The Structure and Chemical Composition of Wall Paintings From Islamic and Christian Times in the Seville Alcazar

Wall paintings from the Islamic epoch (10th to 12th centuries) and the Christian monarchy (14th to 16th centuries) have been recovered in discarded materials and on walls after reconstruction works in the Seville Alcazar. These paintings have spent centuries underground or under a plaster coat. Portable X‐ray fluorescence (XRF) and combined XRF/X‐ray diffraction (XRD) were employed in situ, as well as scanning electron microscopy (SEM–EDX), grazing angle incidence XRD and micro‐Raman spectroscopy, on cross‐section samples to fully characterize the materials in the wall paintings. Using these methods, the fresco technique was demonstrated, and many kinds of pigments were identified in accordance with the various periods of the history of the Alcazar, thus assessing the authenticity of all the wall paintings studied here.     

Physico‐Chemical Characterization of Pigments and Binders of Murals in a Church in Ethiopia

Here, we report the physico‐chemical characterization of wall paintings from the Petros and Paulos church in Ethiopia. This work represents the first technical study of paintings located in Ethiopia, rather than paintings in museum collections outside the country, using diverse analytical techniques. In situ examination with a portable X‐ray fluorescence spectrometer (pXRF) was followed by analysis of samples using optical microscopy (OM), scanning electron microscopy coupled with energy‐dispersive X‐ray spectroscopy (SEM/EDS), micro‐Raman spectroscopy (MRS), attenuated total reflection – Fourier transform infrared spectroscopy (ATR‐FT–IR), X‐ray powder diffraction (XRD) and pyrolysis gas chromatography – mass spectrometry (Py‐GC/MS). The paint stratigraphy, the compositions of the support material, the preparatory and painting layers were studied, as well as the morphology of the pigment particles. The results revealed the use of earth pigments and carbon black. The preparatory layer was uncommon; composed of dolomite, clay rich in clinochlore and sand, in contrast to the more common gypsum and calcite. The binder and the stratigraphic analyses suggested a distempera technique.     

Multispectral documentation and image processing analysis of the papyrus of tomb II at Daphne,Greece

This paper refers to the study of an ancient papyrus, dated ca. 420/430 BC, found in 1981 during an excavation at Daphne, Athens, Greece, using multispectral imaging combined with image processing analysis. It was assumed that the papyrus contained ancient Greek musical notation but the condition of the object hindered the drawing of any conclusion based only on visual examination. This fact, combined with the significance of the object itself, as it is the oldest papyrus which carries Greek text, pointed to the application of non-invasive techniques to enhance its readability. The multispectral imaging carried out in the range of 420–1000 nm enabled the detection of more letters on surface layers, at various places and orientations. False colour imaging proved to yield better results in distinguishing the letters compared to single wavelength recording. In some cases, letters from several layers underneath are revealed in the infrared. The letters present different greylevels according to the layer they belong. An interesting result coming from a simple subtraction of the infrared image at 1000 nm from the visible one at 660 nm is that different layers of the papyrus can be distinguished. The Application of Principal Component Analysis (PCA) showed that the best results, as far as the extraction of the letters from the background is concerned, are obtained when the second and the third images are merged. The automatic extraction of the letters is feasible to some extent but there is a certain amount of noise with similar characteristics that cannot be removed.     

Identification of Green Pigment Used in Persian Wall Paintings (ad 1501–1736) Using PLM,FT–IR,SEM/EDX and GC–MS Techniques

The technique of oil painting was introduced to Iran via a cultural exchange with Europe in the Safavid period (ad 1501–1736). Since the first attempt at scientific conservation of wall paintings in Iran in the 1960s, the nature of green pigment used in Persian wall paintings has not been clear, although work on contemporary miniature paintings has identified malachite and verdigris. PLM, FT–IR, SEM/EDX, GC–MS and the study of contemporary historical treatises of the Safavid period were the main tools used in the present study to identify the green pigments in Persian (oil‐based) wall paintings. Eight samples taken from the two famous Safavid buildings, Chehel Sotoon Palace and the Sukias House in Isfahan, were analysed. Here, the identification of copper‐based pigment and of verdigris in oil as oleate amends the existing knowledge of the green pigment used in these paintings. It also suggests that oleate was introduced to Persian artists via the European influence on Persian painting as a result of cultural exchange in the Safavid period, when the technique of Persian painting changed from tempera to oil painting. However, as verdigris in oil and resin can appear as oleate over time, it is unknown whether the Persian artists did this deliberately or accidentally.     

一种基于形状和颜色特征的建筑彩画检索方法

为了能够在建筑彩画数据库系统中自动找出与所给事例彩画相似的彩画及各种相关数据资料,需要进行彩画图像检索。给出了一种基于形状和颜色特征的建筑彩画检索方法,第一步是对彩画基本类型进行检测识别,先对彩画图像进行边缘检测,再利用先验模板对边缘图像进行匹配,然后根据匹配结果来识别彩画的基本类型。第二步是在相同的基本类型中进行相似性匹配,主要是在HSV空间中统计颜色直方图特征矢量,以同类型彩画之间颜色直方图矢量的相似度大小作为检索依据,最后给出检索结果。实验表明,本方法的检索结果更符合人眼对相似性的感知。     

Wall Paintings from the Roman Emona (Ljubljana,Slovenia): Characterization of Mortar Layers and Pigments

This study concerns the investigation of mortar layers and pigments of wall paintings from the Roman town of Emona (Ljubljana, Slovenia). Fragments of wall paintings consist of up to three preserved mortar layers. The mineralogical–petrographic compositions of the mortars were determined by means of optical microscopy and FT–IR spectroscopy. The investigated samples were divided into several groups based on similar thicknesses of the mortar layer, the binder colour and the composition of an aggregate. Furthermore, the results of mercury intrusion porosimetry showed that mortar layers consisting of carbonate grains exhibited lower porosity with respect to layers with mainly silicate grains, which is attributed to the angular shapes of carbonate aggregate. This is in accordance with the drilling resistance measurement system test (DRMS), confirming that layers with angular carbonate grains are harder than those with addition of rounded silicate ones, due to the good packing effect. The wall paintings were mainly executed using the fresco technique, while for some details secco was used. The identified pigments were red and yellow ochre, green earth, Egyptian blue, carbon black and lime white; all of them belonged to the so‐called austere pigment, which is quite common in Roman wall paintings.     

DISTINCT,LATE BRONZE AGE (c. 1650 bc) WALL‐PAINTINGS FROM AKROTIRI,THERA, COMPRISING ADVANCED GEOMETRICAL PATTERNS*

This paper studies a set of wall‐paintings of the Late Bronze Age (c. 1650 bc ) initially decorating the internal walls of the third floor of the edifice called ‘Xeste 3’, excavated at Akrotiri, Thera, whose restoration is now in progress. It deals with the methods used for the drawing of the geometrical figures appearing in these wall‐paintings. It is demonstrated that most of the depicted configurations correspond with accuracy to geometrical prototypes such as linear spirals and canonical polygons. It is pointed out that the steady lines of the figures, their remarkable repeatability, the precision of the geometrical shapes and their even distribution in the wall‐paintings indicate a very distinctive use of the ‘Xeste 3’ third floor, which is now investigated.     

X射线摄影技术在漆下彩画识别中的应用

针对遭到油漆涂抹的传统彩画作品,为了实现对图案的无损提取,本研究使用X射线摄影技术,又称X光成像(照相)技术,利用X射线对不同物质的穿透能力有别,在底片上成像的灰度与物体材质、密度、厚度等密切相关的特点,最终得到分界清晰的黑白图像。此类病类常见于建筑彩画中,建筑彩画意蕴深厚、技法繁缛,极具研究价值,但其中很多关键信息却已失传。经X射线摄影技术辅助,封存在油漆层下的彩画图案得以重见天日,此法与其他修复方法之间形成互补,为漆下彩画的完美修复提供了可能。     

蒙古国博格达汗宫建筑木构件彩绘工艺及材料分析

本研究应用剖面显微观察和显微红外光谱等分析手段对蒙古国博格达汗宫建筑彩绘的制作材料和工艺特征进行了分析,剖面显微观察显示历次彩绘重彩层次结构;紫外显微剖面观察还发现了彩绘层中施胶的信息。分析结果还显示：博格达汗宫建筑彩绘工艺与中国彩绘传统工艺基本相同。     

莫高窟壁画彩塑表面降尘调查研究

通过对莫高窟壁画彩塑表面降尘进行收集，分析降尘粒径分布、化学组成、显微形貌、可溶盐含量等理化性质，进而研究降尘对莫高窟壁画彩塑的影响。研究结果发现：莫高窟壁画彩塑表面的降尘大部分为地壳源矿物，对窟内壁画、彩塑带来的潜在危害是物理遮盖和磨蚀等作用，在更长的时间尺度上，降尘会对壁画彩塑具有潜在的盐蚀等化学威胁。莫高窟壁画彩塑表面降尘是导致壁画彩塑产生病害的一个不可忽视的重要因素。研究的结果为莫高窟壁画彩塑预防性保护提供基础数据。     

北宋富弼墓壁画的揭取及修复保护

2008年3月,在洛阳北郊一处建设工地发现了北宋名相富弼的墓葬,墓中出现了较为罕见的北宋门庭仪卫和玄武等壁画形象。为更好的保护和利用这一重要文物,洛阳古代艺术博物馆将墓中壁画进行了揭取、修复。使用粘贴纱布法将壁画从墓葬支撑体上揭取下来;然后使用Primal SF-016等胶液渗透加固壁画,以Primal SF-016和细沙配制而成的砂浆作为隔离层材料,以蜂窝铝板作为新的支撑体材料,并使用“影线法”将壁画残缺填补处着色补绘。从目前结果看,整体修复效果良好,这可对国内壁画的修复保护提供以参考和借鉴。     

壁画的生物腐蚀与防护研究进展

近年来生物因素对壁画的腐蚀破坏作用受到了众多文物保护工作者的重视,针对壁画生物腐蚀的防护研究取得了可喜的成果。本文从可以造成壁画损害的生物因素出发,综述近年来壁画生物腐蚀研究的成果,分别从小型动物、昆虫、植物、微生物以及游客五个方面阐述对壁画的影响,并讨论了进行生物腐蚀防护的措施和研究方向:对小型动物,使用一些物理性的防护措施,应成为有害动物防护研究的重点;对昆虫,防治重点是减少昆虫的植物性食物,昆虫中存在的捕食关系也是限制昆虫种群数量的一个新的突破口;对微生物,一些具有抑菌效果的无机材料或许可成为生物杀菌剂的替代品;对植物,有害植物的清除技术的提高和有益植物的筛选和应用需要进一步研究;对游客,建立人工复制的壁画或者设立数字影像代替原有文物壁画供人们参观,是目前一条行之有效的措施。本综述成果可为以后的壁画保护工作提供理论指导。     

基于丰度反演及光谱变换的书画霉斑虚拟修复

古书画在保存过程中容易滋生霉斑病害，霉斑不仅影响书画的外观，还会对纸质文物造成不可逆转的永久性破坏。为了给霉斑清洗提供直观参考，提出基于丰度反演及光谱变换的书画霉斑提取与虚拟修复方法。选取与霉斑区域光谱曲线存在明显差异的450～600 nm之间244个波段作为特征波段，通过连续最大角凸锥端元提取与灰度分割，提取霉斑区域。再对高光谱影像进行主成分变换，选取包含信息量最大的前三主成分合成影像，利用Criminisi算法对霉斑区域进行修复，再将修复后的影像进行主成分逆变换，完成高光谱影像的虚拟修复。以中国近现代画家倪田的《捕鱼图》为例进行了研究，发现修复后的霉斑区域与画体融入性较好，边界自然平滑，均方根误差值普遍变小。研究结果可为书画霉斑清洗提供直观的修复依据，具有较强的实用性。     

DOMUS AUREA,THE ‘SALA DELLE MASCHERE’: CHEMICAL AND SPECTROSCOPIC INVESTIGATIONS ON THE FRESCO PAINTINGS

In this paper, data collected from the wall fresco paintings of room 114, called the ‘Sala delle maschere’, of the Domus Aurea in Rome is analysed. The chemical composition of the efflorescence is investigated by infrared spectroscopy. The colour palette is determined by means of EDXRF, Raman spectroscopy and visible reflectance spectroscopy. EDXRF has allowed an extensive mapping of the elements present in the pigments and plaster; whilst in‐situ Raman spectroscopy has been determinant for attributing the molecular composition of the pigments in a number of doubtful cases. Most pigments identified are typical of Imperial Roman fresco paintings (first to fourth centuries AD) ( Ward‐Perkins 1981 ); more interestingly, we found evidence of fragments painted with Egyptian blue, which was normally used mostly in official rooms.     

Documenting and Analyzing Rock,Paintings from Torres Strait,NE Australia,with Digital Photography and Computer Image Enhancement

Abstract

The deterioration of rock-art over time is an important concern for indigenous communities, archaeologists, rock-art researchers, and cultural heritage managers. Computer enhancement has emerged as an important tool in viewing poorly visible rock paintings. While most studies regarding this technique explore the methods associated with computer enhancement there is little discussion of the results that can be generated beyond the recovery of images. This article presents results from the application of computer enhancement methods to rock paintings from the Torres Strait region in NE Queensland. The results obtained through the computer enhancement of deteriorated rock paintings are used to reveal degrees of preservation, interregional interaction, and previously undocumented spatial patterning across the strait.     

天梯山石窟9窟彩塑与壁画地仗矿物 及颜料分析

天梯山石窟,即北凉石窟,在国内史学界誉为中国古代石窟鼻祖。据考证,9窟彩塑与壁画制作始于唐代,后经历代多次重绘。针对目前彩塑与壁画的保存现状及需要修复的状况,本研究运用现代分析仪器与技术,对9窟现存的彩塑、壁画进行了科学分析。其中,对彩塑及壁画地仗土层矿物进行了X射线衍射分析,对重层彩绘颜料进行了X射线衍射、X射线荧光分析;另外,对清理彩塑地仗时发现的植物茎秆及附属物,采用偏光显微分析技术进行了材质鉴定。分析和鉴定结果表明:9窟现存彩塑及壁画地仗土层具有相同的矿物组成,基本包括石英、长石(斜长石、少量的K-长石)、云母(白云母、绿泥石、伊利石、斜绿泥石)、方解石、少量石膏,并确定植物茎秆材质为稻草;在使用的彩绘中,黑色为墨,红色颜料有朱砂、铅丹和铁红,蓝色颜料为石青,白色颜料以方解石为主,有少量的石膏。本结果可为后期天梯山石窟的全面复原修复提供参考资料。     

基于光谱成像的彩绘文物新应用与新方法

目前基于光谱成像的彩绘文物分析主要集中在颜料分析、信息增强、隐含信息挖掘等方面,分析方法主要采用遥感图像处理软件。针对文物数据专门分析方法研究尚显不足的问题,提出基于光谱成像的彩绘文物新应用与新方法。主要包括基于最小噪声分离(MNF)变换感知修复区域的新应用,利用感兴趣区域分析与融合挖掘彩绘文物隐含信息以及基于稀疏非负矩阵欠近似彩绘文物线稿提取的新方法。通过在唐墓壁画、彩绘泥塑以及手绘绢画上的实验,发现光谱成像可以有效感知修复区域,提出的新方法可以有效挖掘隐含信息以及提取线稿,对基于光谱成像的彩绘文物分析研究具有重要意义。     

岩鸽排泄物对壁画损害特征研究

鸟类排泄物是造成石窟寺壁画、彩塑污染的主要因素之一,科学剖析鸟类排泄物对壁画的损害特征是此类污染物有效清除的前提。本研究利用傅里叶变换红外光谱(FTIR)、气相色谱-质谱联用(GC-MS)、X射线衍射(XRD)等方法分析了炳灵寺石窟壁画表面岩鸽排泄物成分,采用扫描电镜-能谱仪(SEM-EDS)、便携式显微镜、偏光显微镜(PLM)表征了鸟类排泄物对模拟壁画的微观损害特征。结果表明,岩鸽排泄物成分主要由尿酸、纤维素、多肽类有机物,以及以石英为主的无机盐组成。排泄物造成壁画覆盖污染、颜料层和地仗层侵蚀、颜料颗粒间原始粘附结构破坏,导致颜料层起甲、脱落,可溶盐活动及其他生物侵蚀。研究结果对于古代壁画的科学保护与修复具有指导意义。