Chromatographic techniques as well as infrared spectroscopy are preferentially used to identify all types of organic materials. These methods enable the analysis of paint media and varnishes on paintings and sculptures, historical lacquers on artistically designed surfaces and furniture, organic products from the field of archaeology as well as everyday conservation products such as solvents, cleaners and other agents used in conservation.
The media in old paint layers and lacquers is analysed using a special procedure involving multi-stage dissolution of the samples and subsequent identification of the components by means of gas chromatography, mass spectrometry and amino acid analysis. In this manner, it is possible to identify oils, natural resins, waxes, proteins (e.g. egg yolk, egg white, glue or casein) as well as gums (vegetable glues). In favourable cases, in addition to conclusions about the type of paint medium, it is also possible to specify the quantitative proportions as well as the state of ageing.
