Features-of-interest on art objects : re-location and micromanipulation for multiple-instrument analyses

Advanced microanalytical techniques are extensively used in art and archeology for validation and authentication, studying materials and processes, attribution, obtaining forensic clues, and more. Multipleinstrument analyses of selected features-of-interest (FOIs) on an object are required to provide their comprehensive characterization. It is necessary, therefore, to be able to repeatedly locate and re-locate the very same FOI on an object in different instruments, often in remote laboratories. For example, a FOI may be a tiny ink stain on a papyrus, paint on a ceramic tile fragment, or corrosion spots on an ancient coin. A precise re-location method, sometimes down to the micrometric range, should be utilized. The first examination of an art object is usually done under a light microscope, a SEM equipped with a microanalyzer for elemental composition determination, or a micro-XRF scanning device. They are termed "source instruments". Then, the object is transferred to a "target instrument" where the same FOI is re-located and subjected to further analyses. A target instrument may be the synchrotron (for micro-XRF tomography, micro-XRD, micro-XANES, etc), micro-Raman, LA-ICPMS, SIMS, or even a micromanipulation system where microscopic evidence can be removed leaving the rest of the sample practically intact. The described methods have been originally developed for single radioactive particles analyses, and implemented in several laboratories in the fields of environmental research and nuclear forensics. In this paper the FOI re-location and micromanipulation methods will be discussed, and their application in a test case. In the test, a parchment sample, with an inscription on it as well as a few planted small agglomerates of metallic particles, was transferred between 3 remote laboratories. The same FOIs were re-located and measured by different analytical techniques. This experiment demonstrates the applicability and potential value of the methods to art and archeological objects. INTRODUCTION A small number of intact or nearly intact scrolls and about 15,000 fragments were recovered in the '50s from caves in the cliffs of the Dead Sea west shore. The famous Dead Sea Scrolls (DSS) collection has been studied extensively by scholars for 60 years. Recently natural scientists started an ambitious international project of the material study of the scrolls [Rabin, 2007a]. With the help of non-destructive analysis methods they are addressing two central questions of the Dead Sea Scrolls research: their long term preservation on one hand and their provenance, on the other. The aim of the project is characterization of the writing media (parchment and inks) of the ancient scrolls found in the Dead Sea area. The information obtained will be implemented into conservational, historical and palaeographic research. To achieve a comprehensive characterization and meaningful results specialists from different laboratories united their efforts. Thus, the objects under study are moved from place to place for experiments. Usual 9th International Conference on NDT of Art, Jerusalem Israel, 25-30 May 2008 For more papers of this publication click: www.ndt.net/search/docs.php3?MainSource=65