The feasibility of using portable X-Ray radiography for the examination of the technology and the condition of a metals collection housed in the Museum of Ancient Messene, Greece

Abstract

Most museums in Greece with metals collections cannot undertake the necessary examination of their objects by X Ray Radiography, because there are limited funds to purchase such an in-house system, and the laws for the management of cultural heritage in Greece does not allow for removal of museum objects for such analyses without permit, which is often difficult to obtain. Under the initiative of the European 6th Framework funded project PROMET, the TEI of Athens set up a portable X-Ray Radiographic unit to examine the collection of iron and copper alloy objects from the Museum of Ancient Messene in Greece in-situ.  The collection includes different types of artifacts from copper and iron alloys (weapons, toolsinstruments, accessories of doors and furniture, decorative artifacts, vessels, figurines-statuettes). Around 1000 objects were examined using the portable X-Ray radiographic system, in order to distinguish the characteristic technological features and to survey the condition of the artifacts. The paper describes the feasibility of using such a portable system to examine large archaeological collections of metal objects, which is considered a necessary first-step before undertaking conservation treatment. Furthermore, the interesting features and condition of the museum metal artifacts in Ancient Messene are described. For example, the iron artifacts exhibit clear signs of active corrosion, but it is not always easy to determine the exact amount of remaining metal or the initial shape and form of the artifact. Artifacts made by copper alloys - were either cast or hammered or both, but sometimes it was difficult to distinguish these two manufacturing techniques by visual inspection alone, especially for thin and small objects. Also, some of the artifacts exhibit surface decoration and features, not always visible, due to the presence of thick corrosion layers. An interesting example was the case of a copper alloy shield from the end of 4thbeginnining of 3rd c. B.C., where the X-ray radiographic system identified a decorative-motif and epigraphy on the surface, which was not clearly visible prior to the examination with the system. The first step included the purchase of a used Military Tubestand X-Ray Apparatus, MobilePortable, manufactured by Picker X-Ray Corp. The portable X-Ray Radiography unit was purchased for a small cost, around 1.700 Euros. The system was transferred by car to the museum of Ancient Messene for analyses of the objects. The results in terms of determining the amount of metal remaining and impression of details of the objects were very good, but a problem was the long working time when the films had to be developed at a local hospital with the necessary facilities. Thus, it was considered necessary to make the radiography system more feasible for use in-situ, by also developing the films in-situ, which involved the purchas  of a portable film processor Curix 60 manufactured by Agfa. The system exhibits the following advantages: top quality, low operating costs, simplicity of use, and ease of servicing and environmental protection. The film processo  cost around 4.700 Euros. Examining over 1000 objects of different shapes and dimensions in two days required operating the system 8 hours each day. For the examination of these objects, 85 radiographic films (dimensions 24X30 and 35X35), 8 bottles of developer liquid and 5 bottles of fixer liquid were used. The total cost of the supplies was around 400 Euros. The portable radiography system worked well in examining all the metal objects from Ancient Messene, because it could be applied easily in-situ in the storage room of the museum. The films could also be easily developed with the portable film processor in the bathroom near the storage room. The examination was considered essential so that the conservator(s) can make the necessary decisions on how to clean and/or stabilize the metal artifacts.