MICROSCOPY, MICRO-CHEMISTRY AND FTIR AS ANALYTICAL TOOLS FOR IDENTIFYING TRANSPARENT FINISHES CASE STUDIES FROM ASTRA MUSEUM – SIBIU

Abstract

Conservation of cultural heritage relies on scientific investigation of artefacts, a key point being identification of the original materials. In this context, besides wood species identification, investigation of finishing layers is of ultimate importance for old furniture and any other wooden objects with historic, documentary or artistic value. The present paper refers to a series of micro-destructive investigation methods applied for identification of finishing materials, namely: simple in situ and laboratory physical tests, optical microscopy, micro-chemistry and FTIR – ATR analysis. Small samples of finishing layers were taken from four furniture objects belonging to CNM ASTRA Sibiu and were analysed according to the usual procedures of the laboratories from Sibiu and Brasov. The results showed that physical tests and microscopy are useful to get basic information on the samples’ morphology and possible classes of coating materials, while micro-chemistry revealed by some successive tests more specific information on the type of finishing materials. FTIR - ATR is a rapid method of identifying the coating materials based on available reference samples or spectra. However, this is not always straightforward and preliminary physical tests of solubility are useful to select the adequate references, while micro-chemistry tests could complete the FTIR result, especially for those components of the finishing layer present in very small amounts (less than 5%), bellow the FTIR sensitivity. Corroboration of microscopy, physical and micro-chemistry tests with FTIR can provide more reliable results in terms of finishes identification and also valuable information for restoration.

Keywords

• furniture
• conservation
• investigation
• finishing layer
• microscopy
• micro-chemistry
• FTIR