Home Conservation projects Conservation-Restoration Work on Small Finds from the Murter, Bisaga-Kornati Sites
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Conservation-Restoration Work on Small Finds from the Murter, Bisaga-Kornati Sites

Research of sites in the waters off the island of Bisaga in the Kornati archipelago has yielded an abundance of archaeological material, ceramic plates, jugs, porcelain cups, fragments of glass bottles and metal ware. Over forty different types of smoking pipe and carved wooden stems were found. Upon extraction from the sea the recovered archaeological material was brought in for conservation-restoration treatment.
In the first phase of the conservation-restoration procedure the desalination process was used to leech harmful salts, chlorides in particular, from the artefacts. The desalination process was initiated immediately upon receipt of the artefacts and was conducted by isolating artefacts in nets with their corresponding signatures appended and submerging them in a bath of tap water. The quantity of total leeched salts from the artefacts was monitored by taking regular measurements of the conductivity of the water in the bath and by determining the concentration of chloride present. An increase in conductivity signalled that salts had been leeched from the artefacts, while the precise concentration of chlorides was determined using a potentiometric titration instrument.

 

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Figure 1. Diagram of the change / drop in the concentration of chlorides with successive water changes in the desalination process

 

The water in the vats was changed when the concentration of leeched chlorides achieved a constant maximum – with every new change of water the maximum concentration dropped. The last several changes of water were done with distilled water to enhance the desalination effect. Upon the completion of desalination the artefacts were dried and examined under magnification in order to determine the state of conservation and the further course of conservation-restoration work.

 

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Figures 2a and 2b. Part of a metal artefact prior to conservation-restoration work

 

The metal artefacts received were in a relatively good state of conservation, with their surfaces largely covered with various corrosion products, encrusted mollusc shells, lime and organic sedimentary deposits. The porcelain and glass artefacts are partially fragmented and their surfaces largely covered with various calcification sedimentary deposits.

 

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Figures 3a, 3b and 3c. Parts of porcelain and glass artefacts prior to conservation-restoration work

 

A small number of ceramic smoking pipes were received in fragmented condition and damaged by the action of marine organisms, while the majority of the ceramic smoking pipes were in a very good state of conservation with visible calcification and lime sedimentary deposits on their surfaces.

 

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Figures 4a, 4b, 4c and 4d. Several different types of ceramic smoking pipe prior to conservation-restoration work

 

The cleaning of the ceramic smoking pipes was conducted by the combined use of scalpels of various dimensions, pins and chisels. Stubborn lime deposits that could not be removed mechanically were cleaned chemically with a mildly acidic aqueous solution – upon the completion of the cleaning process any excess solution was eliminated by rinsing in large quantities of distilled water. Following cleaning and the removal of surface deposits the ceramic smoking pipes were consolidated by submersion in a 3% aqueous solution of acrylic consolidant.

 

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Figures 5a, 5b, 5c and 5d. Several different types of ceramic smoking pipe following conservation-restoration work

 

Stubborn deposits were removed from the surfaces of porcelain artefacts using scalpels of various sizes. Work was conducted under magnification and exercising great care in order not to damage the original porcelain surface of the artefact that, upon cleaning, revealed various drawings and stamps. The glass artefacts were cleaned in a mild detergent solution. As a result of the good state of conservation of the glass and porcelain artefacts they did not require consolidation.

 

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Figures 6a 6b and 6c. Parts of porcelain and glass artefacts following conservation-restoration work

 

Metal finds were subjected to controlled mechanical cleaning under microscopic magnification up to the point at which the original surface was revealed, which on all of the artefacts was partially damaged. Scalpels and brushes of various profiles and sizes, micro abrasive blasting and an electric micro motor were used. A mixture of reversible Paraloid B72 polymer and Cosmoloid H80 microcrystalline wax in toluene was applied to the surfaces of metal artefacts as a final protection

 

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Figures 7a and 7b. Parts of metal artefacts following conservation-restoration work

 

Technical documentation was drawn up for each individual artefact following conservation-restoration work recording and describing all phases of work and all materials used.

 

Antonija Jozić