Freezing coated paper

Alayne Alvis <alayne.alvis [at] sydney__edu__au> writes

>We have several 'coffee table' type books with glossy coated paper
>that requires freezing to deal with possible insect infestation.
>The possibility of damage to the paper from the freezing process has
>been raised. ...

It is not clear what effects to the paper you are alluding to here
but when I worked at the Canadian Conservation Institute (CCI) I
observed that during vacuum freeze-drying of some books on coated
paper, either the surface became powdery on drying, or large flakes
of the paper's surface (the coating) came off. I did not observe the
same thing happening if coated paper was frozen, then thawed. In the
case of the powdering, leaving the paper to equilibrate for about 24
hours seemed to reverse the phenomenon and the paper reverted to
being 'normal'.

I would think that the temperature at which paper is typically
frozen (often around -20 deg. C or more) would play a part in
whether the surface is affected or not.  I am not an expert in pest
management and the ways of eradicating pests but as I understand it,
this temperature (-20 deg. C) is typically what is considered to be
effective for killing insects or mould, so raising the temperature
above -20 deg. C may not be an option. Gradual freezing rather than
flash freezing, or treating with carbon dioxide may be other options
to be considered.

Please note that these are the personal observations of a retired
professional conservator and not those of the Canadian Conservation
Institute.

David Tremain (CCI, 1979 - 2010)


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                  Conservation DistList Instance 27:3
                 Distributed: Wednesday, June 26, 2013
                        Message Id: cdl-27-3-003
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