Salted paper print

I am looking for advice regarding a salted paper print that has been
marked with an indelible ink marker.  The print's colour is a rich
purple-brown with very little fading evident except around the
edges.  There does not appear to be a surface coating of any kind.
The image and paper support are in very good condition.  The
photograph has been marked with a Staedtler Lumocolor Permanent
superfine "S" blue ink pen (product number 318).  The mark measures
0.8 cm in length and falls in a medium-light density area. The mark
is readily visible.

We have carried out some initial tests on a homemade salted paper
print in a medium density area whose substrate is coarser and much
thicker than the damaged photograph.  It's difficult to tell how the
original will respond as it quite different from the test sample. We
tried an acetone/Fuller's Earth poultice with a mylar mask and the
ink responded to a limited degree.  We had greater success lifting
the ink in the centre of the line than at the edges where the ink
was slightly heavier.  We then tried alternating between a Fuller's
Earth/acetone poultice from the recto and acetone applied with a
fine brush to the verso on a suction table.  I was able to draw much
of the ink from the substrate without any visible change to the
silver image however I was unable to remove all traces of the ink.
We then tried using an acetone/cellulose poultice with mylar mask
and the ink was slower to respond.  It has also been suggested that
we try a poultice using toluene:xylene:acetone or ethanol (3:3:1),
though we haven't carried out this test to date.  Further, there has
also been a  suggestion that we might try light bleaching to for the
residual ink.

Before we attempt any solvent treatment or light bleaching we were
wondering if anyone could provide more information about any other
types of poultices that might be suitable in this situation?  Are we
treading on dangerous ground even considering doing a solvent
treatment?  What other alternatives might we consider?  Any advice
would be gratefully appreciated.

Andrea Reichert
Getty Intern in Paper Conservation
Centre Canadien d'Architecture
1920, rue Baille
Montreal, Quebec H3H 2S6, Canada
514-939-7000,  ext. 1204
Fax: 514-939-7020


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                  Conservation DistList Instance 15:63
                  Distributed: Tuesday, March 19, 2002
                       Message Id: cdl-15-63-021
                                  ***