Element determination in medieval soil samples by total reflection X-ray fluorescence analysis

An aqua regia extraction procedure for heavy metals in soils optimised for total reflection X-ray fluorescence analysis is presented. The procedure is applied to 92 soil samples of medieval layers from the city area of Dortmund. Sixteen elements (P, S, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Rb, Sr, Ag, Sn, and Pb) were used to characterise 17 sample sites. The results are projected onto the medieval urban structure of Dortmund. Two sites loaded with non-ferrous heavy metal could be detected and correlated with archaeological data. The efficiency and repeatability of the proposed extraction procedure is discussed.     

An archaeometric approach about the study of medieval glass from Siponto (Foggia, Italy)

Medieval glasses, including feet and rims of chalices, fragments of lamps and globular bottles, coming from the archaeological site of Siponto (Foggia, Italy), were analyzed by Inductively Coupled Plasma Emission Spectroscopy and Graphite Furnace Atomic Absorption Spectroscopy for investigating and defining glass production technology in Apulia (Italy) in the Middle Ages, because of the poor understanding currently achieved on either compositional and technological features of medieval glass items. The examined finds, whether colourless or coloured blue, yellow-green, yellow, pink and red, revealed a typical silica-soda-lime-composition. The chemical analysis and the statistical treatment of data allowed to trace former, flux, modifier and, where it is present, the element responsible for colour, clarifying production technology issues. It has been possible to identify, moreover, objects obtained by recycling of cullets or finished items.Finally, this work evaluates the effectiveness of the statistical multivariate treatment by Principal Component Analysis (PCA), Clustering Analysis (CA) and Factor Analysis (FA) on compositional data to obtain technological information in opposition to the conventional binary oxides diagram, which represent the most common, widely assessed, archaeometrical practice to obtain technological information from compositional data.     

A combined analytical approach applied to Medieval wall paintings from Puglia (Italy): The study of painting techniques and its conservation state

A combined analytical approach has been applied to the wall paintings, dated from 10th to 14th centuries, of the Santi Stefani crypt at Vaste (Lecce, Southern Italy). These paintings are a precious testimony of Medieval art in Southern Italy. However, the church shows problems of damp as well as clear evidences of flora, fungi and mold presence, and there is little knowledge of the pictorial methodologies used. Raman spectroscopy allowed to determine the palette and to reconstruct the worksite and the chronological sequence of the various paint layers. Kaolinite, calcite, carbon black, hematite, massicot, goethite, indigo and azurite were identified as pigments along with synthetic pigments, like phthalocyanine blue and chrome yellow. Attenuated total reflectance‐Fourier transform infrared spectroscopy suggested the presence of egg as a binder in some pictorial layers. The conservation state of the crypt is poor, and detachments of pigmented layers are frequent because of the presence of subflorescence and efflorescence: nitrate, sulfate and chloride salts have been identified spectroscopically and quantified by ion chromatography. The extensive use of kaolinite in Santi Stefani, actually not uncommon in Medieval art, is observed for the first time in a crypt of Puglia: its use to stabilize some pigments and to improve their adhesion on substrate is proposed. Copyright © 2015 John Wiley & Sons, Ltd.     

Matisse to Picasso: a compositional study of modern bronze sculptures

Inductively coupled plasma-optical emission spectroscopy (ICP-OES) was used to determine the bulk metal elemental composition of 62 modern bronze sculptures cast in Paris in the first half of the twentieth century from the collections of The Art Institute of Chicago and the Philadelphia Museum of Art. As a result, a comprehensive survey of the alloy composition of the sculptures of many prominent European artists of the early twentieth century is presented here for the first time. The sculptures in this study consist of predominantly copper with two main alloying elements (zinc and tin). By plotting the concentrations of these two elements (zinc and tin) against each other for all the sculptures studied, three clusters of data become apparent: (A) high-zinc brass; (B) low-zinc brass; (C) tin bronze. These clusters correlate to specific foundries, which used specific casting methods (sand or lost wax) that were influenced by individual preferences and technical skills of the foundry masters. For instance, the high-zinc brass alloys (with the highest levels of tin and zinc and the lowest melting temperature) correspond to most of the Picasso sculptures, correlate with the Valsuani foundry, and are associated with the most recent sculptures (post-WWII) and with the lost-wax casting method. By expanding the ICP-OES database of objects studied, these material correlations may become useful for identifying, dating, or possibly even authenticating other bronzes that do not bear foundry marks. Figure   Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.

Portable Raman study on the conservation state of four CorTen steel‐based sculptures by Eduardo Chillida impacted by urban atmospheres

Weathering steel, and particularly CorTen steel, is a very used material for modern artworks exhibited outdoors. One of the characteristic that makes this material so attractive to artists is the property to develop a protective rust layer composed by iron oxides which preserves its metallic core from atmospheric corrosion. This study was conducted to evaluate the conservation state of four CorTen sculptures by Eduardo Chillida, located in different places of Bilbao city (north of Spain) and affected by different factors (environmental among others) by using Raman spectroscopy. Measurements were performed in situ with a handheld Raman spectrometer mounted on a tripod with x–y–z axes motorization at the micron level. The most common oxyhydroxides detected were lepidocrocite (γ‐FeO(OH)), goethite (α‐FeO(OH)), hematite ( ‐Fe₂O₃) and magnetite (Fe₃O₄), being goethite the most stable phase. All the iron oxyhydroxides were identified in all of the studied sculptures but their relative amounts were different for each sculpture. The consequences of the marine aerosols exposure in the steel surface were also studied, detecting limonite (FeO(OH)·nH₂O) and akaganeite (β‐FeO(OH)). The results confirmed that the evolution of the rust layer present on the analyzed weathering steels is different, depending both on the exposure and the particular type of the steel. Copyright © 2012 John Wiley & Sons, Ltd.     

聚丙烯酸酯－环氧树脂IPN乳液的合成

研究摩岩石刻保护材料聚丙烯酸酯-环氧树脂互穿聚合物网络乳液的合成,讨论影响凝聚率,乳液稳定性和乳液胶膜耐水性、吸水率的因素,得到最佳工艺条件。     

The infrared microspectroscopic and energy dispersive X-ray analysis of paints removed from a painted, medieval sculpture of Saint Wolfgang

A spectroscopic study of paints removed from a 15th century sculpture depicting Saint Wolfgang, which is housed in the Ball State Museum of Art, was performed. Infrared spectra on the minute paint samples were obtained using a microscope accessory in the transmission mode, and the spectra were compared to reference spectra of known art pigments and materials. In addition, energy dispersive X-ray spectra were obtained using a scanning electron microscope source. Although many of the pigments found are relatively modern pigments, the first application of paint is composed of materials consistent with the sculpture's medieval date. Pigments identified include brass gilding, calcium carbonate, China clay, lac dye, orpiment, Prussian blue, satin ochre, ultramarine blue and red, and zinc chromate. A zinc tungate finish was also identified.     

开平碉楼灰雕和壁画颜料碎片原材料的拉曼光谱分析

本文采用显微激光拉曼光谱分析了开平碉楼灰雕和壁画黄色颜料碎片的原材料组成,通过分析发现:灰雕的主要成分是稻草杆(作为骨架材料),石灰(CaCO3),沙(石英SiO2)以及黄色颜料类胡萝卜素.壁画黄色颜料碎片的成分则是针铁矿(α-FeOOH)和CaSO4.这也说明开平碉楼在选材上,即使是在同一栋楼内,相同颜色的颜料使用的...     

Sculpture Inspired by Alfred Gray

Ispired by a decade of mathematical collaboration with Alfred Gray, the sculptor Helaman Ferguson describes his series of negative curvature sculptures, all triply punctured tori. These sculpturesare in bronze, marble, and granite. Five photographs are included of a 12 foot high 20 ton snow approximation to a Costa minimal surface which dramatically survived a heat wave due to its negative curvature.