Search Results (33)

The restoration of gold leaf on sandstone sculptures requires structural stability, aesthetic considerations, and compliance with the principles of cultural heritage preservation. A primary issue is achieving visual and material compatibility between newly restored and original areas. Based on the “Diagnosis–Analysis–Selection–Restoration” methodology, the research team developed a targeted restoration approach for gilded stone sculptures, using the Shakyamuni sculpture at Erfo Temple in Chongqing as a case study. Assessment of the current situation revealed that over 70% of the sculpture’s surface exhibited gold leaf delamination. The composition and structure of the gold-sizing lacquer, lacquer plaster filler, ground layers, and pigments were investigated using SEM-EDS, XRD, Raman spectroscopy, and THM-Py-GC/MS techniques. The results confirmed that the sculpture featured a typical multilayer gilding structure with clear evidence of historical restorations. Considering both material performance and interfacial compatibility, an NHL2/SiO₂/SF016 composite emulsion and traditional lacquer plaster were selected as the optimal materials for reattachment and infill, respectively. A scientific restoration protocol was developed, encompassing gentle cleaning, targeted reattachment and reinforcement, and region-specific repair methods. Principal Component Analysis (PCA) was used to evaluate the influence of temperature and humidity on the curing behavior of lacquer layers. Additionally, a non-invasive gold leaf color-matching technique was developed by controlling the surface roughness of the gold-sizing lacquer, effectively avoiding the damage caused by traditional color-matching methods. Full article

Multilayer samples are used in a wide range of sectors for their functionality. In the field of cultural heritage, multilayer samples are also common, as in the case of gilded or silvered alloys in the pigment layers in paintings. The X-ray ratios Lα/Lβ, Kα/Kβ, or K/L for an element or for different elements in a multilayer sample depend on the chemical composition and thickness of the superimposed layers and on the chemical composition and thickness of the layer in which the element is situated. Gold decorations of paintings on wood represent examples of multilayered structures and, for this reason, it is important to be able to determine the thickness of the gold layer. In the present paper, gold coatings of several paintings on gilded wood, by Italian artist Taddeo Gaddi (1300–1366 AD), were examined using portable energy-dispersive X-ray fluorescence (ED-XRF) in order to calculate the thickness of the gold layer on ochre by measuring the intensity ratio of the Au-L_α/Fe-K_α X-ray. The experimental results obtained showed that the gold leaves used by the artist have a thickness of approximately 0.3 to 0.4 µm; this also demonstrates the artist’s remarkable ability in creating the gilding. Full article

Thirteen porcelains assigned to Sèvres factory productions and a few references to the other contemporary factories (Chantilly, Limoges, and Venice) have been studied on-site with a portable X-ray fluorescence (pXRF) spectrometer in order to control the provenance attribution. Characteristic XRF signals of major elements (Si, Ca, K, Pb) and minor/trace (Au, Bi, As, Ti, Co, Cu, Zn, Ni, Y, Zr, Rb, and Sr) elements are compared for the paste, blue mark, various glazed (colored) areas, and gilding. The comparison of peak intensities clearly distinguishes different types of hard- and soft-paste porcelain, made from either similar or distinct raw materials. The analysis of transition elements associated with cobalt identifies three types of cobalt blue and reveals that du Barry-style decoration on certain artifacts was typical of 19th-century production. On-site comprehensive studies of the two famous Etruscan-style breast bowls from Rambouillet Castle dairy, using pXRF and Raman spectroscopy, confirm the use of soft-paste porcelain for the cup and hard-paste for its support, providing detailed information on the use of gold nanoparticles in the burgundy-colored decoration. Full article

This study explores the modification of traditional Chinese lacquer by incorporating boiled tung oil (BTO), boiled linseed oil (BLO), and turpentine oil (TO) to enhance its properties for gold leafing applications. Current traditional lacquers are limited by slow drying times and inconsistent surface quality, making their performance suboptimal for decorative gilding. The research addresses these gaps by investigating how varying oil types and concentrations (10%, 30%, and 50%) affect the lacquer’s drying time, viscosity, leveling properties, and overall gilding performance. Results indicate that TO-modified lacquer exhibits the best overall performance, showing the fastest drying time, highest glossiness, and smallest color variation, while BTO provides the smoothest surface and BLO ensures the best adhesion. These results demonstrate that the careful selection of oil type and concentration significantly improves lacquer’s functionality for gold leafing, offering a more efficient and aesthetically superior alternative to unmodified lacquers. This study provides valuable insights for optimizing traditional lacquer formulations for modern applications in gilding and decorative finishes. Full article

To address the challenges posed by the vast and complex knowledge information in cultural heritage design, such as low knowledge retrieval efficiency and limited visualization, this study proposes a method for knowledge extraction and knowledge graph construction based on graph attention neural networks (GAT). Using Tang Dynasty gold and silver artifacts as samples, we establish a joint knowledge extraction model based on GAT. The model employs the BERT pretraining model to encode collected textual knowledge data, conducts sentence dependency analysis, and utilizes GAT to allocate weights among entities, thereby enhancing the identification of target entities and their relationships. Comparative experiments on public datasets demonstrate that this model significantly outperforms baseline models in extraction effectiveness. Finally, the proposed method is applied to the construction of a knowledge graph for Tang Dynasty gold and silver artifacts. Taking the Gilded Musician Pattern Silver Cup as an example, this method provides designers with a visualized and interconnected knowledge collection structure. Full article

To asses the degradation status of the Imperial Doors of the early 19th century Ascension Church iconostasis, a complex study consisting of micro-optical and scanning electron microscopy followed by energy-dispersive X-ray fluorescence and Fourier transform infrared spectroscopy was performed. Accordingly, the entire left door and some small fragments of gilded wood were investigated. The final results evidenced a certain degree of degradation of the lime wood and gilded surfaces, mainly due to the bacterial and fungi attacks given the increased humidity and the presence of more than a century of candle soot. Also, some unsuccessful restorations performed using brass paint instead of gold foils were evidenced. Overall, this study permitted elaborating more appropriate procedures for the iconostasis’ full restoration to its initial form, given that the Ascension Church is classified as a historical objective of national and universal value. Full article

Preserving and restoring architectural monuments of symbolic national significance stand as an unequivocal priority for both local and state authorities. Indeed, with advancements in the technology, materials, and methods of work, there are some specific stages involved in the process of restoring historical buildings; however, maintaining their authentic form and impact poses a serious challenge, necessitating the development of innovative, non-standard technologies and the adaptation of a multifunctional methodology to achieve the desired outcome. The present study focuses on the restoration of the roof covering of the historical building of the “Dormition of the Mother of God” Cathedral in Varna, in terms of technological feasibility and cost-effectiveness. Proposed in this paper is a solution that strives to restore the magnificent roof in adherence to the heritage conservation principles by applying a genuine gold coating instead of retaining the previous dull goldish coating made from alkyd paint, yellow pigment, and gold dust. Through the implementation of descriptive geometry techniques and AutoCAD, followed by verification using Inventor, the study presents a feasible solution for accurately determining the surface area of the domes to be gilded. Full article

Juan Martínez Montañés was one of the most important sculptors and altarpiece architects of the Spanish Golden Age. The restoration of the Santa Clara church in Seville has presented a unique opportunity to study the main altarpiece, crafted by Montañés between 1621 and 1623. He was also in charge of the polychromy and gilding, believing that delegating these procedures to others would diminish the quality of his work. This conviction led to a well-known lawsuit with the renowned contemporary Spanish painter Francisco Pacheco. Ultimately, the painter and sculptor Baltasar Quintero performed the polychromy of this altarpiece, but under the strict conditions of Montañés. Various non-invasive analytical techniques, such as CT, UVF, XRF, and digital microscopy, were employed to study wood treatment and polychromy. Additionally, three samples were prepared as cross-sections and analysed by SEM-EDX. The results revealed Montañés’ meticulous woodwork, anticipating its long-term preservation. Consistent with Montañés’ commitment to maintaining the superior quality of his work, the analysis showed an absence of a ground layer in the flesh areas, while the gilding was executed with high-quality gold. The pigment palette corresponds to the treaties and documents of his time, and the extensive areas of later retouches were accurately located. These new data provide a deeper understanding of both the technique and the high standards of one of the most important and globally recognised sculptors. Full article

This study investigates the practices and rules of Genoese gilding, drawing insights from a 16th-century manuscript containing regulations for gold leaf production. Employing X-ray and ion beam techniques, we quantitatively assess the manuscript’s gold leaf thickness without destructive sampling. Artisanal goldbeater-produced leaves of different thicknesses, applied with a guazzo or mordant technique, served as standards. Further analysis of samples with unknown thickness from the furniture of Palazzo Spinola di Pellicceria in Genoa (Italy) has confirmed the method’s applicability to practical cases. External beam Rutherford backscattering spectrometry (RBS) and particle-induced X-ray emission (PIXE) analyses were carried out using 3 MeV protons at the LABEC accelerator laboratory in Florence. A linear relationship between Gold Lα peak yield and leaf thickness, as measured by RBS, has been established for optimal calibration of portable or hand-held X-Ray fluorescence (XRF) instrumentation for in situ measurements. Moreover, the caratage of the gold foil preserved in the manuscript has been assessed. Full article

This article explores the phenomenon of a specific type of personal adornment worn by members of the Scythian elite in the North Black Sea region in the second half of the 5th century and throughout the 4th century BCE. The discussion juxtaposes the records from 19th-century and early 20th-century excavations with contextual analyses of very recent discoveries from Ukraine, which shed significant new light on the appearance, production, and meaning of Scythian jewelry. The reconstruction of the shape of the jewelry type in question is greatly complicated by two factors: the lack of relevant depictions in the contemporary corpus of Scythian and Greco-Scythian figure scenes and misleading scholarly references to supposed analogies in a Roman-era mosaic, which became the chief reason for the misinterpretations of the ornament’s appearance. Composed of numerous gold or gilded silver tubes; beads; pendants; and, sometimes, “buttons,” this jewelry type is reconstructed in two gender-specific variants in this article: one mesh-like and the other with a cross-chest form. For over a hundred years, scholars have considered only the mesh variant to be the correct reconstruction. As a result, many costume reconstructions of this jewelry form in specialist research and museum displays alike are still proposed without a sufficient evidentiary base. Full article

During the Ming Dynasty, the Five-Dragon Palace functioned as a royal Taoist temple set atop one of China’s holiest Taoist mountains, Wudang Mountain. Two tower polychrome sculptures with exquisite craftsmanship have remained over the centuries. In this study, the painting materials and the techniques used to construct these sculptures were analyzed through multiple characterization methods, including optical microscope (OM) observations, micro-Raman spectroscopy, scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM−EDS), X-ray diffraction (XRD), micro-Fourier-transform infrared spectroscopy (μ−FTIR), and pyrolysis–gas chromatography/mass spectrometry (Py−GC/MS). The results revealed that the pigments used in these sculptures included red pigments, which were composed of mercury (II) sulfide (cinnabar or vermillion), minium (Pb₃O₄), and hematite (Fe₂O₃); green pigments, which included atacamite and botallackite (Cu₂Cl(OH)₃), and blue pigments, which comprised smalt (CoO·nSiO₂) and azurite (Cu₃(CO₃)₂(OH)₂). The white base layer was composed of quartz and mica minerals combined with gypsum or plant fiber, and the gold foil was adhered to the surface using heated tung oil. In addition, a special multi−layer technique was applied, with red under the golden gilding, white under the blue layer, and gray and black under the green layer. Drying oil was used as a binder for lead-containing pigments. This study offers substantial proof of reliable techniques to use in the continuing conservation of these sculptures, and it also serves as a foundation to determine if they can be dated to the late Ming or early Qing Dynasty (17th century). Full article

This article presents the results of a topographical and analytical study using hh-XRF of 22 gold and gilded objects from the Archaeological and Historical Museum of A Coruña (Galicia, Spain). They are highly representative of the northwestern Iberian goldwork from the Chalcolithic (third millennium BC) to the early Roman period (first century AD). This study contributes to our knowledge of the production techniques used in those periods, as well as their evolution over time. The collection includes some of the most representative types in this area, such as Early Bronze Age “sheet collars” and torcs from the Second Iron Age. In the case of torcs, new data are provided on one of the formally best-documented types (the Artabrian type) and on those known as “Baroque torcs” that are characteristic of the final moments of this goldsmith tradition. While pieces from the Chalcolithic and Early Bronze Age were made with alluvial gold, the torcs from the Late Iron Age contain variable amounts of silver and copper. Also detected is the frequent use of cores made of less precious metals, which were subsequently given a golden appearance using gilding techniques. The new data are discussed in light of our current knowledge of NW Iberian goldwork, one of the most representative of this craft tradition in Western Europe for those periods. Full article

The gilded bronze eagles that stand upon the summit of the Tabernacle by Michelozzo in the Abbey of San Miniato al Monte, Florence (Italy) are an exquisite example of Italian Renaissance sculpture. Commissioned by Piero di Cosimo de Medici, the two eagles, representing the ancient Arte di Calimala, were cast and decorated by Maso di Bartolomeo in the 1448–1449 period. A multi-analytical approach was set up to characterize the state of conservation, materials used, and artistic technique of the eagles. Non-invasive methods were used and integrated with micro-invasive analyses, such as X-ray fluorescence (XRF) and Fourier-transform infrared (FTIR) spectroscopy, X-ray diffractometry on powders (XRPD), scanning electron microscopy coupled with EDS (SEM-EDS), and metallographic investigation. The results depict shiny-looking eagles, suggesting the use of oil gilding on almost all surfaces and revealing the presence of polychromies, which is almost unusual in XV-century bronze statuary and is initially hidden by deposits and corrosion products. Indeed, the paws were originally painted with azurite, while the use of cinnabar imparted a vivid red color to the tongue. A black paint containing mercury was found on the eyes and talons. The bales of cloth were decorated with silver, which is now almost completely lost and whose remains are not visible due to being tarnished, while fine details in gold were detected on the lanyard. Full article

The study concerned a diagnostic spectroscopic campaign carried out on the panel painting depicting the Coronation of the Virgin (first half of the 15th century) by the late-Gothic Italian painter Michele di Matteo. The main aims were the identification of the original painting materials and the characterization of the painter’s artistic technique. A combined approach based on non- and micro-invasive techniques was employed. Visible and ultraviolet-induced fluorescence photography was used to select the areas of interest for spectroscopic analyses; X-ray radiography assessed the state of conservation of the support, while X-ray fluorescence and external reflection Fourier transform infrared spectroscopies allowed the chemical identification of pigments, binders, and varnishes. Attenuated total reflection infrared spectroscopy, optical microscopy, and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy were used to visualize and characterize the materials in the pictorial layers. The results highlighted the presence of pigments, possibly applied with an egg binder, consistent with the period of the production of the painting, as well as modern pigments used during subsequent restorations: an imprimitura with lead white and a gypsum-based ground layer. Concerning the gilding, the guazzo technique was confirmed by identifying a red bolo substrate and gold leaf. Full article

The subjects of this research are the burial clothes of Polish King Sigismund III Vasa and his wife Constance, which were woven and embroidered with silk and metal threads. Fragments of the textiles underwent spectroscopic, spectrometric, and thermogravimetric analyses. The hydrofluoric acid extraction method was improved to isolate various classes of dyes from the textile samples that had direct contact with human remains. High-performance liquid chromatography, coupled with diode array and tandem mass spectrometry detectors with electrospray ionization (HPLC-DAD-ESI-MS/MS) facilitated the detection and identification of colorants present in the textiles. Cochineal, indigo-, madder-, orchil-, and tannin-producing plants were identified as the sources of dyes used. Scanning electron microscopy with an energy-dispersive X-ray detector (SEM-EDS) was employed to identify and characterize the silk fibers and mordants and the metal threads. The presence of iron, aluminum, sodium, and calcium in the silk threads suggests their potential use as mordants. The analysis of the metal threads revealed that most of them were made from flattened gilded silver wire, with only a few being cut from a sheet of metal. Typical degradation mechanisms of metal threads were shown, resulting from both burial environment and earlier manufacturing process, and the use of the textiles in clothing, i.e., a significant loss of the gold layer was observed in most of silver gilt threads, caused by abrasion and delamination. The results of the thermal analysis confirmed the presence of silk and silver threads in the examined textiles. Full article