Crystallization associated with iron gall ink

I have been examining a watercolor and ink drawing on paper by Jean
Francois Millet in our collection and have noticed a white
crystalline formation on the surface of the drawing in the areas of
the heaviest ink application.  The majority of the ink lines have
bled, appear warm brown in tonality and have corroded the paper,
indicating that the ink is iron gall.

With the analytical laboratory here at our museum, we have carried
out X-ray Fluorescence analysis of several of these areas and have
detected only iron with trace amounts of lead.  (The lead present
does not seem of sufficient quantity to be responsible for the
crystals.)  We are considering sampling the drawing in order to
conduct Fourier Transform Infrared Spectroscopic analysis for
identification of the substance; however, prior to destructive
testing, I have been trying to find references in the vast
conservation literature to any similar phenomena associated with
iron gall ink.  Thus far I have been completely unsuccessful.  Is
anyone familiar with this crystal formation or have references that
may discuss similar observations? I would appreciate hearing any
experiences that others may have had in this regard.

Deborah Carton
Museum of Fine Arts
465 Huntington Avenue
Boston, MA 02115-5523


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                  Conservation DistList Instance 16:5
                   Distributed: Tuesday, July 9, 2002
                        Message Id: cdl-16-5-005
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