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Application of Environmental Scanning Electron Microscopy (ESEM) in the field of miniatures´ analysis: methodology for specific use in miniature painting research
Hradil, David ; Hradilová, J. ; Neděla, Vilém ; Tihlaříková, Eva
The methodology deals with a completely new, unused procedure of non-invasive analysis of painted portrait miniatures, namely an environmental scanning electron microscope with energy-dispersive X-rays. spectrometer(EREM-EDS). EREM, unlike the conventional scanning electron microscope (REM), allows the analysis of ivory painting, which is not possible in a vacuum or low gas pressure environment, where there is a risk of deformation and damagedue to drying of this biological material. The methodology is divided into two parts - the first describes the study of morphological details at high magnification (eg. the possibility of distinguishing different types of biological substrates), the second is the implementation of elemental analysis in high spatial resolution.
Metodika pro obrazovou a morfologickou analýzu miniaturních portrétů
Pech, Michal ; Hradilová, Janka ; Hradil, David
The methodology is intended primarily for laboratories and restorers; it describes basic non-invasive methods of image and morphological analysis suitable for the study of miniature painting. Commonly used methods of restoration research designed for the study of easel and panel paintings can also be applied to the study of miniatures; however, their small size, materials, and techniques impose a number of limitations. Traditional invasive methods associated with sampling cannot be used when examining miniatures. The methodology describes how to adapt commonly used methods, such as visible and UV-light imaging, infrared reflectometry and digital radiography, to the study of miniatures. X-ray fluorescence scanning (MA-XRF spectroscopy) is proving to be a particularly important tool for pigment identification and the study of miniature painting techniques, with its ability to produce high-resolution elemental maps. In the future, it can be expected that this still not widely used method, which combines the advantages of image and analytical methods of exploration, will be rapidly developing.
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Bodová neinvazivní analýza miniatur přenosnými a laboratorními nástroji: metodika pro specifické použití ve výzkumu miniaturního malířství
Kočí, Eva ; Bezdička, Petr ; Hradil, David ; Garrappa, Silvia ; Hradilová, Janka ; Pech, Michal
The methodology brings a comprehensive procedure of non-invasive materials analysis of painted miniature artworks, while it is divided into two subsequent parts. In the first part, it describes the use of portable devices for spectroscopic analysis of miniatures, and in the second, it deals with the application of a new methodological procedure for phase/structural materials analysis based on X-ray powder diffraction. The methodology thus includes the following procedures: (i) determination of the elemental composition of the colour layer by the x-ray fluorescence analysis, (ii) identification of binders and other organic compounds using infrared spectroscopy (FT-IR), and finally (iii) phase/mineralogical and structural analysis to describe in more detail the pigments used and processes of their degradation. As part of this last step, the limits of Raman spectroscopy (RS) and the advantages of powder X-ray diffraction and micro-diffraction (XRPD and micro-XRPD) are described, which include greater gentleness to the analysed objects. A very complete and above all non-invasive methodological procedure for the analysis of miniatures is thus offered, which uses the complementarity of individual methods and which can be partly applied already in situ (directly in collection institutions) and partly at specialized workplaces.
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Mineralogical analysis of historical paintings
Čermáková, Zdeňka ; Hradil, David (advisor) ; Kanický, Viktor (referee) ; Artioli, Gilberto (referee)
Historical painted works of art have a very complex inner structure. The period painting technique led to the execution of a ground layer followed by several layers of underpainting and a top paint layer, over which a layer of glaze has been applied to increase the resistance to external wear. Each of these colour layers is composed of a dye or a pigment (or their mixture) bound by organic binder. Throughout the history, pigments were commonly prepared from minerals, either extracted from natural deposits or created artificially. In these heterogeneous layers containing both inorganic and organic components, undesirable degradation changes either driven by processes taking place directly in the colour layer or influenced by external agents may occur. Mineralogical approach, which focuses primarily on the structure of studied pigments, helps in the clarification of the occurring processes, in the determination of conditions leading to degradation as well as in the identification of original/degradation phases. Furthermore, it can be profitably applied in the micro- analysis of mineral pigments present in tiny micro-samples obtained from works of art, contributes to the artwork's provenance/authorship studies and the determination of regional provenance of the employed mineral pigments. This Ph.D....
Characterisation and chemical modification of halloysites
Vašutová, Vlasta ; Hradil, David (advisor) ; Pospíšil, Miroslav (referee)
Twelve halloysites from different sources in Slovakia, Turkey, China, New Zealand and U.S.A. have been characterized by combination of analytical methods together with the commercial sample of halloysite supplied by Sigma-Aldrich. The aim of this work was to select suitable candidates for to be used as carriers of porphyrine photoactive molecules. In nature, the formation of halloysite is related to the weathering of magmatic rocks or to the hydrothermal alteration of volcanic rocks, frequently in the contact with limestones. Halloysite belong to the kaolinite group, but, contrarily to kaolinite, it contains molecules of water in the interlayer space. It occurs in two forms: hydrated halloysite (10 ?) and dehydrated halloysite (7 ?).Dehydrated halloysites contain more admixtures than hydrated ones ? typically kaolinite, quartz, cristobalite, alunite, gibbsite and in one case also potassium mica. In samples containing both dehydrated halloysite and kaolinite their 001 diffractions overlap. Interaction with formamide was used in these cases to increase the interlayer space of halloysite and thus shift its basal diffraction to lower angles. The basal 001 diffraction of kaolinite after this treatment remains on 7 ?. Silver thiourea method (AgTU) was used to measure the cationic exchange capacity (CEC). Silver...
Aplikace environmentální rastrovací elektronové mikroskopie (EREM) v oboru analýzy miniatur: metodika pro specifické použití ve výzkumu miniaturního malířství
Hradil, David ; Hradilova, Janka ; Neděla, Vilém ; Tihlaříková, Eva
The methodology deals with a completely new, unused procedure of non-invasive analysis of painted portrait miniatures, using environmental scanning electron microscope with an energy-dispersive X-ray spectrometer (ESEM-EDS). ESEM, unlike the conventional scanning electron microscope (SEM), allows the analysis of the painting on the ivory support, which is not possible in the gas pressure approaching the vacuum, where there is a risk of deformation and damage due to the drying of this biological material. Instead of an inert gas (nitrogen, argon), the aim is to use a mixture of nitrogen and water vapor at a defined pressure corresponding to the required relative humidity in the measuring chamber. This enables a completely non-invasive analysis of painted miniature objects on organic types of supports. This methodology is divided into two parts: morphological analysis and elemental composition analysis. The first case involves the study of morphological details at high magnification (e. g. the possibility of distinguishing different types of supports or characterizing their microstructure). The second part describes the implementation of elemental analysis in high spatial resolution (distinction of individual pigment grains).
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Lead soaps in paintings: symptoms and the role of humidity
Garrappa, Silvia ; Švarcová, Silvie ; Kočí, Eva ; Hradilová, J. ; Bezdička, Petr ; Hradil, David
In this study, an overview of the symptoms of lead soaps reported in artworks in combination\nwith the study of the role of humidity on the formation of these degradation products have\nbeen thoroughly investigated. The use of optical microscopy, scanning electron microscopy\n(SEM) in combination with Fourier-transform infrared spectroscopy (FTIR) proved to be an\nefficient analytical approach to highlight both the saponified area of artworks’ samples and the\nformation of metal carboxylates within mock-up model systems. Optical microscopy revealed\nto be very useful for the first screening of samples embedded in resin, while SEM helped in\nthe detection and distribution of elements within the cross-sections. On the other hand, FTIR\nmicroscope proved to be a very powerful instrument for high-resolution point measurements\nperformed in the attenuated total reflection mode (ATR) mode with mercury-cadmium-telluride\n(MCT) detector, as well as for chemical imaging of larger area of both artworks’ and mock-up\nsamples performed in the ATR mode with focal plane arrays (FPA) detector. This study provides\nnew useful insights contributing to better understanding of factors affecting the paints‘ stability,\nwhich is neccesary for developing new efficient strategies for preservation and restoration of\nfatty-based painted artworks.
Non-invasive material and traceological research of the stone head from Celtic settlement Závist near Prague
Cihla, M. ; Trefný, M. ; Drda, Petr ; Hradil, David ; Hradilová, J.
The sandstone head sculpture from the hillfort of Závist in the southern periphery of Prague has been subjected to a non-invasive survey by mechanoscopic and analytical approaches. A 3D model of a sculpture has been created using laser scanning and photogrammetry. A reconstruction of stonemason's working tools was derived from longitudinal and transversal sections of the traces on the head's surface. Further screening of the surface by handheld X-ray fluorescence identified increased contents of lead and tin suggesting a former intentional coloring of the sculpture's surface. Traces of gold could indicate that the surface was gilded. It was confirmed that the sculpture was originally not a part of a human figure, but was intended to represent only a self-standing head. The way of making as well as the nature of the original surface treatment has excluded the possibility that the stone head from Závist was a modern replica.
The origin issue of the head of John the Baptist from Tajov
Hradilová, J. ; Bezúchová, E. ; Hradil, David ; Šídová, K.
The significant work of art, the Head of John the Baptist from Tajov, from the Museum of Central Slovakia in Banska Bystrica, which is probably part of the works of Niclaus Gerhaert von Leiden (1420/30 - 1475), was subject to conservation as well as detailed material analysis - first using non-invasive methods (radiography computer tomography, X-ray fluorescence), then laboratory analysis of taken samples (elemental and phase analysis, analysis of organic binders, dendrochronology, radiocarbon dating). The specific painting technique was described. Gilding of the head was performed without any ground only on brown preparatory layer for oil gilding (mixtion), however, the incarnates with an oily binder did contain a light dolomitic ground layer. The blood drops painting employed madder lake including sheep wool shearlings. The work consists of two parts - the head and the bowl, which was understood not to be original. Both parts are made from poplar wood. The results of the dating indicate that the head was created in the second half of the 15th century. The bowl could have been added later, but no later than the beginning of the 16th century. Its inclusion may have happened (albeit it is less probable) in the 17th century, but any period of time after that can be ruled out. The original colouring of the bowl was different the earth pigments of specific composition used in the ground layer imitated terracotta - a clay bowl. Based on the location of the existing hanging points the head was probably on display occasionally in a vertical position with a slight bottom view of 45 degrees.
Mineralogical analysis of historical paintings
Čermáková, Zdeňka ; Hradil, David (advisor) ; Kanický, Viktor (referee) ; Artioli, Gilberto (referee)
Historical painted works of art have a very complex inner structure. The period painting technique led to the execution of a ground layer followed by several layers of underpainting and a top paint layer, over which a layer of glaze has been applied to increase the resistance to external wear. Each of these colour layers is composed of a dye or a pigment (or their mixture) bound by organic binder. Throughout the history, pigments were commonly prepared from minerals, either extracted from natural deposits or created artificially. In these heterogeneous layers containing both inorganic and organic components, undesirable degradation changes either driven by processes taking place directly in the colour layer or influenced by external agents may occur. Mineralogical approach, which focuses primarily on the structure of studied pigments, helps in the clarification of the occurring processes, in the determination of conditions leading to degradation as well as in the identification of original/degradation phases. Furthermore, it can be profitably applied in the micro- analysis of mineral pigments present in tiny micro-samples obtained from works of art, contributes to the artwork's provenance/authorship studies and the determination of regional provenance of the employed mineral pigments. This Ph.D....

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