Roman wall paintings

The Archeologisch Diensten Centrum (ADC, Archaeological Service
Centre) carries out archaeological excavations (large
infrastructural as well as small-scale) in the Netherlands.

In the south of the Netherlands, we have been excavating a Roman
villa. You are invited to take a look at
<URL:http://www.romeinsevilla.nl> (in Dutch but with lots of
photographs that speak for themselves). There, we have found
halffabricate columns, a Roman iron window and... wallpaintings
mostly in the frigidarium bath building. Over 50  crates of
material, two mortar types and beautiful colours. No figures yet,
but lots of plant ornaments. The fragments are being cleaned
carefully by three university students with water, dentist
instruments, soft brushes and cotton swabs. I am supervising the
cleaning work. The next step would be consolidating the fragments
since they are very brittle. Mostly, the colours and the mortar
withstand the cleaning activities but the fragments remain very
soft. Our wallpainting-expert wants to puzzle and figure out the
structure and patterns but that is only possible when the fragments
are stable.

Advised by a conservator from Maastricht, we used a water soluble
acrylic dispersion, Primal, on site on some of the most brittle
fragments (20%). We would want to use it for consolidation, too
(10%) either by spraying or by submerging the fragments. But I am
not sure. I have heard that Primal would be similar to Rhodopas,
something you wouldn't want to use on wall paintings. Other methods
that were suggested to me:

    *   Paraloid B72? in dichlorethylene, a method which apparently
        is also in use in France (Centre d'Etude des Pentures
        Murales Romaines)

    *   white wood glue (10%) in water,  a method used in the past,
        which creates a firm outer layer but is not very good
        reversible

My questions are: would anyone have suggestions for me how to deal
with our wall paintings? Ideas for treatment, storage or useful
literature references, own experiences? Does anyone have experience
with Primal or know about its effects? Or with Rhodopas?

Drs. K.A.N. Abelskamp
Coordinator Conservation
Coordinator Arbo
Archeologisch Diensten Centrum (ADC)
Energieweg 14
Postbus 112
3751 LT
3750 GC Bunschoten
The Netherlands
+31 033 2998181
Fax:+31  033 2998180


                                  ***
                  Conservation DistList Instance 16:23
               Distributed: Wednesday, September 25, 2002
                       Message Id: cdl-16-23-019
                                  ***