National Technical Museum

The identification of the composition of the paint layers (binders, additives, and pigments) is essential for the work of conservators and can also be used in many cases to determine the date of creation of works of modern art. Spectroscopic methods, specifically FTIR and Raman spectroscopy, are most commonly used to analyse modern pigments. These two methods complement each other and together provide a comprehensive view of the composition of the paint layer. The abilities of both spectroscopic techniques to identify pigments in the paint layer were investigated on a set of 24 model samples of pigment, the white, and binder mixtures and then verified by an analysis of a real sample.

První zmínka o pivovarství v královském městě Nymburce je obsažena v listině krále Jana Lucemburského z roku 1327. Mílové právo, které městu umožňovalo monopol ve výrobě piva v regionu, omezila až takzvaná Svatováclavská smlouva z roku 1517. Konec hegemonie to ale neznamenalo. Sousední šlechta totiž nebyla schopna konkurovat ve výrobě piva. Situace se změnila v roce 1548 po konfiskaci městského majetku, neboť nymburští várečníci přestali mít levný zdroj obilí z městských statků a byli nuceni pšenici a ječmen kupovat z okolních panství. Do začátku třicetileté války výstav klesal, ale ne tak razantně, jak by odpovídalo situaci. Okolní vrchnosti totiž stále ještě neměly k dispozici potřebnou výrobní kapacitu. Postupně se možnosti vrchnostenských pivovarů, zejména lyského a poděbradského, vyrovnávaly královskému městu Nymburku. Výsadní postavení město ztratilo za třicetileté války.

Abstract Introduction Multilayer materials of cultural heritage such as historical materials and artwork are analysed as cross-section samples using microscopy and FTIR microscopy. Most commonly, these samples are embedded in synthetic resin, ground and polished. During this process, there is a high potential for the synthetic resin to contaminate the sample. The resin penetrates into the open pores or cracks in the sample, or solvent of the resin can partially dissolve some layer of the analysed sample. In both cases, the presence of synthetic resin significantly distorts the results of analysis, particularly the analysis of peripheral layers, which are of course the most contaminated. Interpretation of the FTIR spectra of individual layers is very difficult; it can be ambiguous and largely subjective. Moreover, analysed layers are usually a mixture of substances, where the studied substance (for example organic binder) is present as a minor component. Results Due to potential contamination of samples processed with the aforementioned method, a new method of preparing samples is desired, one in which contamination of the sample caused by the embedding material would be eliminated. This paper compares the advantages and limits of different methods of sample preparation before analysis; methods which would eliminate the contamination of analysed materials. Various analytical methods and different procedures used for sample preparation are discussed. The most successful of the tested insulation methods proved to be that of pressing the sample in KBr pellet, gold sputtering and carbon coating or anticipatory treatment by cyclododecane solution before embedding the sample in synthetic resin. Conclusion It can be concluded that these procedures eliminate contamination of the analysed sample regardless of its nature and morphology. This conclusion was confirmed by an analysis of real samples.