Plasticine as art medium

The library has received a donation of several 3-D pictures made of
plasticine, not polymer clay, that were used as models for
illustrations in children's books. These pictures are to be hung in
the children's sections of the branch libraries. As we are all paper
conservators, we are not sure about the best method of framing them.
The artist has framed previous works in sealed acrylic boxes;
however, one earlier piece in the library's collection now has tiny
flakes of blue and green in the bottom of the box.

Is this flaking what one might expect plasticine to do as it ages?
Is there anyway to prevent it from occurring? Could the acrylic box
or the fact that it is sealed be a factor? Would a  shadow box of
urethaned wood lined with archival mat board be a better idea? The
information on plasticine used as an art medium for long term
retention seems to be limited.  I would appreciate any information
that would be available on this subject. Thank you,

Ann Douglas
Conservator
Preservation and Digitization
Toronto Reference Library
789 Yonge Street
Toronto, ON M4W 2G8
416-393-7127
Fax. 416-393-7147


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                  Conservation DistList Instance 18:13
                 Distributed: Tuesday, August 17, 2004
                       Message Id: cdl-18-13-018
                                  ***