A Study of Biodeterioration and Chromatic Alterations of Painted and Gilded Mummy Cartonnage at the Saqqara Museum Storeroom,Egypt

Microbial biofilms have developed on the surfaces and within the painted and gilded layers of mummy cartonnage at the Saqqara museum storeroom in Giza, Egypt. SEM–EDX, XRD and FT–IR–ATR techniques were applied to analyse the coloured and gilded materials, ground layer, textile support and binder used for the cartonnage. Aspergillus niger (24.8%), Penicillium chrysogenum (21.5%) and a novel cartonnage‐biodegrading bacterium, Bacillus sonorensis (23.7%), were the most abundant microbes growing over the cartonnage surface. In addition, Aspergillus tamari (15.4%), A. fumigates (8.1%) and Fusarium solani (6.5%) were identified. The pigments comprised Egyptian blue (cuprorivaite), cinnabar (red), orpiment (yellow) and green pigment made from a mixture of cuprorivaite and orpiment. Gold leaf was used for the gilded layer, calcium carbonate and gypsum comprised the ground layer, gum arabic was the binding medium and the fibre base was a fine linen textile. Microbial colonization tests were performed on aged cartonnage replica samples made from linen and pigments of similar composition to ancient pigments found in the cartonnage. Each sample was inoculated separately with A. niger, P. chrysogenum and B. sonorensis. Yellow orpiment samples were the exception, as no colour change was detected after colonization by the examined micro‐organisms.     

THE CHEMICAL COMPOSITION OF BLUE PIGMENT ON CHINESE BLUE‐AND‐WHITE PORCELAIN OF THE YUAN AND MING DYNASTIES (ad 1271–1644)*

The chemical compositions of the glazes and pigments of 39 blue‐and‐white porcelains of Ming Dynasty date and three of Yuan date were examined by SR‐XRF. Both the analysis of the Fe/Mn ratio in the light blue areas of the glaze and a comparison of the Fe/Mn values between light blue, dark blue and clear glaze areas reveals that the samples can be divided into three groups. The results indicate that there are two significant changes of provenance of blue pigment during the Ming Dynasty and that some kinds of pigment were most probably imported from the Middle East. Considering literature records and other scholars’ studies, an outline picture of the pigment used on Chinese blue‐and‐white porcelain produced in Jingdezhen in the Yuan and Ming Dynasties is presented.     

RESEARCH ON THE PIGMENTS FROM PAINTED CERAMICS EXCAVATED FROM THE YANGQIAOPAN TOMBS OF THE LATE HAN DYNASTY (48 BC – AD 25)

The analysis of pigments on painted ceramics excavated from the Yangqiaopan Tombs of the late Western Han Dynasty was undertaken using optical microscopy (OM), micro‐Raman spectroscopy (μ‐RS), scanning electron microscopy with energy‐dispersive X‐ray spectrometry (SEM–EDS), X‐ray diffraction (XRD) and Fourier‐transform infrared spectroscopy spectra (FTIR). The pigments were identified as red lead (Pb₃O₄), carbon (C), malachite [Cu₂CO₃(OH)₂], Chinese purple (BaCuSi₂O₆) and illite {[K,H₃O]Al₂Si₃AlO₁₀(OH)₂}. Fibrous materials were observed in some pigment samples. When observed by SEM, one showed a large amount of fibre in solidified gum, which indicated that gum of ramie could have been used as the binding medium to make the pigment particles adhere together. These results provide significant insights into the characteristics of these pigments in the Qin and Han Dynasties.     

Pb and Sr Isotopes and the Provenance of the Painting Materials of Cornelius Krieghoff in 19th‐Century Canada

Radiogenic lead and strontium isotope data are presented for lead‐ and calcium carbonate/barium sulphate‐containing paint and ground samples from 15 paintings, executed between 1844 and 1871, by 19th‐century Canadian artist Cornelius Krieghoff. Like many artists of this era, Krieghoff used lead‐based pigments such as lead white, chrome yellow and Naples yellow, and extenders such as calcium carbonate and barium sulphate. The lead isotope analyses of the majority of these pigments are consistent with the isotopic compositions of lead mined from European lead deposits in England and/or Germany. However, three samples from Krieghoff's early career yield lead isotope compositions that are much more radiogenic than European sources. The lead isotope compositions of these three samples are consistent with the addition of a more radiogenic lead component that is similar to the lead derived from North American lead deposits in Missouri and Illinois (Mississippi Valley Pb–Zn type deposits). The strontium isotope compositions of the extenders suggest that the raw materials for calcium carbonate or barium sulphate extenders were largely derived from Palaeozoic to modern‐day marine environments. This study shows that pigments manufactured from North American lead were being incorporated into Canadian paintings as early as 1844.     

PIGMENT IDENTIFICATION IN GREEK POTTERY BY RAMAN MICROSPECTROSCOPY*

Raman microspectroscopy (RMS) is now established as a key technique for the identification of pigments of archaeological pottery that permits the in situ study of art objects by a non‐destructive procedure. The information obtained represents a great aid to restoration and conservation techniques. In this work, the chemical nature of the red, black and white pigments of five samples of Greek pottery from the end of the fifth century and the first half of the fourth century bc , exhumed from the Iberian necropolis of Cabezo Lucero (Guardamar del Segura, Alicante, Spain), has been identified. The black and the red pigments are found to be magnetite (Fe₃O₄) and hematite (α‐Fe₂O₃), respectively. The white pigment is found, for the first time, to be composed of alumina (α‐Al₂O₃ and γ‐Al₂O₃) probably yielded by the thermal decomposition of Greek bauxite.     

SYNTHESIS AND ACID RESISTANCE OF MAYA BLUE PIGMENT*

Maya blue is an organo‐clay artificial pigment composed of indigo and palygorskite. It was invented and frequently used in Mesoamerica in ancient times (eighth to 16th centuries). We analyse in this paper one of the characteristics of Maya blue that has attracted the attention of scientists since its rediscovery in 1931: its high stability against chemical aggression (acids, alkalis, solvents, etc.) and biodegradation, which has permitted the survival of many works of art for centuries in hostile environments, such as the tropical forest. We have reproduced the different methods proposed to produce a synthetic pigment with the characteristics of the ancient Maya blue. The stability of the pigments produced using either palygorskite or sepiolite has been analysed by performing acid attacks of different intensities. The results are analysed in terms of pigment decolouration and destruction of the clay lattice, revealed by X‐ray diffraction. Palygorskite pigments are much more resistant than sepiolite pigments. It is shown that indigo does not protect the clay lattice against acid aggression. We show that Maya blue is an extremely resistant pigment, but it can be destroyed using very intense acid treatment under reflux.     

便携式X射线荧光现场分析壁画颜料适用性研究——以西藏拉萨大昭寺壁画为例

便携式X射线荧光光谱仪作为快捷的无损分析技术,广泛应用于壁画文物的现场分析中.本文利用便携式X射线荧光光谱仪分析了西藏拉萨大昭寺转经廊壁画,选取部分样品,利用实验室X射线荧光分析,发现所分析颜料的主要显色元素具有一致性,并利用拉曼光谱确定了壁画颜料的成分.通过比较研究,发现便携式X射线荧光光谱仪可确定大部分色彩较为纯正的颜料的成分,同时,由于西藏拉萨大昭寺壁画颜料的杂多性,对于含砷的橙色颜料、含砷或含铅与含铁的黄色颜料、含铜砷的绿色颜料、含钙硫的白色颜料、群青与孔雀石的混合颜料则需结合拉曼光谱确定之.本研究工作显示,利用便携式X射线荧光光谱仪开展现场检测,可极大地减少实验室分析样品的取样数量,有利于壁画颜料的无损分析与微损分析.     

陕西安康紫阳北五省会馆壁画颜料分析研究

陕西安康紫阳北五省会馆壁画是目前陕西省境内发现的最大的一处建筑壁画,为了解其颜料组成,本工作采用X射线荧光、偏光显微镜、X射线衍射、激光显微拉曼光谱及扫描电镜能谱分析相结合的分析方法,对颜料样品进行了分析。结果表明,北五省会馆壁画除正殿发现一处红色染料外,其他均为无机颜料;红色颜料主要是铅丹、朱砂、铁红;绿色颜料为氯铜矿、石绿、斜氯铜矿;蓝色颜料的主要成分是普鲁士蓝、smalt、石青;黄色颜料为雌黄、铁黄;褐色颜料的主要成分是铁红及铅丹的变色产物二氧化铅;黑色为炭黑;白色颜料主要是铅白,且多使用铅白作为调色颜料。研究结果对于了解清代民间壁画的制作工艺,丰富对陕西建筑壁画的认识具有重要意义。     

THE ORIGIN AND GEOCHEMICAL CHARACTERIZATION OF RED OCHRES FROM THE TITO BUSTILLO AND MONTE CASTILLO CAVES (NORTHERN SPAIN)*

Ochres were the most common source materials for pigments used in Palaeolithic rock art paintings. This work analyses the petrographic and geochemical signatures of different ochre samples from outcrops inside Tito Bustillo Cave and the Monte Castillo Caves using the most common techniques (petrography, XRD, SEM–EDS and ICP–MS) in archaeological pigment characterization studies. The results obtained permit the identification and characterization of the different source ochre types and, furthermore, allow the establishment of mineralogical and geochemical proxies for the study of questions related to ochre characterization, formation processes and provenance.     

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。     

Polychromic structures and pigments in Guangyuan Thousand-Buddha Grotto of the Tang Dynasty (China)

This paper presents a multi-analytical study of the polychromy in the Guangyuan Thousand-Buddha Grotto. Samples taken from 15 locations in No. 512 and No. 689 caves are prepared as cross-sections for the analysis by optical microscopy (OM) and scanning electron microscopy coupled with backscattered electron imaging (SEM-BSE). The cross section analysis indicates that some paintings were repainted in the past. The chemical composition of each painting layer is obtained by scanning electron microscopy coupled with energy-dispersive X-ray analysis (SEM-EDX). The main pigments for 15 samples including green, red, blue, white and black paint layers, are identified by the combination of polarized light microscopy (PLM), Fourier Transform infrared spectrum (FT-IR), Raman spectroscopy (RS) and X-ray diffraction (XRD) analysis. The integrated analytical results reveal that the green pigments are malachite and atacamite; the red color is attributed to minium, hematite and cinnabar; the blue pigments are lazurite and organic blue materials; the white color is ascribed to anglesite and gypsum; and the black surface of polychrome is the accumulation of longtime smudging by folk burning incense in the devotional practice or the soot deposition resulting from burning bonfires in the caves. Some arsenic-containing pigment is detected in the green samples. This case study also demonstrates the advantages and the limitations of every analytical technique for the pigment identification, confirming the necessity of the integrated analytical techniques approach. The present results are not only useful to assist in the authenticity of the used pigment materials and history of the polychromic in the past, but also aimed at guiding the conservation scientists in taking into account materials and methods utilized in the past.     

Identification of PbO (BaO) faience from an early and middle Warring States period cemetery at Zhaitouhe,northern Shaanxi,China

Low‐temperature vitreous materials fluxed with lead (and barium) appeared in the early Warring States period (c.fifth century bce ) in ancient China. A range of lead vitreous products fluxed with the same agent, including faience/glass beads, glazed pottery and Chinese blue (purple) pigment, were developed subsequently. This study carries out scientific analysis of six vitreous beads unearthed from the Zhaitouhe cemetery site in northern Shaanxi dating to the early and middle Warring States period to investigate their chemical composition, microstructure and coloration. The lead (and barium) vitreous beads identified here are some of the earliest lead vitreous materials discovered in China so far, and therefore important for the study of the development of lead vitreous technologies in ancient China. This paper also points out that it is meaningful to evaluate the lead glass, glazed pottery and barium copper silicate pigments as a whole technological assemblage given their close relationships.     

THE CHARACTERIZATION OF PAINTS AND WATERPROOFING MATERIALS FROM THE SHIPWRECKS FOUND AT THE ARCHAEOLOGICAL SITE OF THE ETRUSCAN AND ROMAN HARBOUR OF PISA (ITALY)*

This work presents the results of a diagnostic survey on the shipwrecks from the archaeological site of the ancient harbour of San Rossore (Pisa, Italy). The original waterproofing, caulking and painting materials were characterized by Fourier transform infrared spectroscopy (FTIR), gas chromatography – mass spectrometry (GC–MS), energy‐dispersive X‐ray microanalysis (EDX) and X‐ray diffraction (XRD). The major constituents of the waterproofing and caulking materials detected on the planks were tricyclic abietanes showing a high degree of aromatization. These compounds are indicative of a pitch obtained from the wood of trees of the Pinaceae family. The analysis of the organic components of the paint samples revealed diterpenoid acids characteristic of Pinaceae resins together with linear long‐chain alcohols and fatty acids, highlighting the presence of beeswax. Noticeably, the characteristic odd carbon number alkanes that are normally present in beeswax were not detected. The EDX and XRD analyses showed that hematite, calcite, cerussite and kaolinite were employed as pigments to paint the ships’ hulls.     

The Tomb of the Three Brothers in Palmyra: The Use of Mimetite,A Rare Yellow Pigment,in A Rich Decoration

The wall paintings of the Tomb of the Three Brothers in Palmyra display a very rich Greco‐Roman iconography. The study of the painting reveals the use of a great variety of pigments, including Egyptian blue and an extremely rare bright yellow pigment, mimetite, of which no other traces are known for this period. This pigment was identified through the combined use of two methods of analysis, scanning electron microscopy associated with X‐ray microanalysis (SEM–EDS) and X‐ray micro‐diffraction (XRD). The varied chromatic palette used underlines the refinement and the particular care given to these decorations. Notable differences have been found between the pigments of the decorations of the arch and those used for the rest of the chamber.     

ARCHAEOLOGICAL,STYLISTIC AND SCIENTIFIC RESEARCH ON 11TH–13TH CENTURY AD PAINTED FRAGMENTS FROM THE SAN GIOVANNI BATTISTA CHURCH IN CEVIO (SWITZERLAND)

The painted fragments collected during the archaeological excavation campaign in the San Giovanni Battista church in Cevio represent a unique patrimony of Romanesque wall painting in Tessin, Switzerland, having a strong stylistic linkage with the Lombardic art of the same period. The archaeological and stylistic research allowed the fragments to be dated between the 11th and 13th centuries ad and to group them in three chronological phases. The scientific research (p‐XRF, OM, SEM–EDS, FTIR and XRD) was aimed at characterizing the pigments and the pictorial techniques used. Important changes occurred in terms of some pigments used during the 11th and 12th centuries: in particular, azurite was used to decorate the earlier wall paintings while lapis lazuli was used for the 12th‐century ones. During the second period, lead‐based pigments (lead white and minium) were introduced into the palette. The use of natural yellow and red ochres and green earth was common for the three periods. The fresco technique was generally used, except for the application of azurite and lead‐based pigments, where the a secco technique was adopted. The integrated research is a contribution to the knowledge of Romanesque art in the Insubric Region.     

The Source of Iron‐Oxide Pigments Used in Pecos River Style Rock Paints

The likely sources of iron‐oxide pigments used in prehistoric rock paintings in the Lower Pecos Archaeological Region were identified on the basis of chemical fingerprinting using LA–ICP–MS. The chemical signatures of 13 red rock paint samples collected from two south‐west Texas sites were compared with three potential source materials (ochre, siltstone and rhyolite), and two pigment cakes (crayons) that were excavated near the sampling sites. The significant chemical similarities between the paint and siltstones suggest that siltstone was used as the source of the colour. The overlapping chemical signatures for one of the pigment cakes and siltstone further suggests that some of the prehistoric people inhabiting the area 3000–4000 years ago had acquired the skills to extract iron oxide from siltstone and process it into paint pigments.     

ANALYTICAL CHARACTERIZATION OF ROMAN PLASTERS OF THE ‘DOMUS FARINI’ IN MODENA*

The paper refers to the analytical characterization of Roman painted plasters dating back to the second century ad . The following techniques were used: optical microscopy (OM), scanning electron microscopy (SEM–EDS), micro‐Raman and Fourier transform infrared spectroscopies (µ‐Raman and FT–IR), X‐ray diffraction (XRPD), colorimetry and thermal analyses (TG/DTA). The investigation analysed the chemical composition and structure of the plasters, the chemical composition of the pigment layers, the use of binders and any chemical alteration of pigments as well as deterioration of the samples. Stratigraphic analysis of plasters allowed identification of their individual components, which proved helpful in finding out more about the mural painting technique employed.     

MULTIANALYTICAL STUDY OF PALAEOLITHIC REINDEER ANTLER. DISCOVERY OF ANTLER TRACES IN LASCAUX PIGMENTS BY TEM*

Palaeolithic and modern reindeer antler were analysed using complementary techniques to evaluate the conservation state of bone material. X‐ray diffraction, FT‐IR spectroscopy, scanning electron microscopy (SEM–EDX) and transmission electron microscopy (TEM–EDX) as well as proton induced X‐ray and γ‐ray emission (PIXE–PIGE) at the particle accelerator AGLAE, C2RMF were applied. This study enabled us to define the chemical and structural features of ancient antler at the micro‐ and nanometre scale and compare them to those of other bone materials such as bone and ivory. Antler is richer in its organic fraction compared to bone and ivory. Its mineral fraction, carbonated hydroxylapatite, shows very specific crystal shapes at the nanometre scale. This specific property allowed us to recognize antler traces in pigment samples originating from rock art paintings in the Lascaux cave, Dordogne, southwestern France, Magdalenian period. Therefore, TEM–EDX is the technique of choice for characterizing antler traces in complex mixtures. In the paint material of Lascaux, antler seems most likely to be a pollutant introduced either by stirring the pigments in water with a piece of antler or by carving antler artefacts next to the preparation of paint material. However, it could eventually be used as a marker of paintings that were created contemporaneously.     

The Production of Lead–Tin Yellow at Merovingian Schleitheim (Switzerland)*

A Merovingian crucible fragment, with internally adhering yellow glass, and yellow glass beads of the same region and period were investigated by non‐destructive XRF, optical microscopy and SEM‐EDS. Although the microstructure and chemical composition of the yellow pigment (lead–tin yellow type II, ‘PbSnO₃’) are almost identical in both the beads and the crucible, in the latter the pigment occurs in a much higher concentration. However, the glass base in the beads and the crucible is very different, indicating that the beads were not manufactured directly from the crucible. Instead, the crucible most likely served to produce lead–tin yellow, which was subsequently mixed elsewhere with a colourless soda–lime glass to produce yellow glass beads.