Showing papers in "Studies in Conservation in 2015"
TL;DR: The use of volatile organic compounds (VOCs) is a useful method for understanding the chemical processes involved in polymer degradation and for the identification of materials as discussed by the authors, and VOC analysis also has potential as a technique for bulk material identification, as a complementary tool t...
Abstract: There is an acknowledged need for improved conservation of plastic and rubber objects within collections, including improved methods of condition assessment, material identification, and better understanding of material degradation. This reflects the inherent instability and wide-ranging formulations of many such objects and also the relative lack of knowledge in this field. Analysis of volatile organic compounds (VOCs) is a useful method for understanding the chemical processes involved in polymer degradation and for the identification of materials. Conservators and curators have used odor analysis to identify historical plastics for many years, and techniques ranging from acid detection strips to laboratory-based techniques such as solid-phase microextraction-gas chromatography-mass spectrometry have been used to characterize plastic and rubber materials and to understand their degradation. VOC analysis also has potential as a technique for bulk material identification, as a complementary tool t...
48 citations
TL;DR: In this paper, conditions for the stability of the red color of cinnabarite and its reaction to environmental factors, such as radiation or halogens, are evaluated from various viewpoints, and the pigment's structural stability is viewed in connection with adjacent pigments, glues, and substrate.
Abstract: In the majority of cases, the red color of cinnabar on objects of cultural heritage is well preserved, though turning black is often claimed and has been the subject of investigations. To evaluate conditions for the stability of the pigment and understand the reactions, in this paper the problem is approached from various viewpoints. First of all the natural form cinnabarite is compared with the artificially prepared pigment vermilion. This establishes a differentiation of types in terms of quality, depending on structural impurities. With regard to the pigment's reactions influencing the discoloration, the most commonly mentioned environmental factors, such as radiation or halogens, are evaluated. In relation to various usages, the pigment's structural stability is then viewed in connection with adjacent pigments, glues, and the substrate, which may lead to a brown or black coloration or even the release of mercury, whereas the color is preserved in most cases when used on lime or in ink and lacq...
40 citations
TL;DR: In this paper, the authors compared the effectiveness of nano-second laser ablation with traditional cleaning procedures for the removal of painted graffiti from the surface of monuments, and found that the laser system used for cleaning was a ns Nd:YAG, irradiating at 1064, 532, and 355 nm.
Abstract: This contribution discusses the analysis of polymeric paint layers and the removal of graffiti from historical buildings and sculptures. The main objective of the research is to compare the effectiveness of nano-second (ns) laser ablation with traditional cleaning procedures for the removal of painted graffiti from the surface of monuments. The vast number of various aerosol paints used for graffiti which contain different binders, solvents, and pigments does not allow the use of a single or universal cleaning method. In this study the efficacy of laser ablation was compared with chemical and mechanical cleaning methods. The laser system used for cleaning was a ns Nd:YAG, irradiating at 1064, 532, and 355 nm. Laser cleaning tests were performed on samples of limestone, sandstone, plaster, and brick covered with black, white, and red graffiti paints based on nitrocellulose, acrylic, and alkyd resins. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy with energy-dispers...
35 citations
TL;DR: A review of the chemistry and deterioration of keratin and past approaches to the identification of kithatinous archaeological remains is given in this paper, which describes the formation of horn, hoof, baleen, and tortoiseshell and demonstrates how identification can be achieved by combining visual observation under low power magnification with an understanding of the structure and characteristic deterioration of these materials.
Abstract: Despite being widely utilized in the production of cultural objects, keratinous hard tissues, such as horn, baleen, and tortoiseshell, rarely survive in archaeological contexts unless factors combine to inhibit biodeterioration. Even when these materials do survive, working, use, and diagenetic changes combine to make identification difficult. This paper reviews the chemistry and deterioration of keratin and past approaches to the identification of keratinous archaeological remains. It describes the formation of horn, hoof, baleen, and tortoiseshell and demonstrates how identification can be achieved by combining visual observation under low-power magnification with an understanding of the structure and characteristic deterioration of these materials. It also demonstrates how peptide mass fingerprinting of the keratin can be used to identify keratinous tissues, often to species, even when recognizable structural information has not survived.
30 citations
TL;DR: A gel-like system for the treatment of art has been prepared from partially hydrolyzed poly(vinyl acetate), borax, and large fractions of ethanol, isopropyl alcohol, n-propyl alcohol and acetone as discussed by the authors.
Abstract: A versatile gel-like system for the treatment of art has been prepared from partially hydrolyzed poly(vinyl acetate), borax, and large fractions of ethanol, isopropyl alcohol, n-propyl alcohol, and acetone. Variables such as the concentrations of the two gelating components, the degree of hydrolysis and molecular weight of the polymer, and the type of liquid gelated were investigated to establish formulations of gels with physical and chemical properties that are best suited for specific applications. The gels were designed to have an elastic character that allows them to conform to the topography of complex surfaces and be removed with ease by being lifted from the surface. Results from fluorescence studies demonstrated that the solvent is constrained within the area of the gel, allowing for localized treatment. Polymer and boron residues were not detected after cleaning tests on acrylic and dammar test paint-outs, and on two oil paintings with degraded surface coatings. The efficacy of the clean...
28 citations
TL;DR: In this paper, the surface modifications of chestnut (Castanea sativa mill) wood by reflectance spectrophotometry and Fourier transform infrared spectroscopy were studied to understand the mechanisms that cause changes and suggest possible solutions to avoid degradation phenomena.
Abstract: The aim of this work is to study the surface modifications of chestnut (Castanea sativa Mill.) wood by reflectance spectrophotometry and Fourier transform infrared spectroscopy (FTIR) in order to understand the mechanisms that cause changes and to suggest possible solutions to avoid degradation phenomena. The experimental data were statistically treated to evaluate their significance. Concerning the surface protection of wood, starting from the results obtained by testing different commercial products, attention was focused on a novel organic preservative/consolidant product (Linfoil®) that has attracted great interest in the field of conservation of wooden artifacts. Color monitoring showed that wood surface color undergoes an important variation due to photoirradiation, occurring within the first 24 hours and mainly due to L* decrease and b* increase. Though the protective treatment modifies wood color, nevertheless the product tested seems to protect the wood surface by reducing photoyellowing. FTIR an...
26 citations
TL;DR: The authors discusses how embodied heritage values operate within a context of heritage sites, and tangible and intangible embodiments of what is valued as heritage, and questions the claim that "Eastern" and "Western" philosophies of conservation are very different, and that they can be characterized as being concerned with intangible and tangible heritage, respectively.
Abstract: This contribution discusses how embodied heritage values operate within a context of heritage sites, and tangible and intangible embodiments of what is valued as heritage. This is partly intended to re-contextualize ideas of material and materiality that have recently undergone reconsideration in conservation and heritage discourse. The paper questions the claim that ‘Eastern’ and ‘Western’ philosophies of conservation are very different, and that they can be characterized as being concerned with intangible and tangible heritage, respectively. This is based on the assertion that influential preservation doctrines are as much a product of the context and practical situations as they are a product of different philosophies and cultures. Well-known examples from East and West are discussed to highlight the similarities, as opposed to the differences, in approaches. The article goes on to discuss the UNESCO definition of intangible heritage (2003), which conflates the intangible embodiment of values w...
26 citations
TL;DR: In this paper, active infrared thermography was applied to study a seventeenth-century painting on paper, namely the Chigi's family tree, housed at Palazzo Chigi in Ariccia (Rome).
Abstract: In this work, active infrared thermography was applied to study a seventeenth-century painting on paper, namely the Chigi's family tree, housed at Palazzo Chigi in Ariccia (Rome). Thermography was performed before and after restoration to obtain information used in planning the restoration and also to assess its effectiveness. Infrared thermography provided important information on the artifact structure, areas of damage, structural defects, and the state of adhesion between different layers of the composite artifact before and after the treatment.
26 citations
TL;DR: In this paper, an investigation for light exposure on pigments in low-oxygen environments (in the range 0-5% oxygen) was conducted using a purpose-built automated microfadometer for a large sample set including multiple samples of traditional watercolour pigments from nineteenth-century and twentieth-century sources, selected for concerns over their stability in anoxia.
Abstract: An investigation for light exposure on pigments in low-oxygen environments (in the range 0–5% oxygen) was conducted using a purpose-built automated microfadometer for a large sample set including multiple samples of traditional watercolour pigments from nineteenth-century and twentieth-century sources, selected for concerns over their stability in anoxia. The pigments were prepared for usage in watercolour painting: ground and mixed in gum Arabic and applied to historically accurate gelatine glue-sized cotton and linen-based papers. Anoxia benefited many colorants and no colorant fared worse in anoxia than in air, with the exception of Prussian blue and Prussian green (which contains Prussian blue). A Prussian blue sampled from the studio materials of J.M.W. Turner (1775 − 1851) was microfaded in different environments (normal air (20.9% oxygen) 0, 1, 2, 3.5, or 5% oxygen in nitrogen) and the subsequent dark behaviour was measured. The behaviour of the sample (in normal air, anoxia, and 5% oxygen in nitrogen) proved to be consistent with the 55 separately sourced Prussian blue samples. When exposed to light in 5% oxygen in nitrogen, Prussian blue demonstrated the same light stability as in air (at approximately 21°C and 1 atmosphere). Storage in 5% oxygen is proposed for ‘anoxic’ display of paper-based artworks that might contain Prussian blue, to protect this material while reducing light-induced damage to other components of a watercolour, including organic colorants and the paper support.
24 citations
TL;DR: In this paper, the use of macro-X-ray fluorescence (XRF) and optical coherence tomography (OCT) in the inspection of an illuminated manuscript is reported for the first time.
Abstract: Macro-X-ray fluorescence (XRF) is a newly commercially available research tool very useful in the examination of artwork. Its novelty lies in its ability to create maps of the distribution of chemical elements on scales of a few milimetres. In this contribution, its use together with optical coherence tomography (OCT) in the inspection of an illuminated manuscript is reported for the first time. The former technique is used both for mapping the elemental distribution over large parts of the folios – including illuminated initials – and for quantitative analysis of the composition of the smalt pigment, as well as of changes in the composition of iron–gall ink at different pages. The latter, by providing cross-sectional images of painted details, helps in interpreting the XRF results. All of the results shown relate to the examination of a late sixteenth-century-illuminated parchment manuscript (a gradual) originating from the Convent of the Benedictine Sisters in Lviv in the Ukraine.
23 citations
TL;DR: Using the MOLAB® non-invasive analytical mobile laboratory, this article studied a finely illuminated sixteenth-century Persian manuscript at the Fitzwilliam Museum, Cambridge, UK, in collaboration with its Department of Manuscripts and Printed Books.
Abstract: Using the MOLAB® non-invasive analytical mobile laboratory, we studied a finely illuminated sixteenth-century Persian manuscript at the Fitzwilliam Museum, Cambridge, UK, in collaboration with its Department of Manuscripts and Printed Books. Three miniatures belonging to the manuscript, but ascribable to different periods, were analyzed in order to identify similarities and differences in the painting materials and techniques used by Safavid artists over a period of 150 years. The use of multiple analytical techniques indicated a common palette characterizing the three decorative schemes, along with some differences mainly regarding the pigment mixture used to obtain brown hues in the first scheme, as well as the presence of different mixtures in green and dark purple areas in the third scheme.
TL;DR: The possible meanings in conservation of the word authenticity are discussed and some different definitions are briefly evaluated in this paper, where the relationship between cultural heritage charters and how authenticity has been employed in them is explored with examples from the Athen's Charter, The Venice Charter, Nara Document, The San Antonio Declaration, and the UNESCO World Heritage Documents.
Abstract: The possible meanings in conservation of the word authenticity are discussed and some different definitions are briefly evaluated. Recent research showing the brain reacts differently to the concepts of copy and authentic is reviewed. The relationship between cultural heritage charters and how authenticity has been employed in them is explored with examples from the Athen's Charter, The Venice Charter, The Nara Document, The San Antonio Declaration, and the UNESCO World Heritage Documents. Several examples are discussed in the text concerning the interactions between authenticity and restoration, employing the examples of ancient buildings and old master paintings. Some of the important writings on the subject of authenticity by scholars and art historians are reviewed. Criteria which could be used to evaluate the concept of authenticity in different cultural settings are discussed and these are illustrated with case studies taken from restoration carried out on ancient marble sculptures, the Sist...
TL;DR: In this paper, a collection of medieval miniatures (Marcade collection, Treasury of the Saint-Andre Cathedral in Bordeaux, France) dating from the thirteenth to the sixteenth centuries was studied using hyperspectral imaging.
Abstract: Illuminated manuscripts are complex multi-layered and multi-material objects which include a support, preparatory layer, pigment layers, and often highlights. During research into a collection of medieval miniatures (Marcade collection, Treasury of the Saint-Andre Cathedral in Bordeaux, France) dating from the thirteenth to the sixteenth centuries, two Italian illuminations were studied using hyperspectral imaging. This technique associates reflectance spectra with each pixel of the image. The characteristics of the spectral signal in the visible range are used to map pigments comparing reflectance spectra obtain with those of our reference library of medieval pigments. The exploitation of the data cube of the hyperspectral imaging was completed by point analyses such as Raman and X-ray fluorescence spectroscopy commonly used for the identification of pigments. A methodological development as well as preliminary tests on models made according to medieval recipes and materials (parchments, pigments...
TL;DR: In this article, the authors used laser microprofilometry to assess the changes in the surface morphology and time-domain confocal optical coherence tomography (OCT) to evaluate varnish thickness, and integrated with molecular characterization provided by portable Fourier transform infrared spectroscopy operating in reflectance mode, and colorimetric measurements.
Abstract: We report on tests to remove naturally and artificially aged shellac varnish by laser and traditional chemical cleaning from the substrates of mural paintings. Optical tools were used for the evaluation of cleaning processes, in particular laser microprofilometry to assess the changes in the surface morphology and time-domain confocal optical coherence tomography (OCT) to evaluate varnish thickness. The cleaning assessment was integrated with molecular characterization provided by portable Fourier transform infrared spectroscopy operating in reflectance mode, and colorimetric measurements. This complete analytical approach led to optimized laser-based cleaning tests at 1.9 and 2.6 J/cm2 in the presence of isopropanol, which ensured controllable and safe partial removal of shellac varnish without alteration to the substrate morphology.
TL;DR: Terahertz (THz) radiation can be employed onsite for the analysis of museum artifacts related to art conservation science as discussed by the authors, which can be used to reveal their internal structures.
Abstract: Terahertz (THz) radiation can be employed onsite for the analysis of museum artifacts related to art conservation science. This review presents two complementary portable THz imaging devices which have been employed at the Tokyo National Museum (Japan) and at the Museum of Aquitaine (France). A Japanese panel screen, African fetish figures, and a nearly 3500-year-old sealed Egyptian jar were imaged with THz waves, revealing their internal structures.
TL;DR: In this paper, the authors used terahertz time-domain imaging (THz-TDI) in reflection geometry to highlight interfaces between layers in a stratigraphic buildup, and thus makes structural information available in the form of subsurface 3D images and stratigraphy images (B-scans).
Abstract: Scientific analysis of panel paintings could provide key information to art historians and conservators about the composition and condition of the constituent layers. Knowledge of the structure, stratigraphy, and condition of the subsurface layers of these objects is highly relevant to conservation measures, when stability problems such as delamination or internal cracking are considered. Terahertz time-domain imaging (THz-TDI) in reflection geometry is capable of highlighting interfaces between layers in a stratigraphic buildup, and thus makes structural information available in the form of subsurface 3D images and stratigraphic images (B-scans). The technique is contactless and non-invasive, and has been successfully applied to investigation of panel paintings. Regarding gilded panel paintings, the extremely high reflectivity of metals at submillimeter wavelengths generally precludes the transmission of electromagnetic waves through metallic films. Therefore, imaging of subsurface features below gilded ...
TL;DR: In this paper, an analytical survey of corrosion products was carried out using X-ray diffraction, micro-Fourier transform infrared spectroscopy (μFTIR), and μRaman spectrograms.
Abstract: Laser cleaning of bronze artefacts is a very promising conservation approach and its wider distribution would benefit from further studies of its advantages and drawbacks. Some important references are available, yet laser cleaning cannot be considered a traditional method for bronze surfaces. In this paper, we report on the evaluation of cleaning tests performed on an important statue of Napoleon, depicted as Mars the Peacemaker, cast by Righetti in 1811 after a model by Antonio Canova. The sculpture is exposed to the outdoor environment in the main courtyard of the Brera Gallery, Milan, Italy. An analytical survey of corrosion products was carried out using X-ray diffraction, micro-Fourier transform infrared spectroscopy (μFTIR), and μRaman spectroscopy; and scanning electron microscopy with energy-dispersive X-ray spectroscopy analysis was applied to cross-sections. The results showed the ubiquitous presence of brochantite Cu4(SO4)(OH)6. Antlerite Cu3SO4(OH)4 is also occasionally present. Resid...
TL;DR: The BEVA® 371 is a multi-component mixture and was designed specifically for the conservation field using the best technology available at the time as discussed by the authors, however, the main focus of the research was its application as a lining adhesive.
Abstract: Many natural and synthetic products have been used for the consolidation of paint layers, but none have been thoroughly tested for this application. This is apparent for most of the synthetic and semi-synthetic adhesives for conservation, many of which are pure polymer resins and dispersions adapted from other industries. They were not specifically formulated with the appropriate properties for conservation, nor do they take advantage of some of the more recent developments in adhesive technology. BEVA® 371 is unique among adhesives used for consolidation treatments, as it is a multi-component mixture and was designed specifically for the conservation field using the best technology available at the time. However, the main focus of the research was its application as a lining adhesive. Thus, optical properties and stability, specifically color stability, were not thoroughly evaluated even though some lining applications that were first recommended could have benefited from this type of investigati...
TL;DR: In this article, the authors present a review of the examination and analysis of the salt contaminants for their identification and of simulation tests to determine their source(s) and mode of formation since 1990.
Abstract: Salt contamination in the ceramic collection of the Athenian Agora, American School of Classical Studies, Greece, was confronted for the first time by the fulltime conservation staff that was appointed in 1979. A review is presented of the examination and analysis of the salt contaminants for their identification and of simulation tests to determine their source(s) and mode of formation since 1990. In the analytical campaigns of 1992 and 1994, calclacite (Ca(CH3COO)Cl·5H2O) (ICCD 12-0869) and calcium acetate hemihydrate (Ca(CH3COO)2·0.5H2O) (ICCD 19-0199) were identified with X-ray diffraction and polarized light microscopy and examined with the environmental scanning electron microscope. The various means with which to mitigate the contamination and the crystallization-deliquescence cycles, e.g. consolidation, desalination, and climate control, were also studied. The article focuses on the processes involved in the formation of acetate salt compounds with the publication of the first solubility and deliquescence diagrams of the Ca(CH3COO)2–CaCl2–H2O system at 25°C. Comparisons are drawn with recent work carried out on thecotrichite (Ca3(CH3COO)3Cl(NO3)2·7H2O). The course of action adopted by the conservation staff of the Athenian Agora to combat efflorescence has been termination of cleaning with hydrochloric acid and desalination as a remedial measure in lieu of the costly replacement of wooden cabinets with enameled steel storage cases for the extensive ceramic collection (52,000 catalogued ceramics). Volatile acetic acid concentrations in wooden storage cases in the collection have been found to range from 1039± 20 to 1267 ± 20 μg/m 3 (400 to 500 ppb) at 25°C. Since 1979, all newly excavated ceramics and all ceramics exhibiting efflorescence in the collection have been routinely desalinated. No efflorescence has formed on the desalinated objects. Various methods of mitigation such as controlling the RH are also discussed.
TL;DR: In this paper, real-time interferometry allows the acquisition of sequential high-resolution full-field surface images from hygroscopic materials used in cultural heritage by recording during cycles of changing relative humidity (RH) fluctuations.
Abstract: Due to climate change a slowly increasing annual temperature may be experienced by structures. Relative humidity (RH) fluctuations affect the equiibrium moisture content of materials. Repeated RH cycling leads to mechanical failure and may endanger an object's structural integrity. Preventive conservation is based on adopting measures that will prevent fracture. Real-time interferometry allows the acquisition of sequential high-resolution full-field surface images from hygroscopic materials used in cultural heritage by recording during cycles of changing RH. The differential images allow the development of a preventive methodology directly through surface responses. Indications of the natural onset of degradation can be followed and traced before visible damage occurs, allowing preventive measures to be taken in advance. An ongoing study (Climate for Culture European project (FP7-ENV-2008-1 CfC no. 226973)) aims to experimentally classify structural deterioration as a function of acclimatization and confi...
TL;DR: In this paper, the second harmonic (532 nm) of a Q-switched Nd:YAG laser was used for cleaning while a microwave system emitting at 2.45 GHz was tested for in-depth sterilization.
Abstract: In this work, the potential applications of surface laser removal of biological crusts from Carrara marble artefacts and in-depth microwave selective heating for treatment of possible endolithic growths have been evaluated. The investigations were carried out on seriously deteriorated marble fragments from the monumental tombs of the English Cemetery in Florence, Italy. The second harmonic (532 nm) of a Q-switched Nd:YAG laser was used for cleaning while a microwave system emitting at 2.45 GHz was tested for in-depth sterilization. As is well known, microwaves are strongly absorbed by water via dipolar energy dissipation, which permits selective heating of endolithic organisms. The effects of laser and microwave treatments were characterized using scanning electron microscopy (SEM) along with chlorophyll fluorescence with pulsed amplitude modulated imaging. The latter has allowed the quantification of the impairment effects to photosystem II of epilithic phototrophic organism residues by mapping t...
TL;DR: The final report on the Canadian Conservation Institute's poly(vinyl acetate) and acrylic adhesive research is given after 25-27 years of dark aging and 12-15 years of light aging.
Abstract: The final report on the Canadian Conservation Institute's poly(vinyl acetate) and acrylic adhesive research is given after 25–27 years of dark aging and 12–15 years of light aging. A total of 27 poly(vinyl acetate) and 25 acrylic adhesives were tested for pH, volatile emissions (mostly acetic acid), flexibility, strength, and yellowing after aging. In 1996, the work was first published after three to five years of aging data had accumulated. Measurements for pH, yellowing, strength, and flexibility were recently repeated again and these results are reported here. These new data points are reported to provide insight into the effect of these longer aging periods on the products included in the study. As well, the most stable (according to set criteria) poly(vinyl acetate) and acrylic adhesives tested are revealed, which, except for a few products, do not differ greatly from those reported in 1996.
TL;DR: The basic principles of the peeling test are summarized, some practical approaches and designs that are useful for in situ applications are suggested, and a mathematical procedure suitable for evaluating the results that are obtained is presented.
Abstract: Standard application principles for the peeling test, also known as the scotch tape test, for assessing the surface cohesion characteristics of materials have been presented by the authors in earlier papers on laboratory testing of stone and mortar consolidation effects. The method has been in use for a long time for evaluating the strengthening of surface layers of mortars, but there have been no standards or reliably verified recommendations on how the test should be applied. Nevertheless, the method has been attracting continuing research, because it is a simple and quite reliable method for in situ testing of consolidation effects, if it is applied correctly. Our paper summarizes the basic principles, and presents illustrative results of an investigation of important historic buildings. It goes on to suggest some practical approaches and designs that are useful for in situ applications. We present a mathematical procedure suitable for evaluating the results that are obtained. We recommend repe...
TL;DR: The British Museum has in its collections a magnificent Byzantine ivory panel, which has been connected with two metal pins and adhesive in a previous conservation treatment but there is now concern that these could be having an adverse influence on natural movements within the ivory as discussed by the authors.
Abstract: The British Museum has in its collections a magnificent Byzantine ivory panel. However, the panel has become warped over time and there is a join on the left side, where it has suffered a break in the past. It has been connected with two metal pins and adhesive in a previous conservation treatment but there is now concern that these could be having an adverse influence on natural movements within the ivory. Given the importance of the panel, the decision was made to leave the pins in place and monitor the stability of the panel. As the geometry of the panel is complex, it was felt that microscopic imaging would not be suitable and 3D laser scanning was used instead. This engineering metrology technique is increasingly used in cultural heritage and conservation to record minute three-dimensional changes with high spatial accuracy. The resulting dataset is a detailed metric 3D record of the object surface in-the-round and comparison of subsequent scans with a reference scan can indicate dimensional ...
TL;DR: The use of binding materials in ancient Chinese textiles was widely practiced to enhance both the bond strength and the cohesion between fibers as discussed by the authors, but this problem has not been fully addressed due to the complexity of the binder composition and the limitations of traditional analytical methods.
Abstract: The use of binding materials in ancient Chinese textiles was widely practiced to enhance both the bond strength and the cohesion between fibers. An accurate qualitative assessment of such binding materials is of great significance in heritage research and conservation science: first, to understand the historical development of the textile industry and, second, to choose a suitable conservation method. However, this problem has not been fully addressed due to the complexity of the binder composition and the limitations of traditional analytical methods. This study focused on the use of enzyme-linked immunosorbent assay (ELISA) for the specific identification of proteins in archaeological binder materials. Four ancient Chinese textile binder samples were tested by ELISA. The results showed that all the binder samples reacted positive for ovalbumin, while two printing gold samples reacted negative for collagen-I. This is the first time ELISA has been successfully used to detect protein in ancient Chi...
TL;DR: In 2008, the entire collection was examined, documented, X-ray radiographed, photographed, and conserved by the Carl Nielsen Museum in Odense, Denmark as discussed by the authors, where the authors found that a specific deterioration phenomenon was noticed in the areas where the wax models had been strengthened with internal metal armatures, where a chemical reaction between the wax mixture and the copper containing armature has caused an intense greenish colouring of the wax.
Abstract: The Danish sculptor Anne Marie Carl-Nielsen (1863–1945) often prepared three-dimensional models in wax before producing her works of art. The Carl Nielsen Museum in Odense keeps a unique collection of around 200 of the artist's fragile wax models. In 2008 the entire collection was examined, documented, X-ray radiographed, photographed, and conserved. Analyses of five figurines by attenuated total reflectance-Fourier transform infrared spectroscopy, optical microscopy, and scanning electron microscopy-energy dispersive X-ray spectroscopy showed two different kinds of wax mixtures, one containing beeswax and potato or maize starch as filler, and the other consisting of gypsum, zinc stearate, and a greasy substance. During the examination a specific deterioration phenomenon was noticed in the areas where the wax models had been strengthened with internal metal armatures. A chemical reaction between the wax mixture and the copper containing armature has caused an intense greenish colouring of the wax ...
TL;DR: In this paper, the authors investigated the execution processes and the composition of a set of well-known Florentine copper alloy masterpieces attributed to Donatello: David, San Ludovico, Pulpito della Resurrezione, Capitello, and Amore Attis.
Abstract: We investigated the execution processes and the composition of a set of well-known Florentine copper alloy masterpieces attributed to Donatello: David, San Ludovico, Pulpito della Resurrezione, Capitello, and Amore Attis. Portable laser-induced plasma spectroscopy was used in order to detect the main elements in the alloys and achieve exhaustive compositional maps of the first three works, which were executed through multiple casting and assembling. The compositions of the others were analysed using traditional techniques. The comparison of the results was extended to some celebrated masterpieces by Ghiberti and Brunelleschi, and with the information provided by documentary sources in order to achieve a preliminary picture of the alloys used by Florentine artists during the Early Renaissance.
TL;DR: In this article, laser ablation has been applied for removing overpaint found on the reverse of a signed easel painting by Giacomo Balla, one of the founding members of the Futurist movement.
Abstract: In this work, laser ablation has been applied for removing overpaint found on the reverse of a signed easel painting by Giacomo Balla, one of the founding members of the Futurist movement. After unsuccessful attempts to remove the overpaint layers selectively using organic solvents, a long Q-switched Nd:YAG laser (1064 nm, 120 ns) ablation was successfully trialled, enabling the planning of complete uncovering of a hidden artwork by laser treatment. Laser cleaning was accompanied with a thorough characterisation of the original pigments, binders, and overpaint using Raman and FTIR spectroscopy, along with stratigraphic examination combined with optical and ESEM-EDX analysis. In parallel systematic experimentation on samples simulating the layers to be removed was carried out to interpret the laser removal processes being exploited and fine-tune the treatment.
TL;DR: In this paper, the authors examined whether removal of burial encrustation can be justified in view of its short-term and long-term effects on the substrate, using mock objects.
Abstract: There has been a growing interest in laser cleaning applications for a variety of organic materials such as paper, parchment, textiles, and leather during the last decade. However, archaeological organic materials, notably papyrus, have rarely been investigated. This contribution examines whether removal of burial encrustation can be justified in view of its short-term and long-term effects on the substrate. To examine this, tests using mock objects have been performed. Using artificially soiled and archaeological papyrus samples, optimization of laser cleaning parameters using a picosecond laser (1064 nm, various operating conditions) was attempted. Optimization was based on colorimetry, optical microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, and cellulose degree of polymerization data, both before and after accelerated degradation. In papyrus, there is no clear damage threshold, and substrate degradation can always be observed and is comparable in treated (clea...
TL;DR: In this article, balsa wood samples were impregnated with iron oxides to test extraction treatments, and archeological wood samples are also examined to determine treatment efficiency Electrophoresis and simple immersion treatments were performed using various chemical solutions: a neutral and a conductive substance (potassium nitrate), an acid (acetic acid), acid acid, three alkaline chelating agents (tri-ammonium and tri-sodium citrate and sodium oxalate), three acidic and slightly acidic chelaying agents (ethylenediaminetetraacetic
Abstract: The presence of iron oxides (lepidocrocite, goethite) in archeological wood may result in a degradation of the wood matrix Extraction of these iron oxides is largely dependent on their solubility In this study, balsa wood samples were impregnated with iron oxides to test extraction treatments Additionally, archeological wood samples were also examined to determine treatment efficiency Electrophoresis and simple immersion treatments were performed using various chemical solutions: a neutral and a conductive substance (potassium nitrate), an acid (acetic acid), three alkaline chelating agents (tri-ammonium and tri-sodium citrate and sodium oxalate), three acidic and slightly acidic chelating agents (ethylenediaminetetraacetic acid (EDTA), citric acid, and oxalic acid), and a reductant (sodium dithionite) Potassium nitrate did not extract sufficient amounts of iron, irrespective of whether the treatment was conducted by electrophoresis or simple immersion; any observable dissolution was attribut