Page 196 - Manual for Activities directed at the Underwater Cultural Heritage

 © UNESCO. Amphora fragments, bones and other remains of the commercial harbour of Theodosius,Yenikapi- Istanbul, Tur key.
During the archaeological excavation undertaken in the harbour of Theodosius (5th - 10th century AD), 34 ships were excavated.While investigating the site of the ancient harbour
of Theodosius, archaeologists found Numerous debris objects, bones and small artefacts which had to be sorted, stored and identified with tags. A diligent documentation is essential, as it is key to preserving information on the location of artefacts on the site and for obtaining scientifically valid information.
© National Museum of Underwater Archaeology. ARQUA. Control of the process of lyophilization at the conservation laboratory of the ARQUA Museum, Cartagena, Spain.
Freeze-drying is a dehydration process used to preserve a perishable material. By freezing the material, then reducing the surrounding pressure and adding enough heat, it allows the frozen water in the material to sublime directly from the solid phase to the gas phase.
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water in the bottom of the tank must ensure 100% humidity during the transit.
Storing recovered objects
Immediately after the transit, artefacts must be re- immerged in a receptacle or a tank in an environment identical or as close as possible to that in which they were discovered. If this is not possible, then storage in a 100% humidity atmosphere is acceptable. The aim is to anticipate, restrict or halt any acceleration in the degradation of objects after their discovery and excavation. An appropriate storage must be en- visaged in the interest of long-term conservation: every storage action must be planned considering that the storage can last weeks, or even years. Moreover, the solutions adopted for individual ob- jects must be simple and easily renewable.
Each artefact should be wrapped in a specific material (conditioning material and conservation- grade inert material), which avoids shocks while favouring the rinsing procedure. All finds should be stored separately and according to constitutive material as each particular archaeological material is subject to specific degradation. The subsequent work led by the conservator will usually allow the original surface to be ‘revealed’.
After intervention
Every project manager must plan all actions to which
finds are exposed, from the initial handling in the excavation all the way through to the conservation laboratory in order to ensure an accurate traceability
for each artefact. Any loss of material constitutes a 195
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Conservation and site management