FIELD AND LABORATORY MULTI‐TECHNIQUE ANALYSIS OF PIGMENTS AND ORGANIC PAINTING MEDIA FROM AN EGYPTIAN COFFIN (26TH DYNASTY)

This paper describes the physico‐chemical analyses performed on an Egyptian wood coffin on the occasion of its restoration in the hall of the National Archaeological Museum of Parma (Italy), with the aim of investigating the pigments and organic materials originally used. Pigment determination was performed both in situ by a portable energy‐dispersive X‐ray fluorescence (EDXRF) spectrometer and in the laboratory using a micro‐Fourier‐transform‐infrared (micro‐FTIR) and a Fourier‐transform (FT) Raman spectrometer. The identification of organic materials was performed through gas chromatography – mass spectrometry (GC–MS) and micro‐FTIR analysis. Amongst the pigments, special attention was paid to the green, which appeared to be severely degraded and was examined using powder X‐ray diffraction (XRD) and scanning electron microscopy – energy‐dispersive X‐ray (SEM–EDX) in addition to the above‐cited techniques. Other materials used in the polychromatic decorations are Egyptian blue, cinnabar and possibly orpiment, while calcium carbonate was used for the ground layer. The organic materials were identified as beeswax, mastic and gum arabic, sometimes as mixtures.     

TEMPLAR JOINT REPOINTINGS: MATERIALS,TECHNIQUES AND PAINT DECORATION IN MIRAVET CASTLE,SPAIN

The medieval repointings, with incised and painted decoration, observed on the walls of Miravet Castle, Spain, which was built during the 12th century by the Knights Templar, are described, analysed and characterized by X‐ray powder diffraction, SEM–EDS and FTIR. The results demonstrate that the painted decoration preserved on the inner walls of the dining room is original and contemporary with the outer joint repointings. This feature is of great interest as, in this particular case, repointing not only comprised a structural necessity in order to render the wall impermeable to run‐off water, but also played a decorative role.     

Problems of Analysis by FTIR of Calcium Sulphate–Based Preparatory Layers: The Case of a Group of 16th‐Century Portuguese Paintings

This paper provides a contribution to FTIR analysis of calcium sulphate‐based grounds of paintings when a mixture of compounds with different degrees of hydration is present. The study is based on the analysis with that technique, electron microscopy coupled with energy‐dispersive X‐ray spectrometry and X‐ray diffraction of both the grounds of 16th‐century Portuguese paintings and reference samples prepared with anhydrite and calcium sulphate dihydrate bound in an animal glue solution. It is shown that the interpretation of the degree of hydration of calcium sulphate ground samples using FTIR cannot be based solely on the study of the hydroxyl bands, as is usual in routine work, but that small deviations of the S–O vibration bands are an important indicator of the presence of anhydrite in the grounds.     

A preliminary study on using enzymes in cleaning archaeological wood

The main goal of this study was to study and evaluate the effect of hydrolyzing enzymes on the anatomical structure and chemical composition of archaeological wood samples. Pine and beech wood samples, which were taken from anonymous mashrabia, have been cleaned with three types of enzymes then a scanning electron microscopy (SEM) and infrared spectroscopy (FTIR) study were undertaken, to see if any significant structural or chemical differences could be detected between “untreated” and “treated” wood. No dramatic changes in functional groups on the wood surface, as monitored by infrared spectroscopy, occurred in the samples before and after enzymatic cleaning. SEM data, however, show that protease and lipase enzymes may give good results in cleaning wood surface, but the enzyme residues remaining on the cell walls of archaeological wood are another point to consider.     

Discovery of Beeswax as binding agent on a 6th-century BC Chinese Turquoise-inlaid Bronze sword

Recent archaeological field surveys and excavations at Qiaojiayuan, a platform 40 km west of the Yun County in present-day northwestern Hubei Province (central China), revealed four tombs (M₃, M₄, M₅ and M₆) dating back to around 6th to 5th century BC. The grave's layout, artifact assemblages and burial practice indicate that the owners of these four graves were aristocrats of the Chu state. Five turquoise-inlaid bronze artifacts (two swords and three dagger-axes) were excavated. The sword from M₄, imbedded with pieces of well-cut and finely-polished turquoise on its handle, was in a very bad state of preservation and underwent conservation treatment. Some sticky, whitish pastes were exposed when the inlaid turquoises dropped off. The pastes were supposed to be residues of unknown binding agents. Samples of the pastes were collected for FTIR (Fourier Transform Infrared Spectroscopy) and XRD (X-Ray Diffraction) analyses to determine the chemical component(s). The results revealed that the pastes were composed of almost pure beeswax. This indicated that beeswax was used as binding agent in turquoise-inlaid bronzes as early as the 6th to 5th century BC in China. Review of recent technical studies suggested that beeswax was used in early China in several different regions (mostly southern part of China) for at least two different purposes (binding agent and lightening).     

文物彩绘常用胶料的氨基酸组成 及红外光谱特征研究

为了探索鉴定古代文物彩绘胶料的综合分析方法,使用红外光谱仪及氨基酸分析仪对中国古代五种常用文物彩绘胶料的红外吸收光谱及氨基酸组成进行了测定。通过对样品红外光谱特征吸收峰的判别、分析,得出了1653cm-1及1545cm-1处的吸收峰为蛋白类胶料的特征,1076cm-1及1043cm-1处的吸收峰为桃胶的特征,以及奶类同时具有蛋白类胶料及桃胶特征的结果。通过对样品氨基酸组成的分析,得出了动物胶特有羟脯氨酸及较多的甘氨酸,鸡蛋含有较高的天冬氨酸和较低的脯氨酸,奶类的谷氨酸和丙氨酸含量比较高的结果。研究结果表明,通过氨基酸分析结合红外光谱的特征吸收峰,可以基本区分、判定古代文物彩绘常用胶料归属的结论。