Books with blocked pages

Diana Ruby-Sanderson <dlrs<-a t->rmh< . >com>

>Recently, we discovered in our Philadelphia office a shelf of books
>that had been damaged in a small water disaster.  Whoever cleaned up
>did not realize that the books were soaked and simply moved them to
>another shelf where they dried.  Now, the pages are literally welded
>together.

Although not actually mentioned in the request, I presume the books
were on coated paper.  Most book and paper conservators generally
agree that unless coated paper is dealt with within 6 - 8 hours, it
will end up blocked or stuck together.  Once stuck together, no
amount of rewetting will separate them. The books must first be
placed in a freezer then vacuum freeze-dried;  vacuum (thermal)
drying, where heat is involved, is not generally recommended as it
can cause blocking and/or solubility of inks.

The UNESCO RAMP study published in 1987 by John McCleary "Vacuum
Freeze-Drying, A Method to Salvage Water-Damaged Archival  and
Library Materials" gives a good explanation of what is happening
when coated paper dries and sticks together (pp.4; 6).   Cunha and
Fischer published a couple of articles in 1977 in "Preservation of
Paper & Textiles of Artistic Value" American Chemical Society,
Advances in Chemistry series, 164, Ch. 7, Ch. 8 on experimental work
on one type of coated and one uncoated paper, where Fischer found
that paper that was loosely stacked didn't stick as quickly as that
which was compressed (in the experiments, under weight, but in
reality the sort of compression found in a closed book on  a shelf).

The only time I have been able to separate wet coated paper is
within the 6 - 8 hour period before the paper became so saturated
that the filler (or coating or loading) became soluble then started
to dry and fuse to adjacent pages. In that particular case it was
possible to interleave the pages and air-dry.  Air-drying is not a
normally a recommended practice because it doesn't often work,
usually because you can't get to them in the amount of time required
for it to be effective.

So, I hate to say it, but I don't think there is anything that can
be done to separate these  pages.  Any attempt to physically
separate the pages (i.e. with a spatula) will result in damage to
the paper and loss of text.

This fits in nicely with an enquiry I'm currently dealing with.  As
far as I can find, there have been few scientific studies in recent
years on the effects of freeze-drying on different types of paper,
and would welcome people's experiences in dealing with freeze-drying
paper, and thoughts on whether a new project needs to be done on
this subject.  Maybe this is something that might come up at  the
AIC  disaster conference next year.

David Tremain
Conservator, Preventive Conservation Services
Canadian Conservation Institute
613-998-3721
Fax: 613-998-4721

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                  Conservation DistList Instance 11:49
                Distributed: Wednesday, December 3, 1997
                       Message Id: cdl-11-49-002
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