In 2002 the annual conservation workshop started with the
treatment of the retable of "The Annunciation". The retable is a nice
altarpiece which is comparable as a somehow typical example for style and
craftsmen's tradition for the time period and area.
The retable though appeared in fairly bad condition upon first
investigation The painting, wooden constructions and the polychromy of the
architectural structure are degraded due to insect infestation, nestling bats
and severe climatically stress. Parts of the ornaments and of the paint layers
are falling off the surfaces.
A first approach to conservation treatment was carried out in
summer 2002. Directed by the governmental office of monument care Dubrovnik the
wooden inventory of the church Maria Sunj was fumigated with methyl bromide gas
to kill the wood eating insects. This treatment was very important, because
further conservation steps can only be successful by eliminating general
damaging influences.
The retable consists of the polychrome wooden architecture and a
central canvas painting depicting "The Annunciation". The retable architecture
is shaped as a portico.
The altarpiece is located in the southern transept of the church
Maria Sunj. On the hidden bottom-side of the left console of the architrave a
signature points to the date of origin: the 20th of March 1637.
The retable rests on the altars' mensa and two wooden pedestals
forming a continuation of the outlines on the sides of the whole altar.
The altar
The altar rises on a two stairs podium. The stipes is made of
rough hewn limestone forming masonry.
The mensa consists of three plates of limestone with a thickness
of nearly 10 cm. The antlered stone was set in the middle plate. The retable
rests on the altars' mensa exceeding the total width of the mensa on both sides
to approximately 50 cm.
The single architectural elements are simply placed on top of
each other and fixed with metal rods to the wall.
In present state the wooden structure and the painting are placed
to the wall touching the plaster coat.
Technical description - Construction
The whole structure of the retable was constructed in a uniform
way. Wooden beams, boards and mouldings shape the framework and were jointed by
hand forged iron nails. Classical wood joints are missing as well as glued
connections. Even the carved ornamental applications are fixed with nails on
the flat surfaces of the construction.
Wood species
Beams, boards and mouldings, the functional parts of the
structure are made of fir wood. The sculptural parts of the half-columns and
the ornamental applications are made of light, dense poplar wood (Populus
spec.) which serves well for carving. Concerning the mouldings, the profiled
ones are made of coniferous wood. Solely the above cornices and the carved
mouldings with egg and dart-patterns are made of poplar wood.
Polychromy and gilding - Summarizing the actual
results
The polychrome design was carried out in a rather distinctive
way. Following a first layer coating with glue based water two to four
grounding layers made of gypsum and animal glue were applied. The gilded parts
were subsequently grounded with an extremely thin layer of ochre-colored
poliment.
After gilding the ornaments and mouldings, the background was
painted in two steps with two variations of blue paint. The bottom layer is
coarse-grained, with big glass-like pigments. The upper layer has a finer
structure.
The entire polychromy was executed before mounting the retable.
Once in upright position surpluses of paint started running on the surface
forming drops of paint.
The structure seemingly was painted in a very fast and free
manner. This obvious on the parts where carved ornaments of the retable were
lost before gilding and simply weren't replaced. The shape of the missing
ornament was faked by gilding the flat surface of the underlying construction.
State of condition before treatment - General
observations/Causes of damage
The retable suffered under various influences. Climate condition
and the assembly of the retable, insect infestation plus the crash to the floor
of the architrave including the gable parts during an earthquake in 1996, are
the main reasons of the present poor condition.
Construction/Fixation to the wall
The construction of each single part of the retable seems to be
stable. Hand forged iron nails join the wooden parts. The pedestals form an
exception. Some of the connections are not stable and therefore movable to a
certain extent.
Metal corrosion
The hand forged iron nails and the rods are corroded because of
humidity and oxygen. The metal rods surfaces show typical rust phenomena.
Considering their usage since the early 17th century their state of condition
is rather satisfying. However some of the corrosion products affected the
wooden structure and the paint-layer, coloring the surface and damaging the
textures of the wood.
Assembly and position of the retable
The whole weight of the altar's construction rests on the
predella which exceeds the mensa to both sides. The two pedestals once were
meant to support the predella. At present the left zone of the predella hovers
above the left pedestal. A wedge was inserted to bridge the gap.
The entire altarpiece is slightly leaning to the right .
Wood Insect damage
All static elements - boards and beams are made of coniferous
wood and infested by wood eating insects to a more or less minor extent.
Concluding investigations showed no serious dangers to the static function of
the architectural elements. Few decayed surface areas nevertheless need wood
stabilization.
Ornaments and mouldings as well as parts of the pillars made of
poplar wood are also made of poplar wood and show infestisations to a much
greater extend. Insects of the Anobiidae family (- probably Anobium punctatum
-) destroyed the wood structure to approx. 40% of the original substance in
several areas. A number of ornaments and mouldings are completely lost.
