In-Reply-To: The letter of Thursday, 23 June 1994 10:51pm CT
 
I would like to add some clarification to Sharon Niscak's note about accession
number marking.
 
1. PVA sometimes stands for poly(vinyl) alcohol, but the PVA more often used
in museums for numbering (at least in the anthropology/archaeology collections
I'm familiar with is poly(vinyl) acetate.  It comes as small beads, or
sometimes already dissolved in a solvent, and is painted on the object.  The
number is then written on and then a top coat is added to protect from
abrasion. There are many kinds of poly(vinyl) acetates (both brands and
molecular weights). Some are very soft and sticky at room temperature, some
are very hard and brittle. Their qualities can also be affected by the solven
that is used to dissolve them.  Poly(vinyl) acetate also comes in an emulsion
form (Elmer's glue is a type of poly(vinyl) acetate emulsion). These emulsions
are generally considered unstable and unsuitable for direct contact with
museum objects.  Some poly(vinyl) acetate resins have been tested for
stability in conservation.
 
2. "B72" stands for Acryloid B-72.  Acryloid B-72 is an acrylic resin.  It has
been tested in conservation and is considered one of the most stable options
available.  It often comes as beads and has to be dissolved in a solvent.  Any
use of solvents in a non-laboratory setting brings up questions of safety and
toxicity.
 
3.Clear nail polish has been used in museums.  But it is inappropriate for
numbering objects because it is a type of polymer (cellulose nitrate for those
who care) that is notoriously unstable and will shrink, and yellow and peel
away from the surface taking your number and sometimes part of your object
with it.
 
I applaud the registrar's group for attempting to collect information about
numbering.  I hope they will post their ideas/findings/standards to the list.
 
Here are a few references that will help in your search for information:
 
Horie, C.V. 1987 Materials for Conservation, Butterworths: New York
(this has information on most of the polymers museum people have tried using
for all sorts of reasons)
 
"Use of Acryloid B-72 Lacquer for Labeling Museum Objects", Conserv O Gram
1/4, July 1993, National Park Service (this can be obtained through the
Government Printing Office (fax 202-512-2233).
 
"Labeling Museum Specimens" by Sara J. Wolf and P. Lynn Denton, Conservation
Notes, No. 11, January 1985. (this can be obtained from the Publications
Division, Texas Memorial Museum, The University of Texas at Austin, 2400
Trinity, Austin, TX 78705 (tel 512-471-1604))
 
I'd also suggest you talk to conservators in museums in your area.  Many of
them will have dealt with the numbering question for their own museums and
will be able to give other ideas and tips.  You can find conservators in your
area through the FAIC (Foundation of the American Institute for Conservation
of Historic and Artistic Works) Conservation Services Referral System.  They
will give you a free listing of conservators that can help.
 
Good luck.
 
Jessie Johnson
Assistant Conservator
Texas Memorial Museum
Materials Conservator Lab
University of Texas at Austin
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