Identifying writing implement

I am interested in learning the identity of a mark making implement
that was used to write the date "1840" on the label inside a violin
made by a noted 19th century French maker.  The date's medium is
blue and under magnification is clearly seen to sit on top of the
paper fibers rather than within them as would be the case with fluid
ink.  Also under magnification this medium has the sheen
characteristics of graphite (blue pencil?) or, anachronistically,
ball pen ink.  Interestingly, the lines are striated: it can be seen
with high magnification that the lines are actually composed of
seven closely spaced, parallel lines.  The striations do not
correspond to the paper fibers and must have been caused by the
writing implement. Any suggestions as to the implement used may aid
in the identification of authenticity or deception of this date.

Robert Lodge
Mckay Lodge Fine Arts Conservation Laboratory, Inc.


                                  ***
                  Conservation DistList Instance 19:44
                 Distributed: Thursday, March 16, 2006
                       Message Id: cdl-19-44-012
                                  ***