Stručni rad
Restoration-Conservation Works on a Late Roman Mosaic in the Chapel of St. John in the Monastery of St. Francis at Pula
Andrea Sardoz
; Arheološki muzej Istre, Pula, Croatia
Toni Šaina
; Odjel za zidno slikarstvo i mozaik, Hrvatski restauratorski zavod Užarska 26, 51 000 Rijeka, HR
Sažetak
In May of 2009 a field inspection and examination of
the mosaic in the monastery of St. Francis at Pula was
organized, which led to the conclusion that it was in a
critical state, whereupon restorers from the Archaeological
Museum of Istria and the Croatian Conservation Institute
started with their restoration/conservation activities. A
large portion of the damages ensued as a consequence of
humidity that extended itself in a broad belt alongside the
northern and western edges of the basin where it was also
held up. Preliminary analyses showed a presence of salt.
After the removal of dust, crystallized salts and crumbled
mortar from the large central section, it became apparent
that the nucleus degraded quite a bit. By observing the
old borders we concluded that the nucleus layer crumbled
and hence degraded by almost a whole centimeter. After
the drawn documentation in 1:1 scale was finished, the
dust and crystallized salts from the surface as well as
the crumbled mortar were removed. A photogrametric
survey was performed as well as scanning with a 3D
scanner. Afterwards, work began on the removal of old
restoration borders that were replaced with lime mortar.
The nucleus of the mosaic was well swept and vacuum
cleaned, and was thereupon consolidated with a 5%
solution of Paraloid B72 in acetone. The severed, lifted
and strewn tesserae were then returned to their original
position with the help of pincers and cutters. Thus treated
sections of the mosaic were then glued from underneath
using Vinavil 59 glue and gauze. In 2009 there were no
plans to lift the mosaic, and so after the most urgent
preventive interventions were performed, it was covered
with a layer of cellulose pulp. The pulp should lessen the
deleterious effects of salt, and this could be achieved by
continuously changing the watery cellulose pulp over
a longer period of time, until the analyses of the pulp
showed a satisfactory result, i.e. that there are no soluble
salts on the mosaic. In this manner it would be possible
to get rid of the deleterious salts on a permanent basis.
It is important to mention, however, that the elevation
of the surface of the mosaic is inferior to the elevation
of the external surrounding ground, which represents
an additional problem when combating humidity. In
order to prevent a further destruction of the mosaic,
the prime task should be to stop humidity (water) from
penetrating the substrate of the mosaic. It is, therefore,
necessary to remove all sources of humidity, which affect
the mosaic. Every restorer and/or conservator-restorer is,
hence, obliged to deal with this matter in a scrupulous
way over a prolonged period of time.
Ključne riječi
mosaic; tessera; nucleus; border; conservationrestoration; salt analysis
Hrčak ID:
63744
URI
Datum izdavanja:
19.11.2010.
Posjeta: 3.145 *