Spectroscopic analysis (SEM-EDX and/or Raman) of liquids, powders or solids.

Embedded paint fragments will be analyzed using SEM-EDX and/or Raman microscopy. The aim of the conducted analyses is to distinguish and identify all present paint layers and used pigments and provide valuable information on the painting techniques or possible pigment degradation. Paint fragments are embedded typically in acrylic/epoxy resin and cross-sectioned, these are subsequently polished and prepared for SEM-EDX analysis by carbon coating. The cross-sections are examined by SEM-EDX. Using backscattered electron imaging (BEI) it is possible to visualize the paint fragment with a contrast based on local mass density. Therefore, heavier pigment grains, e.g. lead white, will have a higher grey value compared to organic binder material. Energy dispersive X-ray analysis allows us to obtain the very local chemical composition which can be used to identify present pigment grains. In combination with the scanning character of SEM it is possible to create elemental distribution maps of the embedded paint fragments. Raman microscopy can be applied as complementary technique. In addition to the elemental composition determined by SEM-EDX it is possible to obtain the chemical speciation of present pigment grains on a comparable microscopical scale. Not only can this be done by a point-by-point analysis but is also possible to create two-dimensional distribution maps of the paint cross-section.

Keywords:ELECTRON MICROSCOPY (SCANNING), RAMAN SPECTROSCOPY, SPECTROSCOPY, CULTURAL HERITAGE

Disciplines:Spectroscopic methods

Project type:Service project