Proceedings e report - Firenze University Press

WOOD SCIENCE FOR CONSERVATION OF CULTURAL HERITAGE
volume, with a hollow space in the centre. This can be seen in a X-ray image (Fig. 6). In addition to
these large scale wood pieces, smaller and more irregular cedar pieces were put to fill spaces, gaps and
edges, especially in the Jesus’ head. With the X-ray we could also identify two different kinds of nails,
some large hand-made nails, used inside the structure to build up the sculpture, and other smaller
industrial-like nails, used in a recent intervention, over the paint layer, to prevent the detachment of
the multiple wood pieces.
Fig. 5 – Nossa Senhora do Rosário. Base of the sculpture and correspondent cut sections of the two different
species: (Y) Khaya sp. (mahagony) and (X) Cedrus sp. (cedar); (C) wood wedge. The lines show the distribution
of the joint lines.
Fig. 6 – Nossa Senhora do Rosário. Left: detail photography of the sculpture’s waist; Right: X-Ray of the same
detail. (X) board of cedar; (C) wood wedge, (P1) handmade nails, (P2) industrial nails.
Several experimental studies of the physical behaviour of the wood and the ground layer were made,
based on the original construction techniques 2 . We wanted to understand if the combination of a
coniferous (cedar) with a deciduous (mahogany) wood, and the interaction between the wood and the
ground layer materials, might have influenced the sculptures’ conservation condition, leading to its
actual critical state of conservation. By gathering records of the different reactions of wood to various
climatic conditions of temperature (T) and relative humidity (RH) our studies confirmed that
hypothesis [7].
2 During the year 2007 Diogo Sanchez completed his studies of conservation and restoration at the Universidade
Nova de Lisboa, Faculdade de Ciências e Tecnologia, Lisboa, comparing Nossa Senhora do Rosário’s wood
behavior and its effects on the ground layers, first with diagnosis and later with experimental work with the same
kind of materials. The physical behavior of the ground layer materials and its interaction with the wooden
support was evaluated. Physical parameters as hardness, break force, flexibility and color alteration were
analyzed as well the different reactions of the wood to various climatic conditions of temperature and relative
humidity. The conservation work on the Nossa Senhora do Rosário is still being done.
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