Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2016
Twenty one mock-up samples containing inorganic pigments primarily used at the turn of the 19th a... more Twenty one mock-up samples containing inorganic pigments primarily used at the turn of the 19th and 20th century were selected for comparative study and measured by micro-Raman and portable Raman spectrometers. They included pure grounds (chalk-based, earth-based and lithopone-based), grounds covered by resin-based varnish, and different paint layers containing mixtures of white, yellow, orange, red, green, blue and black pigments, usually in combination with white pigments (titanium, zinc and barium whites or chalk). In addition, ten micro-samples obtained from seven paintings of two world-famous modern painters Edvard Munch and František Kupka have been investigated. Infrared reflection spectroscopy (FTIR), portable X-ray fluorescence (XRF) and scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) were used as supplementary methods. The measurements showed that blue pigments (ultramarine, Prussian blue and azurite), vermilion and ivory black in mixture with whites provided characteristic Raman spectra, while Co-, Cd- and Cr- pigments' bands were suppressed by fluorescence. The best success rate of micro-Raman spectroscopy has been achieved using the 780nm excitation, however, the sensitivity of this excitation laser in a portable Raman instrument significantly decreased. The analyses of micro-samples of paintings by E. Munch and F. Kupka showed that micro-Raman spectroscopy identified pigments which would remain unidentified if analyzed only by SEM-EDS (zinc yellow, Prussian blue). On the other hand, chromium oxide green and ultramarine were not detected together in a sample due to overlap of their main bands. In those cases, it is always necessary to complement Raman analysis with other analytical methods.
In this paper, we present an application of digital image processing algorithms for the process o... more In this paper, we present an application of digital image processing algorithms for the process of fresco restoration. Modern methods for image preprocessing and evaluation such as image registration, image fusion, and image segmen-tation are applied on images of the fresco, obtained in differ-ent modalities (visual and ultraviolet spectra) and at different times. Moreover, local chemical analyzes are taken into ac-count during the image analysis. The robustness of proposed algorithms should be high due to the bad state of the fresco. Achieved results can give to art restorers better insight into the evolution of the fresco aging and in this way a proper conservation method can be chosen. Developed methods are illustrated by generated output images.
In our paper we introduce comprehensive solution for pro-cessing and archiving information about ... more In our paper we introduce comprehensive solution for pro-cessing and archiving information about artwork specimens used in the course of art restoration -Nephele. The infor-mation processing based on image data is used in the proce-dure of identification of pigment and binder present in the art-work, which is very important issue for restorers. Proposed approach geometrically aligns images of microscopic cross-sections of artwork color layers -image registration method based on mutual information, and then creates preliminary color layer segmentation -modified k-means clustering. The archiving part of the Nephele enables creating database en-tries for painting materials research database, their storage, and creating text-based queries. In addition to these tradi-tional database functions, advanced report retrieval is sup-ported; based on the similarity of image data, comparing either the ultraviolet and visual spectra images (using co-occurence matrices and color similarity function...
On the base of materials and art-historic traits a Gothic panel painting from the collections of ... more On the base of materials and art-historic traits a Gothic panel painting from the collections of the Moravian Gallery in Brno has been included among 15th century South German works. Key words:Gothic paintings * materials analysis * double-layer ground
This contribution focuses on the identification of the materials and technological characteristic... more This contribution focuses on the identification of the materials and technological characteristics of painting workshops active in Transylvania in the first decades of the sixteenth century. The first group of workshops considered was located in Sighişoara, one of which is known to have been run by Johannes Stoss. The altarpieces in the second group are attributed to the workshop of Vincentius, a painter in Sibiu, who signed and dated several altarpieces and one fresco painting still preserved in the region. Extensive research carried out during the past five years has brought to light important new evidence regarding particular features and similarities in the preparatory layers, gilding techniques and paint application. Complementary analytical methods and close visual examination were used to identify the structure and the composition of the grounds, poliments and precious metals on the painted panels. The results point to technological features common to the workshops, such as r...
The representation of rich brocade fabrics was one of the main and most striking features of Euro... more The representation of rich brocade fabrics was one of the main and most striking features of European medieval paintings. What we see today is the impressive result of the artist’s skills and the commissioner’s preferences. To achieve this effect, medieval artists developed a large variety of materials and techniques. This paper presents the results of an integrated approach to the investigation of the techniques used by the painting workshops in Transylvania for the imitation of brocade fabrics. The investigation is carried out on a group of 12 largely unstudied Late Gothic – Early Renaissance altarpieces built between 1450 – 1540 in German and Hungarian communities, these being some of the oldest panel paintings preserved in Romania.
Within the investigation of historical paintings, portable X-ray fluorescence (XRF) can successfu... more Within the investigation of historical paintings, portable X-ray fluorescence (XRF) can successfully be used for a non-invasive screening that involves basically describe inorganic pigments and locate repaints, retouches and surface alterations. In combination with imaging techniques, e.g., IR-reflectography, such a screening could effectively reduce further sampling and select areas important for detailed investigations. In a case of paintings, the description of layer stratigraphy and painting technique is limited when using only non-invasive tools. Elements located in underpainting and ground layers are usually found as accompanying in whole measured area. Within our study, hand-held XRF was used for the screening of a cycle of Early Romanesque frescoes in the single nave church of St. George at Kostoľany pod Tribečom, Slovakia. After the first stage of the pre- restoration research coming out from non-invasive measurements and microanalysis of very limited amount of samples, we ...
ABSTRACT Vivianite (Fe3(PO4)2·8H2O) is a rare blue historical pigment, which can be profitably us... more ABSTRACT Vivianite (Fe3(PO4)2·8H2O) is a rare blue historical pigment, which can be profitably used in authorship ascription or copy identification. However, its tendency to degrade complicates its proper identification in paint layers. Reference vivianite mineralogical samples were analysed in order to compare and to test the limits of structural analyses on possibly degraded vivianite samples (X-ray diffraction and vibrational spectroscopies). The same methods, in their μ-configuration, were tested on micro-samples of the paintings and their limits evaluated. A sedimentary origin of the pigment has been suggested. Vivianite was detected in various works by Jean George de Hamilton (1672–1737) and in a Late Gothic Transylvanian altarpiece.
ABSTRACT Pre-Romanesque murals at Kostoľany pod Tríbečom, Slovakia, have been investigated by por... more ABSTRACT Pre-Romanesque murals at Kostoľany pod Tríbečom, Slovakia, have been investigated by portable X-ray fluorescence and by microanalytical methods to identify painting materials (pigments and binders), and to explain the degradation of colours. Today, missing green and blue shades have been reconstructed according to residual concentrations of Cu, which correspond to copper chlorides—products of salt corrosion of the copper carbonates azurite and/or malachite, accelerated by micro-organisms. As confirmed by powder X-ray microdiffraction, original minium (Pb3O4) has been transformed to brown–black plattnerite (PbO2). In increased humidity, even insoluble pigments are washing down from the walls and the intensity of colours further diminishes.
ABSTRACT While the most famous historical green earth deposits in Italy and Cyprus were exception... more ABSTRACT While the most famous historical green earth deposits in Italy and Cyprus were exceptionally rich in celadonite, the deposits near Kadaň, Czech Republic, consisted of thin Fe-rich celadonite impregnations accompanied by interstratified celadonite/smectite. In superimposed tuffs, smectites become prevalent and their colour changes from forest to olive green. Powder X-ray microdiffraction and infrared microspectroscopy permit us to distinguish between green earth minerals in microsamples taken from works of art. The Ti contents and the Fe/Mg ratios help to indicate the presence of Bohemian green earth from Kadaň. We found this material in local 18th-century works of art and also in paintings by Anton Kern (1709–47).
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2016
Twenty one mock-up samples containing inorganic pigments primarily used at the turn of the 19th a... more Twenty one mock-up samples containing inorganic pigments primarily used at the turn of the 19th and 20th century were selected for comparative study and measured by micro-Raman and portable Raman spectrometers. They included pure grounds (chalk-based, earth-based and lithopone-based), grounds covered by resin-based varnish, and different paint layers containing mixtures of white, yellow, orange, red, green, blue and black pigments, usually in combination with white pigments (titanium, zinc and barium whites or chalk). In addition, ten micro-samples obtained from seven paintings of two world-famous modern painters Edvard Munch and František Kupka have been investigated. Infrared reflection spectroscopy (FTIR), portable X-ray fluorescence (XRF) and scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) were used as supplementary methods. The measurements showed that blue pigments (ultramarine, Prussian blue and azurite), vermilion and ivory black in mixture with whites provided characteristic Raman spectra, while Co-, Cd- and Cr- pigments' bands were suppressed by fluorescence. The best success rate of micro-Raman spectroscopy has been achieved using the 780nm excitation, however, the sensitivity of this excitation laser in a portable Raman instrument significantly decreased. The analyses of micro-samples of paintings by E. Munch and F. Kupka showed that micro-Raman spectroscopy identified pigments which would remain unidentified if analyzed only by SEM-EDS (zinc yellow, Prussian blue). On the other hand, chromium oxide green and ultramarine were not detected together in a sample due to overlap of their main bands. In those cases, it is always necessary to complement Raman analysis with other analytical methods.
In this paper, we present an application of digital image processing algorithms for the process o... more In this paper, we present an application of digital image processing algorithms for the process of fresco restoration. Modern methods for image preprocessing and evaluation such as image registration, image fusion, and image segmen-tation are applied on images of the fresco, obtained in differ-ent modalities (visual and ultraviolet spectra) and at different times. Moreover, local chemical analyzes are taken into ac-count during the image analysis. The robustness of proposed algorithms should be high due to the bad state of the fresco. Achieved results can give to art restorers better insight into the evolution of the fresco aging and in this way a proper conservation method can be chosen. Developed methods are illustrated by generated output images.
In our paper we introduce comprehensive solution for pro-cessing and archiving information about ... more In our paper we introduce comprehensive solution for pro-cessing and archiving information about artwork specimens used in the course of art restoration -Nephele. The infor-mation processing based on image data is used in the proce-dure of identification of pigment and binder present in the art-work, which is very important issue for restorers. Proposed approach geometrically aligns images of microscopic cross-sections of artwork color layers -image registration method based on mutual information, and then creates preliminary color layer segmentation -modified k-means clustering. The archiving part of the Nephele enables creating database en-tries for painting materials research database, their storage, and creating text-based queries. In addition to these tradi-tional database functions, advanced report retrieval is sup-ported; based on the similarity of image data, comparing either the ultraviolet and visual spectra images (using co-occurence matrices and color similarity function...
On the base of materials and art-historic traits a Gothic panel painting from the collections of ... more On the base of materials and art-historic traits a Gothic panel painting from the collections of the Moravian Gallery in Brno has been included among 15th century South German works. Key words:Gothic paintings * materials analysis * double-layer ground
This contribution focuses on the identification of the materials and technological characteristic... more This contribution focuses on the identification of the materials and technological characteristics of painting workshops active in Transylvania in the first decades of the sixteenth century. The first group of workshops considered was located in Sighişoara, one of which is known to have been run by Johannes Stoss. The altarpieces in the second group are attributed to the workshop of Vincentius, a painter in Sibiu, who signed and dated several altarpieces and one fresco painting still preserved in the region. Extensive research carried out during the past five years has brought to light important new evidence regarding particular features and similarities in the preparatory layers, gilding techniques and paint application. Complementary analytical methods and close visual examination were used to identify the structure and the composition of the grounds, poliments and precious metals on the painted panels. The results point to technological features common to the workshops, such as r...
The representation of rich brocade fabrics was one of the main and most striking features of Euro... more The representation of rich brocade fabrics was one of the main and most striking features of European medieval paintings. What we see today is the impressive result of the artist’s skills and the commissioner’s preferences. To achieve this effect, medieval artists developed a large variety of materials and techniques. This paper presents the results of an integrated approach to the investigation of the techniques used by the painting workshops in Transylvania for the imitation of brocade fabrics. The investigation is carried out on a group of 12 largely unstudied Late Gothic – Early Renaissance altarpieces built between 1450 – 1540 in German and Hungarian communities, these being some of the oldest panel paintings preserved in Romania.
Within the investigation of historical paintings, portable X-ray fluorescence (XRF) can successfu... more Within the investigation of historical paintings, portable X-ray fluorescence (XRF) can successfully be used for a non-invasive screening that involves basically describe inorganic pigments and locate repaints, retouches and surface alterations. In combination with imaging techniques, e.g., IR-reflectography, such a screening could effectively reduce further sampling and select areas important for detailed investigations. In a case of paintings, the description of layer stratigraphy and painting technique is limited when using only non-invasive tools. Elements located in underpainting and ground layers are usually found as accompanying in whole measured area. Within our study, hand-held XRF was used for the screening of a cycle of Early Romanesque frescoes in the single nave church of St. George at Kostoľany pod Tribečom, Slovakia. After the first stage of the pre- restoration research coming out from non-invasive measurements and microanalysis of very limited amount of samples, we ...
ABSTRACT Vivianite (Fe3(PO4)2·8H2O) is a rare blue historical pigment, which can be profitably us... more ABSTRACT Vivianite (Fe3(PO4)2·8H2O) is a rare blue historical pigment, which can be profitably used in authorship ascription or copy identification. However, its tendency to degrade complicates its proper identification in paint layers. Reference vivianite mineralogical samples were analysed in order to compare and to test the limits of structural analyses on possibly degraded vivianite samples (X-ray diffraction and vibrational spectroscopies). The same methods, in their μ-configuration, were tested on micro-samples of the paintings and their limits evaluated. A sedimentary origin of the pigment has been suggested. Vivianite was detected in various works by Jean George de Hamilton (1672–1737) and in a Late Gothic Transylvanian altarpiece.
ABSTRACT Pre-Romanesque murals at Kostoľany pod Tríbečom, Slovakia, have been investigated by por... more ABSTRACT Pre-Romanesque murals at Kostoľany pod Tríbečom, Slovakia, have been investigated by portable X-ray fluorescence and by microanalytical methods to identify painting materials (pigments and binders), and to explain the degradation of colours. Today, missing green and blue shades have been reconstructed according to residual concentrations of Cu, which correspond to copper chlorides—products of salt corrosion of the copper carbonates azurite and/or malachite, accelerated by micro-organisms. As confirmed by powder X-ray microdiffraction, original minium (Pb3O4) has been transformed to brown–black plattnerite (PbO2). In increased humidity, even insoluble pigments are washing down from the walls and the intensity of colours further diminishes.
ABSTRACT While the most famous historical green earth deposits in Italy and Cyprus were exception... more ABSTRACT While the most famous historical green earth deposits in Italy and Cyprus were exceptionally rich in celadonite, the deposits near Kadaň, Czech Republic, consisted of thin Fe-rich celadonite impregnations accompanied by interstratified celadonite/smectite. In superimposed tuffs, smectites become prevalent and their colour changes from forest to olive green. Powder X-ray microdiffraction and infrared microspectroscopy permit us to distinguish between green earth minerals in microsamples taken from works of art. The Ti contents and the Fe/Mg ratios help to indicate the presence of Bohemian green earth from Kadaň. We found this material in local 18th-century works of art and also in paintings by Anton Kern (1709–47).
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