Search Results (31)

Ten ukiyo-e woodblock prints from the collection of the Museo delle Culture in Lugano (Switzerland) were analyzed to identify the materials used in their production. These Japanese artworks were traditionally created with colors derived from minerals and plants, mixed with diluted animal glue and applied to paper using wooden matrices. Due to their fragility, non-invasive external reflection infrared spectroscopy and imaging analysis were employed. Spectral data were compared with reference samples of Japanese pigments and existing literature, reflecting the growing interest in the characterization of ukiyo-e prints. Within the limits of the non-invasive approach, several colorants were identified, including akane (madder), suo (sappanwood), yamahaji (Japanese sumac), kariyasu (Eulalia), and kio (orpiment), along with a proteinaceous binding medium. The extensive use of bero-ai (Prussian blue), applied both as a pure pigment and in mixtures, was confirmed. Notably, mica was detected in the background of one print, providing the first analytical evidence of the kirazuri decorative technique, which produces a sparkling, silver-like effect. Ultraviolet-induced fluorescence imaging further contributed to the assessment of conservation status, revealing faded decorative motifs and signs of previous water damage. Full article

Orpiment (As₂S₃), a yellow mineral pigment widely used in historical artworks, undergoes degradation that seriously threatens the integrity of Dunhuang murals. Reactive oxygen species (ROS) exist widely in air, which may be one reason for the color change of pigments. This study aims to investigate the degradation effects and mechanisms of four ROS—hydroxyl radical (·OH), singlet oxygen (¹O₂), peroxynitrite anion (ONOO⁻), and hydrogen peroxide (H₂O₂)—on orpiment. By simulating chemical reaction systems, the interaction processes between different ROS and orpiment were qualitatively and quantitatively analyzed, and the degradation capacities of each ROS on orpiment were evaluated. The experiments show that all ROS can induce orpiment degradation, among which ·OH exhibits the strongest degradation capacity due to its high oxidation potential, while ¹O₂, ONOO⁻, and H₂O₂ have relatively minor impacts on orpiment aging. It is the first time that a study has confirmed that ROS (especially ·OH) may drive orpiment degradation in environments, contributing to the increasing number of conservation strategies for artworks. Full article

The Matra As–Sb deposit (Alpine Corsica, France) is hosted in the normal N–S trending Matra Fault. Sulfide minerals in ore consist of realgar, stibnite, and pyrite with minor orpiment and hörnesite. The gangue includes quartz, dolomite, and calcite. In this study, the microstructural analysis of selected ore samples has been combined with the geochemical characterization of the sulfides. The results depict a succession of events that record the evolution of the ore deposit related to fault movement. In the pre–ore stage, plumose, crustiform, jigsaw, and feathery textures of quartz testify to a short–lived boiling event. The mineral assemblage of the main–ore stage includes an Fe(–Zn) substage dominated by the formation of different textures of pyrite. In general, pyrite samples contain significant concentrations of As (≤32,231 ppm) and Sb (≤10,684 ppm), with lesser amounts of by Tl (≤1257 ppm) and Ni (≤174 ppm). This is followed by an Sb–As–Fe substage of pyrite–stibnite–realgar ±orpiment. The precipitation of the sulfides was mainly driven by changes in ƒS₂. The increasing level of oxidation is attributed to a progressive influx of meteoric water resulting from reactivation of the Matra Fault. Full article

The existence of historical pigments databases is important to speed up cultural heritage research. Knowledge of their chemical composition and their manufacture contributes to the study of art history and helps develop accurate conservation-restoration strategies. In this study, a total of nineteen pigments, among which we find silicates (Egyptian blue, natural and synthetic blue ultramarine, green earth and chrysocolla), oxides (natural and synthetic hematite, red and yellow natural ochres, and chromium green), carbonates (natural and synthetic azurite, natural and synthetic malachite, and white lead), sulphides (natural and synthetic cinnabar, and orpiment) and acetates, (verdigris) have been characterized by Fourier Transform Infrared-Spectroscopy in Attenuated Total Reflection (ATR-FTIR) and Diffuse Reflectance (DRIFT) modalities. Considering the latter, there is still a great deal of uncertainty in the interpretation of the different IR vibrational bands. Therefore, a comparative study between these two techniques has been carried out to highlight the potential of DRIFT spectroscopy as a portable and non-destructive technique that allows the differentiation and characterization of historical pigments in the field of cultural heritage. Before performing FTIR analysis, pigments were analysed using X-ray diffraction (XRD) to detect impurities and/or additives in the pigments. Differentiation between natural and synthetic pigments was possible due to the identification of impurities in natural pigments, and manufacture-related compounds or additives in synthetic pigments. Results obtained in this study have proven DRIFT to be a very useful analytical technique for in situ characterization of heritage materials. This study serves as an initial step in clarifying the challenges and uncertainties associated with interpreting spectra obtained through the DRIFT modality. However, the use of other complementary analytical techniques is required. Full article

Choirbooks are historical heritage manuscripts used for the performance of vocal music in religious ceremonies in colonial times. This study aimed to understand the characteristics of choirbook manuscripts produced in the Real Audiencia de Quito during the 17th century. The methodology combined non-invasive techniques, such as infrared false-color imaging (IRFC) and X-ray fluorescence (XRF), together with spot analysis by scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) and Fourier transform infrared spectroscopy with attenuated total reflection (FTIR-ATR). The analytical results revealed the use of pumice, chalk and lime carbonate as support materials in the manufacturing process and surface treatment of the parchment. In the illuminations, three pictorial techniques based on protein, polysaccharide and lipid binders were recognized, establishing that the pigments used with greater regularity in the illuminations were vermilion, minium, verdigris, orpiment, azurite, and indigo, preferably in a pure state. Materials used less regularly were also identified, such as yellow ochre, saffron, smalt, red ochre, and bone black, among others. Regarding the vulnerability of the pictorial materials, it was determined that, although most of the pigments exhibit chemical stability, they present some vulnerabilities associated with their intrinsic composition and the medium that contains them. Full article

This study investigates the materials and techniques used in three Mexican platters, or bateas, from the Victoria and Albert Museum collection. Our analytical approach included the use of non-invasive techniques, such as infrared reflectography, scanning X-ray fluorescence, and digital microscopy, which informed limited but targeted sampling. Traditional pigments were identified, including indigo, carbon black, red lead, lead white, and orpiment, and materials such as dolomite, gypsum, ochres, and clay were also found. A red organic dye was seen but could not be identified. The stratigraphy of the objects was also investigated. The condition of the objects was also evaluated, and the results will be used to inform future conservation decisions. The findings add to the published knowledge of the materials and techniques of early colonial Mexican objects and can be of use in future investigations, facilitating exchanges and collaborations focused on this type of objects, which are rare in UK collections. Full article

This paper presents the preliminary results of an investigation on the unexplored topic of polychromy on provincial stone sculptures from the Roman provinces in Germania through the innovative application of heritage materials science techniques. A group of three life-sized statues dating to the 1st Century CE recovered from Ingelheim, near Mainz, retains remarkably well-preserved traces of pigments. These are ripe for emerging non-invasive technologies supplemented by micro-sampling to validate results and provide information relating to mixing and layering not available to the naked eye. The most strikingly visible areas of extant polychromy were retained on the sculpture of a young woman, reported on here as the first phase of this programme of research. The results suggest that the statue was originally covered in a gypsum layer before the application of complex and diverse recipes of pigment applied as mixtures and in layers to create required hues and shadowing on sculpted features. The palette includes ochres and green earth mixed with small amounts of minium (red lead), realgar and lapis lazuli (ultramarine blue) added to create skin tones, and a vibrant blue-green tunic created from Egyptian blue, bone black, ochres, cinnabar and green earth; the palla and peplos contained ochres, bone black, and orpiment, and mixes of these created the detail of coloured jewellery. Of great interest was the detection of bone black on many features, particularly as a shading agent to enhance sculpted features, such as folds in cloth, providing a more realistic and flowing articulation. This is a revolutionary observation that provides previously unexplored insights into artistic polychromic practice in Antiquity. Full article

This pioneering work studied the medieval color palette of four manuscripts produced in the scriptorium of Alfonso X, king of the Crown of Castile (r. 1252-84), including the Songs of Holy Mary (Cantigas de Santa Maria, in Rich Codex and Musicians’ Codex), Lapidary (Lapidario), and Book of Games (Libro de los juegos). Scientific analysis based on fiber-optics reflectance spectroscopy in the visible and Raman spectroscopy showed a color palette based on lapis lazuli, indigo, azurite, vermilion, red lead, orpiment, yellow ochre, two different greens (bottle green and vergaut), lead white, carbon-based black, and most importantly, brazilwood pinks, reds, and purples. So, it is now the first reported use of this lake pigment in European medieval manuscript illumination. The painting technique is also discussed. The diversity of colors and techniques, with the presence of lapis lazuli, brazilwood lake pigments, purple, and gold, demonstrates Alfonso X’s desire to produce sumptuous manuscripts. Full article

The Nanpanjiang basin hosts the world’s second-largest concentration of Carlin-type gold deposits. To decipher the origin and evolution of hydrothermal fluid, this study conducted Sm–Nd dating, in-situ trace element, and C-O-Sr isotopic analyses on three types of calcite samples from the giant Lannigou gold deposit in the Nanpanjiang basin, SW China. The type-I calcite, intergrown with Au-bearing arsenian pyrite, has an Sm–Nd isochron age of 213 ± 7 Ma (MSWD = 0.81), indicating that gold mineralization occurred in Late Triassic. The type-II calcite, which coexists with high-maturity bitumens and cut through the main-stage gold orebodies, yields an Sm–Nd age of 188 ± 14 Ma (MSWD = 0.34), representing a post-ore hydrocarbon accumulation event. The type-I and type-II calcite samples have low REE contents (5.28–51.6 ppm) and exhibit MREE-enriched and LREE-/HREE-depleted patterns. Combined with their identical C-O-Sr isotopes, we suggest that hydrothermal fluids responsible for the precipitation of type-I and type-II calcite samples were derived from a mixed metamorphic fluid and meteoric water source. In contrast, the type-III calcite samples, associated with realgar and orpiment, have distinct Mn, Sr, and As contents, REE patterns, and C-O-Sr isotopic composition from the type-I and II calcites, suggestive of different fluid sources. Based on our and previously published data, we propose that the fluid evolution, gold mineralization, and hydrocarbon accumulation in the Nanpanjiang basin are closely related to the Indosinian and Yanshanian orogenies in South China. Full article

S- and Se-based chalcogenide glasses are intrinsically metastable and exhibit a number of photo-induced effects unique to this class of materials, reversible photostructural changes and photo-induced anisotropy being major examples. These effects are usually interpreted in terms of the formation of valence alternation pairs and ‘wrong’ bonds. In this work, using density functional theory simulations, we demonstrate for the case example of ${\mathrm{As}}_2{\mathrm{S}}_3$ that a strong decrease in the optical band gap can be achieved if a polymorphic transformation of the local structure from orpiment to that of tetradymite takes place. For the formation of the latter, the presence of lone-pair electrons in near-linear atomic configurations is crucial. Our results represent a novel approach to understanding the photo-induced structural changes in chalcogenide glasses as being due to the presence of polymorphism, and will lead to their wider use in various photonic devices. Full article

The Virgin Hodegetria, located in the Cathedral of Santa Maria Nuova in Monreale, near Palermo (Italy), probably dating the first half of the 13th century, is one of the earliest examples of medieval panel painting in Sicily. A diagnostic campaign was carried out on the panel aiming to identify the constituting materials and the executive technique, as well as to assess the state of conservation for supporting the methodological choice of the restoration intervention. Both non-invasive (X-ray radiography, digital microscope, multispectral imaging, ED-X-ray fluorescence) and micro-invasive (polarised light microscopy, ESEM-EDX, ATR-FTIR spectroscopy and micro-Raman spectroscopy) analyses were performed. According to the results, the executive technique followed the 13th–14th-century Italian painting tradition. A complex structure was applied on the wooden support, consisting of a double layer of canvas and several ground layers of gypsum and glue-based binder. The underdrawing was made by a brush using carbonaceous black pigment. The original palette includes red ochre, red lead, azurite, carbon black and bone black. During the several restorations, mercury-based red, indigo, smalt blue, orpiment and synthetic mars were used. The original silver leaf of the frame was covered with red tin-based lake and subsequently regilded with gold leaf. Proteinaceous and oil binders were also detected. Full article

Roman glass is well studied and known to have been produced from a mineral soda source and calcareous sand with variation between elements relating to naturally occurring minerals in the sands. While the common characteristics of colourants and opacifiers used in opaque and translucent glasses are well understood, the diverse elemental composition of colouring agents associated with the highly specialised, and largely unexplored, technique of enamel-painted glass has never been firmly established. There remains a significant gap in knowledge of pigments used for this technological innovation which is here addressed through the deployment of non-invasive portable X-ray Flourescence (pXRF) analysis and microphotography on a unique Roman enamel-painted gladiator glass from Vindolanda fort. This vanguard research has successfully established, for the first time, a palette of pigments associated with this specialist technique. It is now possible to unravel previously unknown information on complex manufacturing processes and significantly expand the repertoire of the pigments bound up in enamelling recipes used to depict the striking iconographic scenes on the Vindolanda vessel and, potentially, other Roman enamelled glassware. The detection of Cinnabar, Egyptian blue, Orpiment and other pigments are ground-breaking discoveries that will have a transformative impact on early glassmaking studies and push the boundaries of scholarship into new directions of analytical approaches in heritage materials science to complement recent success in this field with Raman spectroscopy and other techniques. The methodology is unprecedented and has been validated through the high quality of the resulting data which permits the extrapolation of elemental compositions of enamelling materials from those associated with the base vessel. This unique approach provides remarkable insights that will revolutionise our understanding of enamelling technologies using the Vindolanda vessel as the investigative platform for forgotten practice. Full article

The illuminated manuscripts at the Gulbenkian Museum were produced in the 17th century, in scriptoria of the Armenian diaspora. In this work, we selected analytical methods that can be used in situ to study the colors of the illuminations. Scientific analysis based on fiber-optics reflectance spectroscopy in the visible and Raman spectroscopy has shown the use of a medieval palette based on inorganic pigments such as lapis lazuli, minium, vermilion, orpiment, indigo, two different greens (vergaut and malachite), lead white and carbon black. More importantly, in this context, it showed that the very important reds and pinks are possibly based on carminic acid. The painting technique is, however, different, as are the ways of painting the faces, hands, and vestments. The range of colors in the Bible and the three Gospel Books, enhanced by lapis lazuli blue and organic reds and pinks, demonstrates a desire to create exceptional illuminated manuscripts. Full article

The most important painter from Urbino in the last decades of the 15th century (1439 ab.–1494) was Giovanni Santi, the father of Raphael. The lack of scientific literature about Santi’s practice and the possible peculiar role of Urbino in the development of painting techniques in northern Italy suggested in-depth investigations of the entire corpus of his paintings. A well-established sequence of multispectral imaging, spectroscopic and microscopic investigations was performed on 24 wood panel paintings and 2 canvases attributed by most scholars to Giovanni Santi (1439 ab.–1494) to collect a large set of significant data. This systematic research allowed his painting technique to be defined, starting from the type of supports he used and from the features of the underdrawing, which quite frequently included characteristic regular hatching. The pigments used were widely investigated by means of ED-XRF and reflectance spectroscopy (vis-RS); a meaningful multivariate statistical method (PCA and HCA analysis) was also applied to the ED-XRF dataset acquired for representative hues. In particular, the vis-RS technique proved to be a simple and effective diagnostic tool to detect many pigments, including indigo, and to distinguish between two different types of red lakes, avoiding sampling and more complex analyses. Santi used lead white, Fe-Mn-based pigments, vermilion, red lake, natural blue ultramarine, azurite, copper-based green pigments (particularly verdigris), lead-tin yellow, scarcely ever orpiment and, in a few green mixtures, also indigo. Despite the palette being linked to tradition, the master appeared to introduce some peculiarities, such as the addition of glass powder, and mixing pigments both in a traditional way and using them to create chromatic effects unusual for his time. This research confirmed that the systematic use of the integrated non-invasive methods is highly representative, and the results of this wide diagnostic campaign provided a significant dataset which allowed the implementation of a scientific database related to central Italy Renaissance paintings and materials. Full article

Microbes have important impacts on the mobilization of arsenic in groundwater. To study the effects of sulfide on As(V) bioreduction in sulfidic groundwater, Citrobacter sp. JH012-1 isolated from sediments in the Jianghan Plain was used in a microcosm experiment. The results showed that sulfide significantly enhanced As(V) bioreduction as an additional electron donor. The reduction rates of As(V) were 21.8%, 34.5%, 73.6% and 85.9% under 0, 15, 75 and 150 µM sulfide inputting, respectively. The main products of As(V) bioreduction were thioarsenite and orpiment and the concentration of thioarsenite reached to 5.5 and 7.1 µM in the solution with the initial 75 and 150 µM sulfide, respectively. However, under 0 and 15 µM sulfide inputting, the dominant product was arsenite with no thioarsenite accumulation. The decrease in pH enhanced the bioreduction of As(V) and promoted the formation of thioarsenite and orpiment. In addition, the percentage of thioarsenite in total arsenic decreased with the decrease in the ratio of sulfur to arsenic, indicating that the formation of thioarsenite was limited by the concentration of initial sulfide. Therefore, the presence of sulfide had a significant effect on the transformation of arsenic in groundwater. This study provides new insights into the bioreduction of As(V) and the formation of thioarsenite in sulfidic groundwater. Full article