Pagán is an ancient city located in Myanmar that is renowned for the remains of about 4000 pagodas, stupas, temples and monasteries dating from the 11th to 13th centuries. Due to a magnitude 6.8 earthquake in 2016, more than 300 ancient buildings were seriously damaged. As a part of the post-earthquake emergency program, a diagnostic pilot project was carried out on Me-taw-ya temple wall paintings to acquire further information on the materials and on their state of conservation. This article presents our attempts at characterising the painting materials at Me-taw-ya temple using non-invasive portable energy dispersive X-ray fluorescence (ED-XRF), portable Raman spectroscopy and micro-invasive attenuated total reflectance—Fourier transform infrared spectroscopy (ATR-FTIR), micro-Raman spectroscopy (µ-Raman), gas chromatography-mass spectrometry (GC-MS), polarized light microscopy (PLM) and environmental scanning electron microscope—X-ray energy dispersive system (ESEM-EDS) investigations with the aim of identifying the composition of organic binders and pigments. The presence of a proteinaceous glue mixed with the lime-based plaster was ascertained and identified by GC-MS. In addition, this technique confirmed the occurrence of plant-derived gums as binders pointing to the a secco technique. Fe-based compounds, vermillion, carbon black and As-compounds were identified to have been incorporated in the palette of the murals.
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.
After a huge non-invasive diagnostic campaign performed on the corpus of Giovanni Santi’s artworks, three paintings were selected and investigated: the Martyrdom of Saint Sebastian panel, the Visitation altarpiece and the canvas with Tobias and the Archangel Raphael (c. 1487 and 1494). Micro-invasive investigations including optical microscopy, ESEM-EDX, micro-Raman spectroscopy, FTIR and FTIR-ATR spectroscopy and GC-MS were carried out on selected micro samples. The results of the integrated analyses confirmed the use of a Renaissance palette with oil and, only in a few cases, tempera techniques. Some significant peculiarities emerged in Santi’s practice, as he used localized off-white priming and colorless powdered glass with a siccative oil—in red, flesh, pinkish and green hues—confirming the influence of the Flemish painters in Urbino and, possibly, also in western central Italy. This innovative technical expedient compared to the traditional Italian painting technique was identified also in red and bluish samples collected from the Communion of the Apostles panel painted by Justus of Ghent around 1473–1474 for Urbino Corpus Domini Confraternity. The Flemish master was called to the court of Duke Federico to paint in oil and his presence at the ‘Urbino workshop’ probably contributed to the diffusion of this technique. Both in Giovanni Santi’s paintings and the Communion of the Apostles, the glass particles are related to a soda-lime glass typical of the Italian area, widely detected in Italian paintings from the late 15th and 16th centuries.
Diagnostic investigations were carried out on a rare Chinese polychrome glazed ceramic dating back to the reign of the Xuande Emperor (1426–1435). The double-walled warming bowl was investigated using several non-invasive methods such as portable optical microscopy, endoscopy, portable X-ray fluorescence spectrometry, X-radiography, and computed tomography. One microsample was collected and analyzed by scanning electron microscopy with an energy dispersive X-ray detector. According to the results, the chemical composition of the paste suggested a porcelain typology, while the glaze belongs to the lead–barium–silicate (PbO-BaO-ZnO-SiO2) system. These unexpected data contrast with common knowledge, which attests that the addition of barium in glass and ceramics manufacturing disappeared soon after the Han dynasty (206 BCE-220 CE). Moreover, the combination of PbO-BaO-ZnO-SiO2 seems to be quite rare both in ancient pre-Han times and during the Ming and Qing dynasties. This paper aims to demonstrate that (a) the use of barium for glaze and glass composition, which seems to have its roots in Taoist alchemy, was not totally halted in later periods compared to the Han dynasty; (b) lead–barium–zinc–silicate glaze was used during the Xuande Emperor’s reign. Through a review of ancient Chinese literary sources, we found a lot of unpublished information on the use of barium, lead, and zinc in the production of glazed ceramics during this period. The polychrome glazed warming bowl suggests a particular production that flourished during the brief reign of the Xuande Emperor.
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.