Janez Kosel

 

 

Short bio Institute for the Protection of Cultural Heritage of Slovenia, Conservation Centre, Research Institute, Ljubljana, Slovenia janez.kosel@zvkds.si Janez Kosel has a PhD in Biotechnology and is a Conservator-Restorer at the Institute for the Protection of Cultural Heritage of Slovenia. He has expertise in immunology, genetics, metabolomics and microbiology. He currently is the leader of two Slovenian national research projects, which employ metagenomics for the identification of microorganisms on cultural heritage (ARRS, BI-RS/20-21-013), and aptamers/antibodies for the identification of proteins in archaeological ceramics (ARRS, J7-3147).

 

ABSTRACT

Fluorescent and confocal laser scanning microscopes for the analysis of cultural heritage items: (1) organic binder identification (2) and microbiological analysis

Firstly (1) we addressed the problematics of proteinous binder characterisation within a cross-section of a painting, using immunofluorescence microscopy (IFM). Problems arise from certain pigments, which can alter the epitope sites of target binders (lead white) or can exhibit a strong natural autofluorescence (lake pigments). This problem was addressed by preparing two-layered model samples which contained a lower egg tempera paint film and an upper oil paint film, and both films were made of the same pigment. To reduce unspecific fluorescence (UF), apart from widefield fluorescence illumination, laser-scanning confocal IFM (Axio Imager.Z2m LSM800 microscope; Carl Zeiss, Slovenia) was performed. Within the same laser-scanning system, 3D surface topography models were constructed, which were used to check off any UF originating from cracks or holes.

Secondly (2), widefield fluorescence microscopy was used to precisely quantify the initial surface growth stages of 11 fungal strains, isolated mostly from cultural heritage institutions’ interiors, on egg tempera paint films. The susceptibility of different pigments to mould development was tested at three different relative humidity (RH) levels of 55%, 63% and 74%. Egg tempera paints were applied on glass and wooden supports, which enabled us to examine the effects of hygroscopic materials (wood) on mould growth. This was the first systematic evaluation of mould growth on painted support materials at specifically low RH levels.