)

A 1992 JAIC article states "At 30% RH, a cyclic variation of +/- 5%
can be permitted with minimal effects of swelling and shrinkage."
(There is no mention of temperature in this article and,
importantly, it concerns only modern vellum, not the type of objects
in special collections.)

    Eric F. Hansen, Steve N. Lee, and Harry Sobel.
    "The Effects of Relative Humidity on some Physical Properties of
    Modern Vellum"
    JAIC 1992, Volume 31, Number 3, Article 5 (pp. 325 to 342).
    <URL:http://cool.conservation-us.org/
        jaic/articles/jaic31-03-005.html>

Princeton is going to be expanding its special collections vaults
and the manuscripts curator asked about the appropriate conditions
for the storage of vellum and parchment in his collections.

    **** Moderator's comments: The above URL has been wrapped for
    email. There should be no newline.

Robert J. Milevski
Preservation Librarian
Princeton University Library
One Washington Road
Princeton, NJ 08540
609-258-5591


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                  Conservation DistList Instance 23:25
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