The best written information that I am aware of on the freezing technique
was written by Mary-Lou Florian, Conservation Scientist at the British
Columbia Provincial Museum. It was published in the Leather Conservation
News, Volume 3 Number 1 Fall 1986. It is approximately 13 pages long. The
Leather Conservation News was a bi-annual publication of the Materials
Conservation Laboratory, Texas Memorial Museum and affiliated with the ICOM
Committee for Conservation's Working Group: Conservation of Leathercraft
and Related Objects. The 1986 publication indicates the following address:
LCN, Materials Conservation Lab, BRC 122, 10100 Burnet Rd., Austin, TX
78758 USA.
I don't know if a copy is available through them or if there is any other
research or publications on the subject. I do have a copy and may be able
to send one to those in need of it.

However, the following is extracted from this article, entitled "The
Freezing Process - Effects on Insects and Artifact Materials"

"Conclusions and a synthesis of the information leads to the following
procedure recommendations:  Artifacts containing non-absorbent or wet
materials should not be processed in a constant temperature chest freezer.
        1.  When using a chest freezer, infested artifacts should be bagged
in airtight clear polyethylene film, and partially evacuated, the amount
depending on the stability of the artifacts and its tolerance to the
pressure of the film against it. When using a controlled temperature and
humdity freezing chamber, bagging is not necessary. Precautions should be
taken when bagging infested materials, because as soon as the artifact is
in the bag, insects will respond to the environmental change and try to
escape, therefore seal immediately.
        2.  When using a chest freezer, if the artifact is large (i.e.
furniture), pretreated silica gel or absorbent materials can be included
with the artifact in the bag to absorb the excess water due to cooling of
the air around the artifact and to maintain a relative humidity below 100%.
        3.  Bagged and infested materaials should be kept at room
temperature (above 18 degrees C) until placed in the freezer. In an
emergency, they may be placed in a refrigerator until freezer space is
available, but should not be temproarily stored in a cold basement or cold
storage with temperatures above 5 degrees C.
        4.  There should be adequate air circulation around the artifact to
allow it to cool to at least 0 degrees C in four hours.
        5.  Thermo-couples should be used to record the time/temperature
parameters of the freezing procedure, i.e. the rate of cooling and thawing,
and the time at the minimum temperature of the artifact.
        6.      The minimum temperature has been established at -20 degrees C.
        7.      The time span at the minimum temperature has been
established at 48 hours.
        8.      A slow rate of thawing is desirable, i.e. when the rate of
increase of temperature cannot be controlled, place materials directly from
the freezer into a refrigerator or cold storage and leave there until
thawed; or slowly increase the temperature  of the freezer up to 0 degrees
C over a period of 8 hours (arbitrary).
        9.      It is desirable to immediately repeat the freeze-thaw cycle.
        10.     If possible, leave artifacts in the polyethylene bag for
storage. Do not remove the bag until the artifact has reached room
temperature and there is no condensed water on the outside of the bag.
Insect remains should be removed if present.
        11.     A record of all the above procedures should be made and
included with the condition report for the artifact. The record should
include: identification, stages, and activity of the insect; packaging
materials and method; time required to bring materials to 0 degrees C and
to minimum temperature; time materials were held at minimum temperature;
time required to bring materials to room temperature; any physical changes
observed; and the success of the procedure."

Alice Hoveman, History Curator (and former conservator)

Alice R. Hoveman
History Curator
Redding Museum Of Art & History
P.O. Box 990427
Redding, CA  96099-0427
voice: (916) 243-8801
fax:   (916) 243-8929
e-mail: [log in to unmask]
Redding Museum Web Site: http://www.shastalink.k12.ca.us/www/rmah/RMAHmain.html