Reproduction of museum objects

Maria Esteva <patrimon [at] fundantorchas__retina__ar> writes

>I would like to know if any conservator has experience or has dealt
>with the procedures for reproduction of ceramic, stone and metal
>objects from an archeological and ethnographic collection.

We have recently replicated (to an accuracy of one tenth of a
millimetre) an Egyptian limestone relief and two Roman marble
reliefs using non-contact replication methods. The reliefs were
scanned using a hand-held portable laser scanner, to obtain a
three-dimensional map of the surface, and the information obtained
used to control a precision cutting machine. The copies were cut
directly into stone. In this way it was possible to produce a
faithful copy of the surface (including the effects of weathering
and deterioration down to the last crack!) in the same material,
rather than a carver's interpretation of what the original surface
would have looked like. The Roman reliefs mentioned here were on
display on the outside of a garden temple in North West England and
had become so badly polluted and decayed that if they hadn't been
removed would have soon been lost for ever. The originals have been
cleaned (by laser) and conserved and will now be displayed indoors
while the replicas will be placed back on the outside of the temple.
This technology has developed so far over the last ten years that
the resolution of replication can virtually be tailored to the job -
the higher the resolution though, the longer the machining time and
the higher the cost! Each of these reliefs has probably cost us
somewhere in the region of a few thousand pounds to produce.

We have also recently made replicas of a plaster model (for a bronze
sculpture, approximately 50cm tall) for the owner while the original
is on long-term loan at a museum. This involved scanning the object
by laser and then building up a copy by a process known as Laminated
Object Manufacture. This process builds a model, layer-by-layer,
using paper. Once the model has been produced a mold can be created
and a copy of the original created in plaster (or whatever material
is chosen). Again, resolution is determined by the money available!
Once the replicas have been made they require the addition of
'patina', colour etc by a skilled conservator. Larger objects can
also be produced by these methods by dividing the artwork (not
physically!) into smaller more manageable parts.

Non-contact replication methods such as these have great potential,
especially for the production of high quality replicas of extremely
fragile artworks. This technology also has implications in faking
and it is therefore important that museums are aware of what is
already possible!

Martin Cooper
Laser Technology
National Museums and Galleries on Merseyside
Conservation Centre
Whitechapel
Liverpool L1 6HZ
+44 151-478 4904
Fax: +44 151-478 4990

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                  Conservation DistList Instance 12:27
               Distributed: Wednesday, September 16, 1998
                       Message Id: cdl-12-27-003
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