Paper damaged by seawater

Kaname Shimada <shimada [at] hozon__co__jp> writes

>As a result of the Great East Japan Earthquake on March 11, 2011,
>Japanese paper and book conservators are struggling with the rescue
>and recovery of paper-based objects that have been fully or
>partially soaked, or moistened with seawater. ...
>...
>A survey of published conservation literature has not provided any
>information regarding the recovery of such objects, including
>information related to the long or short-term effects on paper
>following exposure to the contents of seawater.

The first thought that comes to my mind is that sodium salts may act
as oxidants on paper--not really sodium chloride itself, but some
other compound already present in paper might that react with
sodium. The first thing one would do is to wash the pieces in order
to remove sodium. But you should check the presence of sodium after
the treatment, too. I guess some sort of tester should exist, in
paper strips form, or electrode device (such as pH tester).

It is also true that all the degradation reactions are encouraged by
moisture, so drying up the paper material should be the first
option. Freeze drying, or freeze and then air dry are valid options,
too (depending on which inks, adhesives, bindings you are dealing
with). I will investigate the effects of sodium in dry material, too
and I will let you know.

Barbara Cattaneo
paper conservator
National Library of Florence


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                  Conservation DistList Instance 25:4
                   Distributed: Monday, June 27, 2011
                        Message Id: cdl-25-4-007
                                  ***