Lignin and paper permanence

In reply to Paula Destefano's posting on the distlist today, I'd
like to clarify the points to which she refers in my article in the
CPA Newsletter and try to respond to her question.  Some background
first:

The Canadian cooperative research project on the impact of lignin on
paper permanence is just about to wrap up.  When my article was
written, work had completed on the first phase--the study of the
impact of lignin on various papers which were submitted to
accelerated aging.  These results were about to be (and now have
been) reported by Paul Begin of the Canadian Conservation Institute
at the ARSAG conference in France in April.  It was appropriate that
specifics be first presented by the researchers themselves and also
not to preempt their presentation at ARSAG.  Since then, phase 2
has been completed and the scientists are writing up these results.
Phase 2 covers the study of these same papers but with an added
twist--the papers were subject to extreme exposure to pollutant
gases before being aged.  We are hoping that all the results will be
ready for distribution and dissemination and discussion in the next
few weeks.

As a result my use of the word "benign" was carefully chosen to
reflect first phase results.  Ms Destefano is right in that there
was no surprise in the results I reported.  (Although I was
surprised at how well alkaline lignin-containing papers did in the
degree of polymerization (DP) testing). What IS new is that both
physical and chemical tests were carried out first on a variety of
well-characterised control samples; second, on these same samples
once aged; and then, thirdly, on identical samples which were first
exposed to high pollution levels and then accelerated-aged.  It will
be the phase 2 results, compared to the control samples of phase 1,
which, I hope, will provide the information that librarians and
archivists and conservation scientists will be able to use to
determine the effect of lignin on permanence.

I regret that my use of the word "benign" was misleading, however,
until the results of the pollution work is available, we will not
know how lignin behaves in a polluted environment.  Is it stable if
buffered? Is it a catalyst for degradation?  I eagerly await the
answers to these questions.

Jan Michaels
Preservation Policy and Planning Officer
National Library of Canada

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                  Conservation DistList Instance 10:99
                    Distributed: Friday, May 9, 1997
                       Message Id: cdl-10-99-001
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