BINDING MEDIA IDENTIFICATION IN ART OBJECTS: THE STATE OF ART IN EUROPE. RESULTS OF THE INTERNATIONAL SURVEY

• A. K. Tsakalof, S. Sotiropoulou ("Ormylia" Art Diagnosis Center, Sacred Convent of Annunciation, 63071 Ormylia-Chalkidiki, Greece)
• I. Chryssoulakis ("Ormylia" Art Diagnosis Center, Sacred Convent of Annunciation, 63071 Ormylia-Chalkidiki, Greece and National Technical University of Athens, Department of Chemical Engineering, Iroon Polytechniou 9, 157 80 Zografou Campus, Athens, Greece)

The identification of binding media used in paintings for pigments dispersion and fixation gives valuable information, which contributes substantially to the conclusions about the painting techniques applied. As it can be anticipated, this information is important both for art historians and conservators. But, even today, the process of identification is not straightforward and different approaches have been developed in different laboratories.

In the framework of the EU Infrastructure Cooperation Network program "Laboratories on Science and Technology for the conservation of European Cultural Heritage" (Labs TECH) the review of techniques and strategies used for the characterization of binding media has been endeavored. The review comprises the experiences of the internationally distinguished European laboratories working in the field of scientific and technological applications to the study of cultural heritage and covers all the main steps of the analysis from sampling to the eventual treatment of the analytical results. The review is based on the questionnaire elaborated at the "Ormylia" Art Diagnosis Centre (Greece), which was disseminated between the participating laboratories. The questionnaire covered wide range of the details of the protein and lipid binding media analysis, including sampling, sample preparation, details of instrumental analysis, analytical data extracted from the analysis and ways of these data treatment. Except of the pure analytical aspects, the questions clarifying laboratory/group organization and profile were formulated (personnel, participation in EU projects and fundamental research, number of analysis per year and analysis price policy etc.). The laboratory profile information can be valuable for the development of interlaboratory cooperations in the field of binding media analysis in accordance with the main goals of Labs TECH program.

According to the survey results a number of chromatography-based techniques are currently applied to the binding media identification and namely GC, GC-MS, Py-GC-MS, DTMS, HPLC. These techniques differ in their detection limits and correspondingly in the amount of sample required for the analysis. They also demand different sample preparation procedures and vary in the final information volume provided, analysis time and price.

The survey results also revealed that even today the binding media analysis is not so much straightforward as soon as relatively small percentage of respondents claimed that they are entirely satisfied with the reliability of method applied.

The critical review of the above mentioned and other survey results will be presented, giving critical insight on the methods used for binding media identification The Labs TECH program details will be also presented as well as the profile of the main European Laboratories involved into the binding media analysis and participating in the program and the survey.