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Yayın Chemical and vibrational criteria for identifying early sèvres factory porcelain productions(Multidisciplinary Digital Publishing Institute (MDPI), 2024) Colomban, Philippe; Şimşek Franci, Gülsu; Gerken, Mareike; Gironda, Michele; Mesqui, VivianeThirteen 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.Yayın Non-invasive Raman and XRF study of Mīnā’ī decoration, the first sophisticated painted enamels(Multidisciplinary Digital Publishing Institute (MDPI), 2025) Colomban, Philippe; Şimşek Franci, Gülsu; Ngo, Anh-Tu; Gallet, XavierMīnā’ī wares, crafted during the 12th–13th centuries, represent some of the earliest examples of sophisticated painted enamel decoration by potters. Due to the thinness of these enamel layers, their detailed characterization remains challenging, even with the use of advanced techniques, such as Proton-Induced X-ray Emission (PIXE) analysis and Rutherford Backscattering Spectrometry (RBS). This study provides the first combined non-invasive analysis, using X-ray fluorescence (XRF) and Raman spectroscopy, of five shards attributed to mīnā’ī wares. For comparison, two İznik shards from the 17th century, which feature similarly styled but thicker enamel decorations, were also analyzed. Interestingly, the mīnā’ī paste was found to contain lead and tin, suggesting the use of a lead-rich frit in its composition. This finding was confirmed through micro-destructive analysis, using Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM–EDS). Elements, such as rubidium (Rb), strontium (Sr), yttrium (Y), and zirconium (Zr), produced significant XRF signals and effectively distinguished mīnā’ī wares from İznik wares. A uniform tin-rich glaze, measuring 300–500 µm in thickness, was used as a base layer for the much thinner painted mīnā’ī enamels. The colored areas (blue, turquoise, red, green, black, white, eggplant) revealed the presence of various coloring agents and phases, such as spinels, chromite, and ions like Cu2+ and Co2+, as well as opacifiers like cassiterite and lead–calcium/potassium arsenates. Two distinct cobalt sources were identified: one associated with arsenic and the other with manganese and nickel. These cobalt sources are comparable to those used in İznik pottery. For the first time, boron was detected in the blue enamel of mīnā’ī wares.Yayın Non-invasive rayleigh, raman, and chromium-fluorescence study of phase transitions: β-alumina into γ-alumina ‘Single’ crystal and then to α-alumina(Multidisciplinary Digital Publishing Institute (MDPI), 2025) Redonnet, Juliette; Şimşek-Franci, Gülsu; Colomban, PhilippeIn many advanced materials production processes, the analysis must be non-invasive, rapid, and, if possible, operando. The Raman signal of the various forms of alumina, especially transition alumina, is very weak due to the highly ionic nature of the Al-O bond, which requires long exposure times that are incompatible with monitoring transitions. Here, we explore the use of the fluorescence signal of chromium, a natural impurity in alumina, and the Rayleigh wing to follow the crystallization process up to alpha alumina. To clarify the assignment of the fluorescence components, we compare the transformation of beta alumina single crystals into transition (gamma and theta) alumina and then into alpha alumina with the transformation of optically transparent alumina xerogel and glass, obtained by very slow hydrolysis-polycondensation of aluminum sec-butoxide, into alpha alumina. Vibrational modes are better resolved in thermally treated single crystals than in thermally treated xerogels. Measurements of the Rayleigh wing, the Boson peak, and the fluorescence signal are easier than those of vibrational modes for studying the evolution from amorphous to alpha alumina phases. The fluorescence spectra allow almost instantaneous (<1 s) quantitative control of the phases present.Yayın Non-invasive study of gold nanoparticles in famille rose and ruby-back qing porcelain by luminescence, low-wavenumber raman scattering and pXRF(Multidisciplinary Digital Publishing Institute (MDPI), 2025) Colomban, Philippe; Tang, Hui; Şimşek Franci, GülsuComprehensive studies of Famille rose porcelains, particularly ruby-back pieces, are rare and have generally not addressed the vibrational signatures arising from gold nanoparticles. Due to the high cultural and material value of these artifacts, a strictly non-invasive approach combining X-ray fluorescence (XRF) and Raman (micro-)spectrometry must be employed. If the conservation of porcelain does not pose any difficulties, fakes exist and they must be identified. Preliminary studies show that the presence of metal nanoparticles generates plasmon-related fluorescence. Our results confirm that plasmon fluorescence is more effective than pXRF for detecting colloidal gold, whereas pXRF efficiently identifies associated elements such as arsenic, tin, and, newly observed, antimony; the presence of iron is difficult to demonstrate due to its ubiquitous occurrence. Yellow and green hues, distinct from those produced by Cu2+ ions alone, are mainly due to simple tin yellow (PbSnO3), while the cobalt used originates from a mixture of European smalt (rich in arsenic and potassium) and Asian ores (rich in manganese). Minimal variability was observed among egg-shell porcelains with similar decorations and dimensions, suggesting a common workshop or standardized raw materials and procedures. Two other egg-shell plates employ a different gold preparation technique (addition of Sn and Sb rather than As), which is visually evident in the ruby color.Yayın Phase and composition study of 18th century qallaline tiles, tunis(Multidisciplinary Digital Publishing Institute (MDPI), 2025) Colomban, Philippe; Şimşek Franci, Gülsu; Gallet, Xavier; Ngo, Anh-Tu; Melliti-Chemi, Wided; Ayed, NaceurThe potters of Qallaline (or Kallaline, from qallāl, meaning “potters” in Arabic), a district of Tunis (Tunisia) near the now-vanished Bab Kartâjanna gate, produced tiles from the 16th century until the end of the 19th century, with peak activity in the 18th century. These tiles, made from local clay, feature decorations influenced by Hafsid art, the Castilian Renaissance, the Spanish Baroque of the Valencia region, and Ottoman styles. Their characteristic color palette combines green, blue, and ochre. Representative sherds from various 18th-century sites were analyzed using SEM-EDS, portable XRF (pXRF), and Raman microspectroscopy. The results were compared with tiles from earlier (16th-century Iznik, Türkiye), contemporary (18th-century Tekfur Palace, Istanbul, Türkiye), and later (19th-century Naples, Italy) productions used for similar purposes. The chemical signature of the different cobalt ores used appears to depend primarily on the production period. The pastes used in Iznik, Tekfur, and Qallaline ceramics exhibit different compositions. Qallaline potters employed three types of pastes, varying in calcium content, which were used either separately or together within the same tile. In some cases, tin was also present in association with lead. The cobalts used at Qallaline originate from different sources than those used contemporaneously in Meissen (Saxony), as well as from those used in the decoration of Iznik tiles one or two centuries earlier, which are themselves comparable to the cobalt used in Persian mīnā’ī. The As, Ni, and Mn contents are similar to those of the cobalt employed at the Royal Manufacture of Sèvres, believed to have come from the Giftain Valley in Catalonia.
