Page 197 - Manual for Activities directed at the Underwater Cultural Heritage

loss of information. That is why it is necessary to properly preserve and stabilize the objects on site, or in the laboratory, before any further phy- sical intervention takes place.
It would be presump- tuous to try to present the state-of-the-art of conser- vation and restoration in a few lines but the major stages in post-excavation procedures and methods can be highlighted.
The overall conservation-restoration procedure proposed by conservation laboratories for treating underwater archaeological artefacts can be viewed in four key stages which follow each other chronologically:
o Preventive conservation and storage: begin as soon as the artefacts break the surface of the water. When the collection enters the conservation laboratory, it is usually stored preventively in the same tank that is used on site, in order to avoid another brutal change in the environment.
o Condition report and diagnosis: upon arrival at the conservation laboratory, every artefact must be precisely marked, identified and described in order to record it and its condition. The condition report, also containing a diagnosis, will ensure proper transmission from hand to hand in the conservation laboratory and allows conservators to decide if complementary diagnoses are necessary (material chemical analysis, radiography, tomography, endos- copy,...). The condition report and the com- plementary analyses will then allow con- servators to decide what kind of treatment will be the most relevant for the materials and the conservation state of the artefact.
© National Museum of Underwater Archaeology. ARQUA. Mechanical cleaning of a bronze figurine at the conservation laboratory of the ARQUA Museum, Cartagena, Spain.
Mechanical cleaning using micro-sandblaster, micro-chisel, and micro-scalpel is part of the curative conservation procedure that comprises several stages of cleaning of calcareous concretions, stabilisation and rinsing.These procedures help to render the object more comprehensible and allow later for risk-free restoration work.
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Conservation and site management