A note on glass and silica in oil paintings from the 15th to the 17th century

This articles reports new discoveries relating to ground glass and silica in European easel paintings from the 15th to the 17th centuries that were created by various German, Italian and Netherlandish artists. The earliest known additions of these extenders date to the early 1430s. Glass powder of varying fineness, prepared from vessel or window cullet, is often found in red lake glazes as well as in other colours or preparatory layers of paintings. SEM/EDX analyses of the glass particles reveal a variety of chemical compositions (soda ash, wood ash, wood ash-lime, wood ash-lead, mixed alkali), which are discussed with respect to the provenance of the paintings. Historical sources on painting techniques mention glass additions most frequently to accelerate drying of oil paints, but also occasionally to facilitate grinding of pigments. Another possible function of powdered glass and silica, especially in oil-bound red lake glazes, is that of a transparent filler, as will be here discussed based on paint trials.     

Consolidation and protection by nanolime: Recent advances for the conservation of the graffiti,Carceri dello Steri Palermo and of the 18th century lunettes,SS. Giuda e Simone Cloister,Corniola (Empoli)

Nanolime dispersed in 2-propanol was extensively used for the consolidation of wall paintings. The knowledge of the advances of this methodology dealing with all the possible effects associated with the nanolime new material in conservation is fundamental to assess and improve the technique. In this paper, four different dispersions of Ca(OH)₂ nanoparticles were characterised by Small Angle X-rays Scattering technique (SAXS) and Transmission Electron Microscopy (TEM) in order to achieve information on size, shape, polydispersity, agglomeration, and crystal structure (by SAED patterns) of the particles. Once characterised, the dispersions were tested in two different case studies, the Carceri dello Steri in Palermo with their graffiti and the 18th century lunettes at the SS. Giuda e Simone Cloister, Corniola (Empoli) with their lime-based mural paintings. The treated samples were characterised in relationship to either their morphology and surface chemical composition by Scanning Electron Microscopy coupled with Energy Dispersive X-rays spectroscopy (SEM-EDX), or their water absorption and mechanical properties (resistance to material abrasion). The results obtained showed that all the dispersions were nanometrically structured and their application succeeded in recovering the mechanical properties of the painting or graffito layers, not altering their permeability to water and keeping perfectly the wall transpiration. However, the dispersions constituted of the nanoparticles obtained via a synthesis able to control size and shape of the Ca(OH)₂ particles resulted in a better performance in situ, even if the differences found by SAXS and TEM were slight.     

Detection of diagenetic alterations by Spectroscopic Analysis on Archaeological Bones from the Necropolis of Poseidonia (Paestum): A case study

Understanding the chemical and physical alteration in archaeological bones, occurred after burial, is very interesting for researchers. In this paper, we present a study on the diagenetic alteration of human archaeological bony tissues from Paestum (South Italy), by combining complementary spectroscopic techniques, such as solid-state nuclear magnetic resonance (NMR), infrared spectroscopy (IR), and X-ray diffraction. In particular, ¹³C nuclear magnetic resonance–cross polarization-magic angle spinning (¹³C NMR CP-MAS) spectroscopy allows to identify and discriminate the adsorbed calcite, that is a diagenetic contaminant, from the structural one of apatite and ¹H NMR-MAS spectroscopy shows how the degradation of organic phase of collagen is related to the time. The NMR data are combined with crystalline index, measured by X-ray diffraction, and with the splitting factor obtained by infrared spectroscopy. Moreover, the evaluation of the relative content of biogenic structural carbonate and of diagenetic fluorine is reported.     

A Mössbauer study of some coloured marbles (cipollino mandolato, rosso antico and fior di pesco): implications on the nature of their colour

⁵⁷Fe Mössbauer spectroscopy permits an explanation of the formation of the iron-bearing species present in three types of coloured marbles, known as cipollino mandolato, rosso antico and fior di pesco. Structural Fe²⁺ and Fe³⁺ located in silicates, together with the remains of weakly ferromagnetic hematite, arise from primary sediments. Fe²⁺ located in carbonates and anti-ferromagnetic hematite are formed by redox processes during marble formation. The relative contents of the iron species in the three types of marbles depend on the composition of the primary sediments and on local conditions during metamorphism. Knowledge of the type and amount of the iron species in marbles may help in the reconstruction of the redox processes, which took place during marble formation. The deviations of the Morin transition of the hematites play the role of genetic indicator because purity, crystallinity and the red hues of hematites in marbles can be related to the environment of formation.     

Introduction to the Plenary Session on the 30th Anniversary of The Performing Arts: An Economic Dilemma by Baumol and Bowen — Ninth International Conference on Cultural Economics Boston 8–11 May 1996

Journal of Cultural Economics -     

超大城市中的公共空间生活意象 ——夜市从纯商业向文创活力方向发展研究

中国城市的公共空间中一直存在群众自发形成商业活动的传统.在超大城市拥挤且有限的公共空间里,如何创造群众自发参与的公共空间,形成积极的城市生活意象,是值得深入思考的问题.中国有很多"草根夜市",是大城市作为"不夜城"的重要组成部分.但随着城市的发展,传统的夜市形式逐渐被取缔.以上海、武汉等超大城市为研究对象,调研夜市发展...     

A procedure for determining the chemical composition of binder and aggregate in ancient mortars: its application to mortars from some medieval buildings in Pisa

The use of a scanning electron microscope equipped with a microanalytical system is proposed for characterising ancient mortars. A calculation procedure is presented that allows a determination of the binder and aggregate compositions (including volatile components) from microprobe data collected on the binder, and chemical, mineralogical, petrographical and physical data collected on the mortar bulk sample. The proposed procedure is applied to 11 mortar samples from three historical monuments built in Pisa throughout the Middle Ages. The binder of the analysed samples consists of a carbonate crystalline fraction and an amorphous carbonate-free fraction that makes up from 20 to 60 % by weight of the binder. The aggregate composition, on average, is close to that of the Arno River sands.