Raman microprobe analysis of stucco samples from the buildings of Maya Classic Copan

Micro-Raman spectroscopy has been applied to painted stucco samples from three buildings at the Maya site of Copan, Honduras. The buildings, Clavel (AD 450–550), Ani (AD550–650) and Structure 10L-22 (AD730,) date from three phases of the Classic Period (AD400–820) acropolis construction. The red pigment has been identified as haematite and the stucco as a mixture of calcite particles dispersed throughout a calcite based lime wash stucco. The physical structure of the stucco changed through time, indicating a refining of production techniques over this period. By combining Micro-Raman spectroscopy with other micro-ATR infrared spectroscopy and environmental scanning electron microscopy a detailed investigation of the materials and production techniques used to decorate these buildings has been made. Differences in the mineralogy of the red pigment used on each building indicate a different geological pigment source for each period.     

唐张臣和墓彩绘陶质文物的拉曼光谱和X衍射分析

利用拉曼光谱和X衍射方法,对张臣和墓彩绘陶质文物颜料及胎体进行分析,结果表明各种颜料保存基本完好,为以后科学保护修复这批彩绘陶质文物提供了科学依据。同时也证明,在样品量极少的情况下,利用拉曼光谱和X衍射等方法可有效鉴别古代颜料的种类及文物胎体的成分。     

Can the Raman spectrum of anatase in artwork and archaeology be used for dating purposes? Identification by Raman microscopy of anatase in decorative coatings on Neolithic (Yangshao) pottery from Henan,China

Scanning electron microscopy/energy dispersive X-ray analysis has earlier shown that the white background layer (slip) on painted pottery sherds (Yangshao culture, Henan, China, 4200 BC) is composed of kaolinitic clay containing titanium in the assumed form of TiO₂ at just 1 wt%. The same samples of white slip have now been studied by Raman microscopy, revealing bands characteristic of anatase, but none from the majority species, the matrix of kaolinitic clay. These results highlight the extraordinarily intense Raman scattering from even trace amounts of anatase and thus the need to recognise that, although the colours of archaeological artefacts are almost always determined by the nature of the matrix, the Raman spectrum may be determined by a highly scattering trace component such as anatase. The significance of anatase as a potential date-marker pigment on works of art and archaeological artefacts is discussed.     

Identification of colourants in icons of the Cretan School of iconography using Raman spectroscopy and liquid chromatography

The stratigraphies of twenty five (25) samples removed from twenty (20) icons of the Cretan School of iconography are studied using Optical Microscopy and micro-Raman spectroscopy. The objects are dated in 15th–17th c. and belong to the collection of the Benaki Museum, Athens, Greece. Cinnabar, red ochre, minium, yellow ochre, azurite, malachite, lapis lazuli, lead white, carbon black, and indigo are identified in the cross-sections of the icon samples using Raman spectroscopy.     

西藏拉萨大昭寺转经廊壁画制作工艺研究

古代壁画是一定时期政治、经济、文化、艺术和科技发展水平的物质反映,因此,利用现代科技分析手段提取其信息并将之与古代文献结合,则可逆推其制作工艺和判定其制作时间,进而确定其历史价值、科学价值和艺术价值,为艺术史研究和保护修复提供信息。本工作利用拉曼光谱(Raman)、偏光显微镜(PLM)、扫描电子显微镜与能谱仪(SEM-EDS)、红外光谱(FT-IR)和X射线衍射(XRD)在西藏大昭寺转经廊壁画样品分析中获取的信息,结合文献,确定西藏拉萨大昭寺转经廊壁画绘制于清代晚期至20世纪80年代之间。此幅壁画地仗使用了阿嘎土,与文献记载一致;白粉层使用立德粉、碳酸镁和方解石等,与文献记载用白胶浆或者黄胶浆相异。同时发现壁画颜料采用藏族传统绘画配色方法。     

新疆和田达玛沟佛寺遗址出土壁画颜料分析

达玛沟佛寺是新疆和田地区重要的佛教遗址,具有极高的佛教及艺术价值,对我国乃至东亚的佛教艺术都有着重要的影响。为研究新疆达玛沟佛寺遗址出土壁画颜料成分及工艺,以壁画文物残块为研究对象,利用体视显微镜、X荧光光谱仪、X射线衍射仪、拉曼光谱仪、偏光显微镜等多种仪器对其进行了分析鉴定。结果表明,达玛沟佛寺所使用的颜料全部为矿物颜料,其中蓝色颜料为青金石,绿色颜料为氯铜矿,白色颜料为石膏,红色颜料为朱砂,褐色颜料为铁红,赭黄色颜料为铁黄。该研究为探索中国西域佛教史、美术工艺史及后期修复保护材料、工艺选择提供科学依据。     

Investigation of chemical changes in bone material from South African fossil hominid deposits

The bone fragments of the Australopithecus Africanus from the dolomitic cave in the Cradle of Humankind in South Africa have been studied by the use of several spectral techniques. The aim was to establish their degree of preservation and possibilities of inferring the life conditions from them. X-ray diffraction studies revealed the transformation of the mineral components partially into fluoroapatite form with addition of goethite, birnessite and quartz phases and with surprisingly well preserved collagen remains. Several important chemical elements were detected by using the electron (EPMA) and synchrotron-based X-ray fluorescence (XRF) microprobes. Among them, Sr and Zn were distributed in a way following the distribution of Ca, the main element of the bones. We suspect the immanent crystallographic substitution of Ca in this case in native bone. Iron followed the distribution of Sr but while Sr is distributed in a continuous way in more rigid locations, iron occurs mainly in the edge zones of the bones and in spot-like inclusions inside. Some part of the spots located in a very edge of bone is also filled with Mn and Cu. It suggests that the porosity and fracture of bones plays a more significant role in the localization of Fe, Mn and Cu. They also form a rigid thin layer (100–250 μm) avoiding further penetration. As (as AsO₄³⁻?) distribution pattern is unique and seems to occur in those locations where the concentrations of Sr are small. The conditions for bone penetration as determined from Eh-pH diagrams suggest that is rather impossible to preserve the organic matter in locations of Mn and also that Mn and Fe hardly can meet in the same spots.     

Technological, elemental and colorimetric analysis of an engraved ochre fragment from the Middle Stone Age levels of Klasies River Cave 1, South Africa

It is generally accepted that abstract and iconographic representations are reflections of symbolic material culture. Here we describe a fragmented ocherous pebble bearing a sequence of sub-parallel linear incisions. These were produced by a lithic point and may represent one of the oldest instances of a deliberate engraving. The object was recovered from Middle Stone Age II levels of Klasies River Cave 1, South Africa, and is dated to between 100,000 and 85,000 years ago. Microscopic analysis reveals that the surface of the object was ground until smooth before being engraved with a sequence of sub-parallel lines made by single and multiple strokes. X-ray fluorescence and colorimetric analysis of the object and a sample of twelve additional ochre pieces from the same level reveals that the brown colour and Manganese-rich composition renders the engraved piece distinct. This suggests that a particular type of raw material may have been selected for engraving purposes. Although the purpose of marking this object remains uncertain, its detailed analysis adds relevant information to previously published occurrences of Middle Stone Age engraved objects and contributes to clarify their distribution through time and space.     

EDXRF analysis of pigment used for the decoration of Mleiha pottery

Energy dispersive X-ray fluorescence spectroscopy was utilized for the analysis of the elemental composition of pigment used to decorate pottery artifacts belonging to the Mleiha period (3rd c. B.C–3rd c. A.D).     

弦歌台大成殿文物建筑彩绘颜料成分分析

弦歌台又被称为绝粮祠,整体布局以中轴线为中心呈现东西对称,现存建筑的规制为三进院落,从南向北依次为正门、戟门、大成殿、弦歌书院。大成殿作为弦歌台最核心的建筑,外观气势宏伟,彩绘精美绝伦,是我国东部地区规格较高的孔庙建筑之一。弦歌台大成殿在自然环境和人为因素的长期影响下,彩绘表面出现了褪色、龟裂、颜料脱落等多种病害,彩绘修复工作已成为当前文物保护亟待解决的棘手问题。本工作对彩绘样本的层位和形制进行详细分析,从剖面和表面等多角度进行全面研究,发现大部分彩绘样本由内向外的结构依次为基底层、地仗层、颜料层,蓝色彩绘样本所使用的地仗层为传统的单披灰工艺,与之不同的是红色彩绘样本为无地仗彩绘,红色颜料层直接绘制于基底层上,推测这可能与时代的发展及工艺的变化有关。为了更好地服务文物进行科学保护,需要了解大成殿彩绘颜料成分及制作工艺等。采用超景深微观分析、扫描电镜及能谱仪分析、显微拉曼光谱分析等现代技术及方法,对彩绘颜料样本进行了层位结构、微观及成分检测分析。结果表明,在制作工艺上,大成殿彩绘颜料层剖面多为两层以上叠加,是明显的重层彩绘,说明历史上至少经历过两次以上重绘。同时发现大成殿彩绘颜料层既有重...     

汉陶俑彩绘颜料表面特征分析

利用色度仪、反射密度计和显微分析技术,对汉代陶俑彩绘颜料进行了综合研究。测定了各种颜料层的色度、密度和颜料表相的显微结构信息,获得各种颜料的色度分布范围,表征出彩绘颜料层的密度和风化状况,关联分析了颜料密度与颜料特征之间的关系,构建了球体色度容差评估模型,为颜料层表面的色泽评价提供定量化评价,为陶俑彩绘颜料保存时间尺度的评估提供分析数据,为陶俑彩绘的科学保护提供科学依据。     

山东长清灵岩寺宋代罗汉像彩绘分析研究

山东省济南市长清区灵岩寺彩绘罗汉像是我国宋代泥塑罗汉的代表作,具有极高的历史、艺术和科学价值。但罗汉像保存现状较差,彩塑存在颜料脱落、残损、酥碱等病害,亟待保护修复。为此,本工作选取彩绘脱落严重的两尊宋代彩塑罗汉像,利用光学显微镜(OM)、拉曼光谱(Raman)、扫描电子显微镜与能谱仪(SEM-EDS)等分析其彩绘颜料样品。结果表明,彩绘罗汉像从塑制之初至今,经过数次彩绘,可确定的多达六次。黑色颜料为炭黑(C);红色颜料为朱砂(HgS),铅丹(Pb_3O_4),以及朱砂、铁红(Fe_2O_3)和方解石(CaCO_3)混合物;绿色颜料为巴黎绿(Cu(C_2H_3O_2)·3Cu(AsO_2)_2)和舍勒绿(Cu(AsO_2)_2),还发现有斜氯铜矿(CuCl(OH)_3)及其与铅白(2PbCO_3·Pb(OH)_2)的混合物;橙色颜料为铅铬黄(PbCrO_4)和铅丹混合物;蓝色颜料为蓝铜矿(2CuCO_3·Cu(OH)_2),人工合成群青(Na_3CaAl_3Si_3O_(12)S);白色颜料为铅白和方解石;黄色颜料为铁黄(FeO(OH));金色为金箔(Au);沥粉的主要成分是方解石。白色底层为铅白和以硅、铝、钙为主的细白土。彩塑罗汉像重绘过程中,保持了将细白土作为底层和衣领镶边沥粉贴金的传统。彩绘颜料所用铅铬黄、巴黎绿、舍勒绿表明,彩塑罗汉像最近一次彩绘在清末之际,与文献记载相符,且这些人工颜料应是西方舶来之物。本分析研究结果为灵岩寺罗汉像艺术史研究提供了丰富信息,同时为保护修复工作开展提供了可靠依据。     

Application of X-ray fluorescence imaging to ceramics from the American Southwest

We have used synchrotron-based X-ray fluorescence imaging (XRFI) to examine sherds of painted ceramics from prehistoric cultures of the American Southwest. These sherds are very well suited to XRFI analysis. Paints can generally be detected and distinguished by the fluorescence intensities of their constituent elements. Spatial maps of element distributions yield the spatial distribution of pigments. Pigments can be distinguished that are (or have become) visually similar; layers that have been obscured by overpainting can be examined; and pigment residues can be distinguished from surface contaminants deposited after painting and firing. As a result, XRFI allows the painted motifs to be clarified and hidden features to be revealed. Furthermore, the very rapid scanning and high sensitivity elemental detection possible with synchrotron-based XRFI facilitate measurements on large collections of sherds, allowing an integrative rather than anecdotal analysis.     

A non-invasive study of Roman Age mosaic glass tesserae by means of Raman spectroscopy

Ancient mosaic tesserae are a range of materials of very varied and complex nature, including pottery, stone and glass. Raman spectroscopy is a powerful tool for the analysis of all these kinds of materials. In the particular case of glasses, this technique can be used both for a study of surface weathering and for the characterization of bulk structure, but it has not yet been extensively used for the characterization of mosaic glass tesserae. We carried out Raman analyses on a set of Roman and Late Antiquity period mosaic glass samples, which allowed a good characterization of both the glass matrix and the crystalline inclusions. All the samples show the typical Raman signatures of soda-lime-silicate glasses. Several crystalline phases were also identified, being relics of raw materials used during the glass manufacturing process, such as quartz and feldspars, or linked to the glass color/opacification, such as bindheimite and cuprite. The analyses also led to the identification in some blue, turquoise and green tesserae of calcium antimonate, whose Raman signature has only recently been recognized in the scientific literature on mosaic glasses. Some emphasis is given to the analysis of red lead-containing tesserae, colored with Cu⁺ ions or even Cu⁰ (or Au⁰) metal nanoparticles. Samples with peculiar compositions, as well as “modern” (and restoration) samples, could quite easily be distinguished from the ancient ones by their Raman spectra.     

Prehistoric hand stencils at Fern Cave, North Queensland (Australia): environmental and chronological implications of Raman spectroscopy and FT-IR imaging results

Raman spectroscopy and FT-IR imaging analyses of cave wall pigment samples from north Queensland (Australia) indicate that some hand stencils were undertaken during a dry environmental phase indicating late Holocene age. Other, earlier painting episodes also took place during dry environmental periods of the terminal Pleistocene and/or early Holocene. These results represent a rare opportunity to attain chronological information for rock art in conditions where insufficient carbon is present for radiocarbon dating.     

In search of the optimum Raman/IR signatures of potential ingredients used in San/Bushman rock art paint

Vibrational spectroscopy (Raman and FTIR) has played an important role in identifying pigments, substrata and deterioration products in rock art studies worldwide: in the laboratory and on-site. However, the detection of organic binders and carrying agents has so far been scarce and the quality of many spectra recorded on-site inadequate. In this study, possible pigments (charcoal, ochre, raptor faeces, thermally treated ostrich egg shell, etc.), binders (fat, egg, blood) and carrying agents (saliva, gall, egg, water) were selected based on artistic considerations and analysed with FTIR and Raman (514.6 and 785 nm excitation, both available in mobile instruments) spectroscopy in order to determine usable marker bands for each ingredient. The resultant marker bands were then used to analyse five ten year old San replica paints. It was found that FTIR spectroscopy is very efficient to identify organic compounds as there is no fluorescence but the broadness of the bands inhibits the exact assignment of many ingredients. A high fluorescence background experienced for many natural products prevented the recording of Raman spectra for all ingredients, in many instances though the sharp peaks usually associated with Raman spectra make identification easier than with FTIR spectroscopy. Most of the ingredients in the paints could be identified, but it is clear that better results are obtained when more that one technique is used.     

Non-destructive analysis of amber artefacts from the prehistoric Cioclovina hoard (Romania)

Amber beads from the Cioclovina hoard (Hunedoara County, Romania), dating from the transitional period between the Late Bronze Age and the Iron Age, were analysed by Fourier transform infrared spectroscopy – variable angle reflectance (FTIR-VAR) and Fourier transform Raman spectroscopy (FT-Raman). The aim was to determine if the raw material came from the shores of the Baltic Sea, on the Amber Route which crosses Central Europe, or if it originated from the area of the main amber occurrences in Romania, in Buz?u County, around the village of Col?i. All applied analyses strongly suggest that a large part of the amber from the Cioclovina deposit has a Romanian origin, and thus no connection with the Amber Route.     

Pigment analysis in Bronze Age Aegean and Eastern Mediterranean painted plaster by laser-induced breakdown spectroscopy (LIBS)

Laser-Induced Breakdown Spectroscopy (LIBS) was used in the examination of Bronze Age painted plaster samples from several sites in the Aegean and Eastern Mediterranean. The elemental content of paint materials was determined in most cases leading to the identification of the pigment used in agreement with data from analyses of the same samples with other established techniques. The analyses demonstrate that a virtually non-destructive technique such as LIBS provides sufficient data for the elemental characterisation of painting materials while in parallel has the capability for routine, rapid analysis of archaeological objects enabling the quick characterisation or screening of different types of artefacts. This certainly shows an important way forward in technological studies of fragile and scarce archaeological material.