Pamela Vandiver University of Arizona
Francesca Casadio The Art Institute of Chicago
Blythe McCarthy Smithsonian Institution
Robert H. Tykot University of South Florida
Jose Luis Ruvalcaba Sil Universidad Nacional Autonoma de Mexico
Y1: Archaeological Science
Monday PM, November 26, 2007
10:00 AM - Y1.1
Copper and Bronze Manufacture During the Third and Second Millennium B.C.E. at Godin Tepe, Iran.
Lesley Frame 1 Show Abstract
1 Materials Science and Engineering, University of Arizona, Tucson, Arizona, United States
Godin Tepe lies along the “High Road” leading from the Mesopotamian lowlands to the northern Iranian Plateau and beyond. This site acted as a center for the exchange of goods, transmission of ideas, and spread of technology. Therefore the technology and manufacturing methods represented by the artifacts at this site provide information regarding the methods used in this region of the Iranian Plateau. Materials analyzed from Godin Tepe include moulds, slag, crucibles, ore, and metal artifacts dating to the early third through late second millennium B.C.E. The production materials (moulds, slag, crucibles, and ore) were concentrated in only a few locations throughout the site, and they are indicative of small scale production. SEM and microprobe analyses have allowed the determination of solidification rates and temperatures reached during smelting and casting operations in antiquity, and XRD and lead isotope studies were used to identify possible ore sources. In addition, the analysis of approximately 60 metal artifacts (out of the two-hundred plus that were excavated) have contributed greatly to understanding the technology present during this time period. The results of this investigation support two significant conclusions. First, with the reconstruction of the production process, from the obtainment of raw materials to the dispersal of finished products, it is possible to re-examine the demands that small-scale production places on the exchange of raw materials and finished metal objects. Second, the metal artifacts from Godin Tepe represent a shift in technology from unintentional Cu-As alloys to pure Cu and intentional Cu-Sn alloys. Although this transition has been discussed by others, the well-stratified materials from Godin Tepe allow this shift in technology to be seen with better temporal resolution than before.
10:15 AM - Y1.2
Prehistoric Ceramics of Northern Afghanistan: Neolithic through the Iron Age.
Charles Kolb 1 Show Abstract
1 , National Endowment for the Humanities, Washington, District of Columbia, United States
Afghanistan, "Land of the Afghans," situated the crossroads of Eurasian commerce for nearly four millennia, was and is ethnically and linguistically diverse, a mosaic of cultures and languages. This diversity is exemplified in the north, where the Turkestan Plain was a conduit for the so-called Silk Route, a series of “roads” that connected far-flung towns and urban centers and facilitated the transfer of goods and services. My research involves the comparative analysis of archaeological ceramics from a series of archaeological sites excavated in northern Afghanistan in the 1960s by the late Louis Dupree and me. I served as the field director (1965-1967) and analyzed the ceramics excavated from six archaeological sites. These six sites were Aq Kupruk I, II, III, and IV in Balkh Province and Darra-i-Kur and Hazar Gusfand in Badakshan and Tarkar Provinces. Ten of the 72 ceramic types from the Aq Kupruk area have been published (Kolb 1977, 1983, 1989a) and none of the 53 wares from northeastern Afghanistan have been described. The majority of the Aq Kupruk materials are undecorated (plain ware) ceramics but there is a unique series of red-painted decorated ceramics (Red/Buff, numbered types 45 through 52) with early first millennium BCE designs but that date to the BCE-CE period. The results of ceramic typological, macroscopic, binocular and petrographic microscopy (thin-section analysis and point counting) are reported.
11:00 AM - **Y1.3
Microstructural Evidence of Reconstituted Limestone Blocks in the Pyramids of Egypt.
Michel Barsoum 1 , Aaron Sakulich 1 , Adrish Ganguly 1 , Giles Hug 2 Show Abstract
1 , Drexel University, Philadelphia, Pennsylvania, United States, 2 2LEM , ONERA-CNRS, , Châtillon France
How the Great Pyramids of Egypt were built has remained an enduring mystery. In the mid-Eighties Davidovits1 proposed that the pyramids were cast in situ using granular limestone aggregate and an alkali alumino-silicate-based binder. Hard evidence for this idea, however, remained elusive. Using primarily scanning and transmission electron microscopy, we compared a number of pyramid limestone samples to six different limestone samples from their vicinity. The pyramid samples contained microconstituents, µc’s, with appreciable amounts of Si in combination with elements, such as Ca and Mg, in ratios that do not exist in any of the potential limestone sources. The intimate proximity of the µc’s suggests that at some time these elements had been together in a solution. Furthermore, between the natural limestone aggregates, the µc's with chemistries reminiscent of calcite and dolomite - not known to hydrate in nature - were hydrated. The ubiquity of Si and the presence of 60 nm silica spheres in some of the micrographs strongly suggest that the solution was basic. TEM confirmed that some of these Si-containing µc’s were either amorphous or nanocrystalline, which is consistent with a relatively rapid precipitation reaction. The sophistication and endurance of this ancient concrete technology is simply astounding; its implications to today's world will be discussed.
11:30 AM - Y1.4
Analysis of Old Clothes for the Historical Research of East Asian Culture.
Ari Ide-Ektessabi 1 , Tomoko Katayama 2 , Kazuki Funahashi 2 , Ryoichi Nishimura 2 Show Abstract
1 International Innovation Center, Kyoto University, Kyoto Japan, 2 Mechanical Engineering and Science, Kyoto University, Kyoto Japan
Clothes reflect the cultures of those who put them on. Therefore, in the field of the archaeology, human or historical science, analyzing the old clothes is important and meaningful. In this talk, we studied four pieces of old Mongolian clothes for the aid of the research of old Mongolian culture, furthermore, East Asian culture. Mongolia is a country located in East Asia. From 13th century to the 15th century, the Mongol Empire flourished there. Especially in the 13th, the power of the empire was tremendous and it conquered from north China to Iran, throughout continental Eurasia. During this period, the culture of Mongolia was expanded throughout the Asia and its influence lasted long. Therefore, the research of Mongolian culture is important not only for the historical science in Mongolia but also for that of East Asia.First of all, we treated AMS analysis to precise their age. Then, X-ray fluorescence using Synchrotron Radiation (SR-XRF) was carried out. XRF analysis has been applied to nondestructive trace element analysis and element distribution. Additionally, SR-XRF is possible to analyze trace elements in the air with high resolution and sensitivity because of the high brightness of synchrotron radiation. In this paper, SR-XRF (1mm size, energies 16KeV) was performed in each clothes. The measurement area was 20mm*20mm. After obtaining the spectrum map, we selected several main elements and elemental maps were obtained. The result of SR-XRF analysis showed that the clothes include several different elements such as Au, Cu, Fe, Ti, and Pb. We also produced high resolution images taken by Scanning Electron Microscope (SEM). Based on the whole acquired data, we discuss an aspect of the old Mongolian culture.
11:45 AM - Y1.5
Analysis of Modern and Ancient Artifacts for the Presence of Corn Beer; Dynamic Headspace Testing of Pottery Sherds from Mexico and New Mexico.
Ted Borek 1 , Michael Keenan 1 , Glenna Dean 2 Show Abstract
1 , Sandia National Laboratories, Albuquerque, New Mexico, United States, 2 , Archeobotanical Services, Inc., Abiquiu, New Mexico, United States
A large volume-headspace apparatus that permits the heating of pottery fragments for direct analysis by gas chromatography/mass spectrometry is described here. A series of fermented-corn beverages were produced in modern clay pots and the pots were sampled to develop organic-species profiles for comparison with fragments of ancient pottery. Brewing pots from the Tarahumara of northern Mexico, a tribe that regularly uses corn kernels to ferment a weak beer, were also examined for volatile residues and organic-species profiles were generated. Finally, organic species were generated from ancient potsherds from an archaeological site and compared with the modern spectra. The datasets yielded similar organic species, many of which were identified by computer matching of the resulting mass spectra with the NIST mass spectral library. Additional analyses are now underway to highlight patterns of organic species common to all the spectra. This presentation demonstrates the utility of GC/MS for detecting fermentation residues in the fabric of unglazed archaeological ceramics after centuries of burial. This, in turn, opens unexpected new doors for understanding the human past by means of GC/MS analyses.
12:00 PM - Y1.6
Obsidian Subsources Utilized at Sites in Southern Sardinia (Italy).
Robert Tykot 1 , Michael Glascock 2 , R. Speakman 3 , Enrico Atzeni 4 Show Abstract
1 Anthropology, University of South Florida, Tampa, Florida, United States, 2 , University of Missouri, Columbia, Missouri, United States, 3 , Smithsonian Institution, Washington, District of Columbia, United States, 4 , Università di Cagliari, Cagliari Italy
While geochemical analysis of obsidian artifacts is now widely applied around the world, both new instrumental methods and new research questions continue to be applied in archaeology. In the Mediterranean, many analytical methods (including OES, AAS, XRF, INAA, SEM, Fission-Track Dating, Electron Microprobe, Magnetic Properties, LA-ICP-MS, and PIXE) have been employed and proven successful in distinguishing all of the island sources. Yet the number of studies done on significant numbers of archaeological artifacts is still quite modest, with little done in certain geographic regions and/or cultural time periods. In this study, results are presented from the virtually non-destructive, LA-ICP-MS multi-element analysis of 95 carefully selected obsidian artifacts from four neolithic period (ca. 6000-3000 BC) sites (Cuccuru Ibba-Capoterra, San Gemiliano-Sestu, Is Solinas-Masainas, and Su Carroppu-Sirri) in southwestern Sardinia. Along with physical/visual assessment of about 600 obsidian artifacts from an additional 6 sites, these analyses add significantly to the early study by Michels et al. (1984) on 53 artifacts from 5 other sites using AAS, and expand the results more recently obtained for Su Carroppu by Lugliè et al. (2007).The LA-ICP-MS results reported here provide geological attributions to specific obsidian subsources in the Monte Arci complex in west-central Sardinia (Tykot 1997). Previous studies have already demonstrated the importance of attributing artifacts to specific subsources, in part because they vary in physical and visual features, accessibility, and quantity available in particular locations, and because the relative usage of the different subsources changed over time (Tykot 1996; 2002a,b,c). The patterns of exploitation revealed in this study support a down-the-line model of obsidian trade during the neolithic period, but with chronological changes that are best explained by increased socioeconomic complexity. These interpretations are compared with other archaeological data for southern Sardinia, and with those based on obsidian studies done in central-northern Sardinia, Corsica, and elsewhere in the central Mediterranean.ReferencesLugliè, C., Le Bourdonnec, F.-X., Poupeau, G., Atzeni, E., Dubernet, S., Moretto, P., Serani, L. 2007. J. Archaeological Science 34: 428-439.Michels, J. W., Atzeni, E., Tsong, I.S.T., Smith, G.A. 1984. In M.S. Balmuth & R.J. Rowland, Jr. (eds.), Studies in Sardinian Archaeology, 83-144. University of Michigan Press.Tykot, R.H. 1996. J. Mediterranean Archaeology 9: 39-82.Tykot, R.H. 1997. J. Archaeological Science 24: 467-479.Tykot, R.H. 2002a. Accounts of Chemical Research 35:618-627. Tykot, R.H. 2002b. American Chemical Society Symposium Series 831, 169-184.Tykot, R.H. 2002c. Materials Research Society Proceedings 712: 143-157.
Y2: Ancient Technology
Monday PM, November 26, 2007
2:30 PM - Y2.1
The Reduction Welding Technique used in Pre-Columbian Times: Evidences from a Silver Ring from Incallajta, Bolivia, Studied by Microscopy, SEM, EDAX, FAAS and PIXE.
Luis Torres Montes 2 , Jose Luis Ruvalcaba 1 , Demetrio Mendoza Anaya 3 , Maria de los Angeles Munos Collazo 5 , Francisca Franco Velazquez 4 , Francisco Sandoval Perez 4 Show Abstract
2 , Instituto de Investigaciones Antropologicas, Universidad Nacional Autonoma de Mexico, Mexico, DF, Mexico, 1 , Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Mexico, DF, Mexico, 3 , Instituto Nacional de Investigaciones Nucleares, Salazar, Edo. de Mexico, Mexico, 5 , Museo Arqueológico de la UMSS, Cochabamba Bolivia, Plurinational State of, 4 Depto. Materiales, Universidad Autónoma Metropolitana-Azcapotzalco, Mexico, DF, Mexico
From Etruscan ages, and later in the Byzantine period and Middle Ages, jewelry and other gold objects were decorated with a technique know as granulation: Small gold spheres were welded over the surface of the metallic artifact, up to 900 beads by square centimeter. The technique was forgotten and when the goldsmiths treated to reproduce the process, a plaque of gold was formed over the surface of the object because the small beads fused when heat was applied to weld them. This technique was rediscovered in the 1940’s by Litteldale at the British Museum. In the 20th Century some jewel fakes with this technique started to appear and later a patent was register. The reduction welding technique consists of a mixture of an organic adhesive with a copper salt, used to glue the beads to the body of the object and then it was heated with a blow pipe. The organic adhesive was burnt and of the copper salt was reduced, depositing pure copper that welded the beads to the body of the jewel, without fusing them. On the other hand, a silver ring from Incallajta, Cochabamba, Bolivia, was recovered from archaeological excavations. It is a thin plaque of silver that in one end has two small nails that protrude to the side, the plaque is bended to form the ring and the sheet is fixed by folding the nails over the other end of the ring. Two small wires bended to produce an infinity sing or to form an eight number were soldered over the surface of the ring and four turquoise beads were incrusted inside the four hollows. The EDX and PIXE results of the four beads proved that the beads were made of turquoise.Examinations with the optical microscope indicated that the two wires were apparently soldered to the body of the ring by the reduce welding, a technique not observed before in Pre-Columbian metallurgy. To prove this theory, the ring was analyzed with SEM and EDX as well as external beam PIXE, showing that certainly the copper content in the place were the welding was produced was higher than in any other part of the ring. To verify if the analysis were in accordance with this technique, these studies were reproduced in two silver objects from Indonesia, were the reduction welding technique was used, so that the same analyses were performed to determine similarities and differences among the silver items. In one of the silver objects, a cross section was prepared to obtain the elemental composition of the soldered area and to have a better idea of the reduction welding technique used in the manufacturing of the silver ring. Results are discussed.
2:45 PM - Y2.2
``For Whom the Bell Tolls" Mexican Copper Bells from the Templo Mayor Offerings: Analysis of the Production Process and its Cultural Context.
Niklas Schulze 1 Show Abstract
1 FFyL-IIA, Universidad Nacional Autónoma de México, Mexico City Mexico
3:00 PM - **Y2.3
Preserving Intangible Aspects of Cultural Materials: Bon-po Ritual Crafts of Amdo, Eastern Tibet.
Chandra Reedy 1 Show Abstract
1 Center for Historic Architecture and Design, University of Delaware, Newark, Delaware, United States
Ancient and historic products of past technologies exist in the form of material culture and archaeological finds, available for materials analysis. Technical studies and analytical work, coupled with the study of historical texts and archival documents, can help in reconstructing past technologies. However, the act of making an object is, by its very nature, also an intangible part of human heritage. In addition to raw materials and fabrication processes, which are more amenable to understanding through laboratory analysis, production of material culture may be accompanied by specific rituals, social behaviors and relationships, music, knowledge gained from oral histories, meanings, intents, beliefs, and reasoning processes. For ancient objects, gaining access to these intangible aspects of cultural heritage may be extremely difficult, if not impossible. However, there are many societies where traditional crafts are still produced within a context where the intangible aspects can still be recorded. Yet, these opportunities are disappearing at an alarming rate as development and globalization rapidly overtake more and more traditional communities. Documenting the intangible data in conjunction with materials analysis can promote fuller understanding of the objects themselves, and aid long-term preservation of both the objects and the processes used to make them. Examples are drawn from fieldwork conducted at a Bon-po monastery (Seling Gonpa) and nearby villages in the Amdo region of eastern Tibet (in Sichuan, China). Bon-po is the native, pre-Buddhist religion of Tibet. Although Buddhism is now the most widely-practiced religion in Tibet, Bon-po communities remain active, especially in eastern Tibet. The production and use of Bon-po ritual crafts are strongly rooted in a complex web of intangible relationships, behaviors, meanings, purposes, and beliefs. The discussion presented here will focus primarily on two ritual craft traditions, barley-dough sculptures (torma) and votive clay objects (tsha-tshas). Both tangible and intangible aspects of a variety of processes will be highlighted, such as deciding to make an object, choosing when to make it and in what form, selecting and collecting the raw materials, preparing raw materials, fabricating the object, selecting who will be involved in fabrication steps, choosing where to place the finished object, and deciding whether an object will be preserved for the long term or will be considered only temporary. The results of this research will be placed within the context of larger theoretical issues regarding documentation and preservation of intangible elements of cultural heritage as part of the study of materials and technological processes.
4:00 PM - Y2.4
Replications of Critical Technological Processes and the Use of Replicates as Characterization Standards: An Experiment in Undergraduate Education.
Pamela Vandiver 1 , Heather Raftery 2 , Stephanie Radcliffe 2 Show Abstract
1 Department of Materials Science & Engineering, University of Arizona, Tucson, Arizona, United States, 2 Department of Anthropology, University of Arizona, Tucson, Arizona, United States
An engineering, historical and socio-cultural approach to the study of ancient technologies at the undergraduate level is enhanced by hands-on projects. Case studies include establishing the compositional and firing parameters for Egyptian blue and Maya blue pigments, Greek slip glazes and Peruvian Moche pottery. Characterizing processing parameters for an impermeable coating on lime plaster church roofs in northwestern Mexico, making a mock-up to establish technique prior to x-raying an encased statue. Examples will be presented of some experiments that are suitable for a lecture class, for a lab class, and of some that are continued as independent studies.
4:15 PM - **Y2.5
Reassessing Bronze Age Manufacturing Technologies at Nuzi.
Andrew Shortland 2 , Katherine Eremin 1 , Susanna Kirk 2 , James Armstrong 3 Show Abstract
2 Centre for Archaeological and Forensic Analysis, Department of Materials and Medical Sciences, Cranfield University, Shrivenham, Wiltshire, United Kingdom, 1 Straus Center for Conservation, Harvard University Art Museums, Cambridge, Massachusetts, United States, 3 Semitic Museum, Harvard University, Cambridge, Massachusetts, United States
The Hurrian city of Nuzi, in modern Iraq, was an important site during the Mesopotamian Bronze Age. Excavations in the late 20s and early 30s yielded a large and important assemblage of glass and other vitreous materials and smaller but significant assemblages of metals and ceramics. The vitreous materials were dominated by beads, with tens of thousands recovered, but other artefacts, including decorated glass vessel fragments, molded figurines and amulets, were also found. Many ceramics are glazed and include figurines and architectural wall nails, whilst the metals include jewellery and armor. Although the vitreous materials have been widely studied in the past, the other assemblages have received little attention. A recent study indicated the presence of brass and dirty copper rather than the expected bronze but was limited to a few objects and did not investigate the proportions of the different alloys. Recent analyses of the glass highlighted compositional differences between Egyptian and Mesopotamian glass and attempted to link these to the raw materials used. The lack of significant tin or zinc in glasses colored with copper was interesting given the presence of brass and the apparent scarcity of bronze in the metals. The current study involves reassessment of the entire assemblage, concentrating initially on the vitreous materials, glazes and metals. Portable non-destructive x-ray fluorescence (XRF) analyses of the vitreous materials and glazes can identify the colorants even in heavily deteriorated examples with little indication of the original color or even material, and allow the state of preservation of the artifacts to be assessed. Many beads which do not currently appear vitreous were originally glass and that red, yellow and white glasses are more common the current surface appearance suggests. Variations in preservation across the site are being examined. Selected beads and vessels were sampled to obtain more accurate compositional data of the pristine and altered glass by scanning electron microscopy with energy and wavelength dispersive analysis (SEM-EDS-WDS). The structural modifications and phase transitions from alteration are being investigated by x-ray diffraction (XRD) and Raman spectroscopy. Unique beads which cannot be sampled are examined by controlled pressure SEM-EDS. Similar CP-SEM analyses of sampled beads and comparison of results from different techniques, allows improved interpretation of non-destructive results. Portable non-destructive XRF analyses of the metals can identify the different alloy types despite significant corrosion and hence assess the proportion of different alloys in the assemblage. Full characterization of the assemblages allows investigation of relationships between different manufacturing technologies and the raw materials used.
4:45 PM - **Y2.6
Characterization of Coral Red Slips on Greek Attic Pottery.
Marc Walton 1 , Karen Trentelman 1 , Eric Doehne 1 , Giacomo Chiari 1 , Jeffrey Maish 1 , Alex Buxbaum 2 Show Abstract
1 , Getty Conservation Institute, Los Angeles, California, United States, 2 , FEI Company, Hillsboro, Oregon, United States
Ancient Greek vase painting with clay slips (referred to as black and red “glosses”) had become a very sophisticated craft by the 6th century B.C. It has been shown through replication experiments of black glosses, that the ceramics were efficiently fired in a single firing that was stepped through three successive and controlled environmental stages: oxidation, reduction, and oxidation again. Oxidative kiln atmospheres were obtained by means of an updraft kiln with an open flue. The reductive atmosphere was achieved by adding organic matter (green plants, leaves, etc.) to the kiln chamber (with the flue closed) that would combust and thus deplete the kiln of available oxygen (O2) through the formation of carbon dioxide (CO2). The result of this firing sequence was pottery that was possessed detailed and high contrast drawing based on a limited palette of slip colors (i.e., red and black). Surprisingly there have been only a handful of studies that have reported quantitative analyses of the composition of black gloss, and even fewer that have described the composition of the red gloss (commonly called ‘coral red’) . It is this latter, understudied coral red that is the primary focus of this study. This paper will describe the material analysis of 13 fragments/vessels containing both coral red and black gloss. The samples were examined using scanning electron microscopy (SEM and FIB/STEM) with energy dispersive x-ray spectroscopy (EDS). The aim of the study was to provide a thorough characterization of Ancient Greek coral red and to compare this red material to black glosses. Comparison of the coral red and black glosses revealed two compositional groupings, suggesting the existence of two chemically distinct types of coral red material: in one the red was found to be compositionally similar to the black glosses, whereas in the other the red showed more significant chemical differences, such as higher calcium, in comparison to the black. Scanning transmission electron microscopy (STEM) was subsequently employed to determine whether differences in the microstructure could also be observed. Black glosses were found to be glassy with little porosity, while both types of red contained approximately 20% porosity, with individual clay grains readily distinguishable from one another. Interestingly, no microstructural differences could be observed by STEM between the two different compositional groupings of red.The existence of two chemically distinct reds – otherwise identical in color and texture – suggests that there was more than one source of clay available to the Ancient Greek potters for producing red. Based on the compositional results several hypotheses will be presented as to how Ancient Greek pottery was fired and the likelihood that both reds came from clay sources with unique mineralogical properties will be discussed.
5:15 PM - Y2.7
Thermal Expansion and Deformation in Ancient Chinese Bronze Castings.
Michelle Taube 1 , Blythe McCarthy 1 Show Abstract
1 Dept of Conservation and Scientific Research, Freer Gallery of Art and Arthur M. Sackler Gallery, Washington, District of Columbia, United States
Ancient Chinese bronze vessels from the Shang to Zhou dynasties (c. 1500 - 221 BCE) were cast using piece molds. Several large vessel shapes, especially those with legs, have been found to be made in several steps with the vessel body cast onto previously-made legs or other appendages. In this situation the molten metal contacts and must attach to the solid pieces from the first casting. Similar interfaces are found at solid metal mold spacers or chaplets used in the casting process. Previous researchers showed that the casting can exhibit concentration gradients and evidence of slip in the regions around these interfaces. In this work, we studied the thermal expansion of the bronze at cast-on joints in ancient Chinese bronzes using thermomechanical analysis (TMA). The results are compared with those from several standard lead-tin bronze alloys.
Y3: Poster Session
Tuesday AM, November 27, 2007
Exhibition Hall D (Hynes)
9:00 PM - Y3.1
The Relation between the Fine Structural Change and Color Fading in the Natural Mineral Pigments of the Cultural Properties.
Ryoichi Nishimura 1 , Ari Ide-Ektessabi 1 Show Abstract
1 Department of Mechanical Engineering and Science, Graduate school of Engineering, Kyoto University, Yoshidahonmachi Japan
Many old Asian paintings have been drawn with natural mineral pigments. The discoloring mechanism of these pigments has been a real concern for the characterization, restoration and preservation of the ancient cultural properties. The authors expect that the color fading is deeply related with the chemical composition and the fine structural change of the major elements. Therefore the purpose of this paper is to make clear the relation between the fine structural change and color fading. We analyzed several representative pigments of Japan, including copper carbonate hydroxide pigments (blue verditer and green verditer, ”gunjo” and “ryokusho” called in Japanese) by x-ray fluorescence analysis (XRF) and x-ray absorption fine structure (XAFS). In order to examine the deterioration of pigments, some of them were exposed in the highly-heated condition. In addition, the spectral reflectivity data are also collected on spectrophotometer system . Here we propose to compare the results obtained from XRF and XAFS with the spectral reflectivity data. The results demonstrate that the chemical composition and the fine structural change can provide valuable information for revealing the discoloring mechanism, which would then lead to the original color estimation of the ancient cultural properties.
9:00 PM - Y3.4
Painted Decoration Studies in a Fourth Century BC Vergina Tomb.
Eleni Pavlidou 1 Show Abstract
1 Physics, Aristotle University of Thessaloniki, Thessaloniki Greece
E. Pavlidou (1), A. Kyriakou(2), E. Mirtsou(3), L. Anastasiou(1), T. Zorba(1), K. M. Paraskevopoulos(1)(1) Physics Department,( 2) Faculty of History & Archaeology,Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece (3) Archeological Museum of Thessaloniki, 54646 Thessaloniki, Greece. AbstractAegae, the first capital of the Macedonians, in Northern Greece, is being excavated since 1938. The most impressive finds come from the unlooted tombs of the Great Tumulus, where the grave of Philip II, father of Alexander the Great, was discovered. Not far from the Great Tumulus, in the “Tumuli cemetery”, the most ancient part of the graveyard (1000-700 B.C.), recent excavations brought to light three looted graves dated in the mid-fourth century B.C., with very interesting finds such as weapons, gilded wreaths, pieces of jewelry, remains of decoration of wooden furniture, ceramic vases broken in small pieces and wall paintings. This paper describes studies carried out on the binding and the painting materials used for the decoration of the above wall paintings and ceramic vases. The characterization was performed through Optical Microscopy, Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Microscopy (SEM-EDS). It was found that the fresco technique was used, while all the pigments were identified. The results are discussed and related with other findings in that period in the Greek area. Presentation preference: Poster
9:00 PM - Y3.5
On the Restoration of the 18th Century St. Athanasius Church in Moschopolis (Albania): Paint Materials Studies.
Eleni Pavlidou 1 , T. Zorba 1 , Konstantinos Paraskevopoulos 1 Show Abstract
1 Physics, Aristotle University of Thessaloniki, Thessaloniki Greece
In this paper are presented the studies of the paint materials and the technique used in 18th century wall paintings, originated from the orthodox church of St Athanasius, in the city of Maschopolis, a flourishing economical and cultural center, in Albania. The church was painted in 1745 by Konstantinos and Athanasios Zografi, and during the last years, restoration activities are being performed at the church. Samples that included plasters and pigments of different colors were collected from important points of the wall paintings. Additionally, as some parts of the wall-paintings were over-painted, the analysis was extended to the compositional characterization of these areas. The identification of the used materials was done by using complementary analytical methods such as Optical Microscopy, Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM-EDS) and X-ray fluorescence (TXRF). The presence of calcite in almost all the pigments is indicative for the use of the fresco technique at the studied areas, while the detection of gypsum and calcium oxalate, indicates an environmental degradation along with a biodegradation. Common pigments used in this area at 15-16th centuries, such as cinnabar, green earth, manganese oxide, carbon black and calcite were identified.
9:00 PM - Y3.6
Archeometallurgical Study of Brazilian Colonial Objects.
Guadalupe Campos 1 , Guillermo Solorzano 1 , Marc Aucouturier 2 Show Abstract
1 Department of Materials Science and Metallurgy, Pontificia Universidade Catolica - PUC-Rio, Rio de Janeiro, RJ, Brazil, 2 , Musée du Louvre, CNRS, Paris France
This work undertakes an archaeometallurgical study of ferrous and non-ferrous artifacts recovered from historical sites of Rio de Janeiro. The experimental research developed an analytical methodology based on destructive techniques, such as Optical Microscopy (OM), Scanning Electronic Microscopy (SEM) and Transmission Electronic Microscopy (TEM); as well as non-destructive techniques, namely X-Ray Fluorescence (XRF) and Particle Induction X-Ray Emission (PIXE). These artifacts were analyzed in order to characterize their composition, structure and elaboration/processing methods. There are six artifacts with non-ferrous metallic nature and one with a ferrous metallic nature. The ferrous metallic nature was a hoe. The microstructure characteristics are related to the usage of this object at the time, and indicate that the hoe could have been made in Brazil by African slaves. The analysis of hoe indicates that it waselaborated from puddle iron and that it had been processed by foundry and forging. The rosary, one of the non-ferrous artifacts, is formed by single-phase brass riche in copper; and according to historical research it is of European origin, deriving from pyrite ore. The medals are also of European origin and are based on a brass. Historically one can deduce that they are dated from the 18th century. The two coins from the Rochedo site most probably came from distinct sources, as validated by the chemical analysis. However, the chemical composition of the 1821 coins in close to that of the 40 Réis coin. The present investigation has shown the importance of a systematic methodology to characterize ancient objects combining both destructive and non-destructive techniques.
9:00 PM - Y3.7
Deciphering the Construction History of the 12th Century Ziče Charterhouse (Slovenia) through the Study of Mortars and Plasters.
Elena Basso 1 , Federico Caro 1 , Fortina Consuelo 1 , Viviana Guidetti 1 , Bruno Messiga 1 , Maria Pia Riccardi 2 , Mateja Golez 3 , Alenka Mauko 3 , Ana Mladenovic 3 , Bogdan Badovinac 1 Show Abstract
1 Earth Science Department, University, Pavia Italy, 2 , Institute for the Protection of Cultural heritage of Slovenia, Celje Slovenia, 3 , Slovenian National Building and Civil Engineering Institute, Ljubljana Slovenia
Pamela Vandiver University of Arizona
Francesca Casadio The Art Institute of Chicago
Blythe McCarthy Smithsonian Institution
Robert H. Tykot University of South Florida
Jose Luis Ruvalcaba Sil Universidad Nacional Autonoma de Mexico
Y4: Conservation Science I
Jose Luis Ruvalcaba
Tuesday AM, November 27, 2007
10:00 AM - Y4.1
Delamination of Oil Paints on Acrylic Grounds.
Yonah Maor 1 , Alison Murray 1 Show Abstract
1 Art Conservation, Queen's University, Kingston, Ontario, Canada
Since the 1950s many artists have been painting on canvases primed with acrylic grounds. The acrylic ground is used not only under acrylic paint but also beneath oil or alkyd paints. Normally, this is considered safe practice; however, there have been cases of severe delamination of the paint layer from the acrylic ground. Some paintings have even been destroyed. This research examines a set of samples prepared in 1999 by Marion Mecklenburg at the Smithsonian Museum Conservation Institute. The samples consist of oil and alkyd paints over different acrylic grounds. As of this date some of the samples containing oil paints are delaminating. The general methodology chosen was to characterize the samples as completely as possible in order to find out what the delaminating samples have in common. More specifically, a number of theories regarding the cause of the delamination are being tested. As the bond between the oil and acrylic layer is of a mechanical nature only, the fact that oil paints become much stiffer with age while acrylics remain more ductile can be quite significant. As well, zinc is known to inhibit the drying of oil paints, allowing the oxygen to penetrate further into the paint layer, ultimately making it drier throughout and more brittle. The zinc content in the paints was examined by x-ray fluorescence (XRF) and inductively coupled plasma (ICP). Initial results show a correlation: the greater the amount of zinc in the paint, the greater the number of samples delaminating. Another possible factor is the surfactants in the acrylic layer; these are known to migrate to the surface and may thus create a “release layer”. Previous work by Bronwyn Ormsby, at Tate, indicates that the composition of the acrylic copolymer may influence the surfactant build up. The binding media of both the ground and the paint layers can be characterized by pyrolysis-gas chromatography-mass spectroscopy (Py-GC/MS). The Py-GC/MS results show any correlation between the type of binder and the delaminating samples. Matrix-assisted laser desorption/ionization (MALDI) with mass spectroscopy has been used to identify the surfactants on the surface of acrylic paints. Applying MALDI/MS to aqueous extractions from the surface of the acrylic grounds may allow us to determine if the surfactants are a factor in the delamination process. The last factor that will be examined is the texture of the acrylic grounds. If the surface is too smooth or glossy, the oil paint cannot interlock properly with the ground and vibrations could cause delamination. A simple test with a gloss meter will give an indication of texture. If necessary, atomic force microscopy (AFM) will be used to allow a closer look at the surface texture. Since delamination of the paint and ground is quite rare, it probably occurs only when certain factors combine. Determining the cause of the delamination may lead to identifying way to prevent, or at least slow down, this process.
10:15 AM - Y4.2
Controlling Crystallization Pressure Through Surface Modification of Stone.
Megan McNall 1 , John Valenza 2 1 , Melanie Webb 1 , Stephen Garofalini 3 , George Scherer 1 Show Abstract
1 Civil & Env Eng, Princeton University, Princeton, New Jersey, United States, 2 , Schlumberger-Doll Research, Cambridge, Massachusetts, United States, 3 Mat. Sci. & Eng., Rutgers University, Piscataway, New Jersey, United States
When salts crystallize in the pores of stone, a film of solution remains between the salt and the surrounding mineral surfaces. It is this film, which is sustained by disjoining forces (repulsive pressure) between the incompatible crystals, that permits ions to diffuse to the surface of the salt, so that it can continue to grow and exert pressure on the stone. To attack the cause of salt damage to stone, it is necessary to reduce or eliminate the disjoining forces, so that the salt comes directly into contact with the pore wall and growth stops. Houck et al. demonstrated that a thin film of polyacrylic acid (PAA) influences the growth pattern of sodium sulfate, and that stone treated with PAA is more resistant to damage in the sulfate test. In this work, we use a novel test that provides direct evidence for the reduction of disjoining pressure by PAA. A plate of stone is glued to a glass plate and the stone is impregnated with thenardite, then water is introduced; as the water invades, mirabilite precipitates and exerts pressure on the stone. As crystallization pressure makes the stone expand, the composite warps; the stress generated by the salt can be quantified by measuring the deflection of plate. Large deflections are observed when bare stone is used, but stone treated with PAA shows very little deflection, indicating that the crystallization pressure has been reduced. Tests using Indiana limestone show that the stress in the treated stones falls below the tensile strength, whereas the untreated stones experience larger stresses (which results in severe damage after one cycle of crystallization). This paper will discuss the effectiveness of the coating: the amount needed, its distribution within the pores, and the durability of the coating during wetting/drying cycles.To account for the presence of repulsive (disjoining) forces between the salt and mineral surfaces, molecular dynamics (MD) is used to examine the structure and energy of the system consisting of a crystal of NaCl separated from a crystal of quartz by a film of solution about 1 nm thick. Simulations indicate that the force between the crystals changes from attraction to repulsion as the distance between them decreases. The transition point is at a greater distance when the liquid is a saturated solution than when it is pure water, indicating that the solvated ions contribute to the repulsion. Ordering of the ions and interactions with the solid surfaces are also observed. The influence of these factors on crystallization pressure will be discussed.
11:00 AM - **Y4.3
Predicting Efflorescence and Subflorescences of Salts.
Rosa Espinosa 1 , Lutz Franke 1 , Gernod Deckelmann 1 Show Abstract
1 , Hamburg University of Technology, Hamburg Germany
Crystallization of salts is a common cause of damage in porous building materials. Understanding of the crystallization mechanism of these salts is important in order to prevent or avoid the problem. Subflorescence of salts can induce scaling and cracking, while efflorescence does not generally affect the coherence and endurance of the building materials. In this paper, we deal with the crystallization of two salts, sodium sulphate and sodium chloride, in a brick. Samples impregnated with the salt solutions are dried under controlled conditions. The results reveal quite different crystallization behavior of the two salts. While sodium chloride tends to effloresce, sodium sulphate subfloresces in a thin layer under the surface and scaling takes place.To explain this, a simulation of the experiments is carried out using a mathematical model. The ion transport is computed by means of the Nernst-Plank-model coupled with the salt crystallization. Crystallization kinetics are computed as a function of the supersaturation ratio of the solution . Further, it is assumed that the stress is induced by the crystallization pressure of the confined crystals in the pores . The salt crystals are distributed in the pore network to calculate the stress due to crystallization . Finally, the pore filling with crystals induces a change of the transport coefficients of the solution. This coupled model was tested previously [4,5]. According to this model, the solution must be supersaturated for crystallization to start, which is induced by evaporation. Indeed, the main reason for the different behavior of these salts is the supersaturation necessary for nucleation of crystals. Thus, the sodium sulphate solution is prone to be more supersaturated than sodium chloride. The simulation shows that the solution transport, which depends on salt, porosity and climatic conditions affects the position of the crystallization front. The crystallization pressure induced by the crystallization of mirabilite is much higher because of the reached higher supersaturation. Indeed, considering supersaturation ratio and solution transport, it is possible to simulate the different crystallization behaviour observed in the experiment. 1.Espinosa R. et al.: Phase changes of salts in porous materials. Construction and Building Materials, Elsevier, 2007 in press.2.Scherer, G.: Stress from crystallization of salt, Cement and Concrete Research 34 (2004) 1613-16243.Espinosa R. et. al.: Model for the mechanical stress due to the salt crystallization in porous materials. Construction and Building Materials, Elsevier, 2007 in press. 4.Espinosa R. et. al: Damage due to phase changes of salts in porous materials. Proc. of 5th Int. Essen Workshop: Transport in Concrete, 2007. 5.Franke, L. et al.: Cesa und Astra-two program systems for cement and salt chemistry and the prediction of corrosion processes in concrete. Proc. of 5th Int. Essen Workshop: Transport in Concrete, 2007.
11:30 AM - **Y4.4
Self-assembled Silver Nanoparticle Films as Gas Sensors in Oddy Tests.
Rui Chen 1 , Laura Moussa 2 , Hannah Morris 1 , Paul Whitmore 1 Show Abstract
1 Art Conservation Research Center, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States, 2 Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States
It has been realized that air pollutants in a museum environment and gases emitted from storage and display materials can cause or accelerate the degradation of materials, particularly metals, used to make works of art. A general and practical method widely applied in museums to evaluate the safety of storage and display materials is the Oddy test, which is performed by enclosing a sample of the material of interest along with metal coupons (usually of silver, copper, and lead) in a 100% RH environment. The test system is incubated at 60°C for 28 days, after which the coupons are visually examined for evidence of corrosion from offgassing emissions from the test material. While very practical and useful, the Oddy test is time-consuming and cannot easily be evaluated to quantify the extent of corrosion that has occurred on the metal coupons. Developments in nanotechnology in recent years have inspired us to explore the potential of silver nanoparticle assemblies as sensors to replace the silver coupon in the Oddy test. As the size of a silver particle is decreased to the nanometer level, the high surface area of the particles should allow very rapid reaction with the emitted pollutants (usually sulfur gases). Furthermore, silver nanoparticles exhibit a significant optical absorption in the visible region of the spectrum due to the surface plasmon resonance (SPR). This property endows silver nanoparticles with a variety of colors depending on particle size and shape. Quantitative evaluation of the extent of reaction should thus be possible by measuring the changes in the visible absorption spectrum of the nanoparticles.We report here the preparation and performance of a silver nanoparticle-based sensor for use in Oddy tests. Spherical Ag nanoparticles (~ 30 nm diameter, SPR absorption at 420 nm) and triangular nanoprisms (~ 30 nm width, SPR absorption at 700 nm) were synthesized. Each of these types of Ag nanoparticles (NPs) was self-assembled into films on glass slides with polyethylenimine. UV-vis spectrophotometry was employed to measure the SPR intensity of the Ag NP films in order to evaluate the extent of reaction. It was observed that the Ag NP films were quite stable under Oddy test conditions in a blank test, with no change in the SPR absorptions after a month at 60°C and 100% RH. The sensitivity of Ag NP films to H2S gas emitted from wool fabrics in the Oddy test was investigated. UV-vis spectra taken after the Oddy tests showed the disappearance of the Ag NP SPR peak and the growth of the UV absorption due to Ag2S. SEM-EDX analysis confirmed that sulfur had been incorporated into the Ag NP film. By adjusting the NP density of the films, we are able to create Ag NP films that indicated H2S prior to visible tarnishing of a Ag coupon. In summary, our research demonstrates that Ag NP films can be used as sensitive, quantitative sensors to replace Ag coupons in the Oddy test system.
12:00 PM - **Y4.5
Thermal Volatilisation Analysis – A Novel Non-Destructive Technique for the Analysis of Conservation Artefacts.
James Lewicki 1 , John Liggat 1 , Lorraine Gibson 1 Show Abstract
1 Pure and Applied Chemistry, University of Strathclyde, Glasgow United Kingdom
Y5: Conservation Science II
Jose Luis Ruvalcaba
Tuesday PM, November 27, 2007
3:00 PM - **Y5.1
Focused-Ion Beam and Electron Microscopy Analysis of Corrosion of Lead-Tin Alloys: Applications to Conservation of Organ Pipes.
Catherine Oertel 1 , Shefford Baker 2 , Annika Niklasson 3 , Lars-Gunnar Johansson 3 , Jan-Erik Svensson 3 Show Abstract
1 Department of Chemistry and Biochemistry, Oberlin College, Oberlin, Ohio, United States, 2 Department of Materials Science and Engineering, Cornell University, Ithaca, New York, United States, 3 Department of Chemical and Biological Engineering, Chalmers University of Technology, Göteborg Sweden
Across Europe, lead-tin alloy organ pipes are suffering from atmospheric corrosion. This deterioration can eventually lead to cracks and holes, preventing the pipes from sounding. Organ pipes are found in compositions ranging from >99% Pb to >99% Sn. For very lead-rich (>99% Pb) pipes, organic acids emitted from the wood of organ cases have previously been identified as significant corrosive agents. In order to study the role of alloy composition in the susceptibility of pipes to organic acid attack, lead-tin alloys containing 0-10% Sn were exposed to acetic acid vapors in laboratory exposure studies. Corrosion rates were monitored gravimetrically, and corrosion product phases were identified using grazing incidence angle X-ray diffraction. In a new method, focused-ion beam (FIB) cross-sections were cut through corrosion sites, and SEM, EDX, and WDX were used to obtain detailed information about the morphology and chemical composition of the corrosion layers. The combination of FIB and SEM has made it possible to obtain depth information about these micron-scale layers, providing insight into the influence of acetic acid on alloys in the 0-10% Sn range.
3:30 PM - Y5.2
Evaluation of Fluorinated Protective Topcoats for Outdoor Metals.
Tami Lasseter Clare 1 , P. Andrew Lins 1 Show Abstract
1 Conservation, Philadelphia Museum of Art, Philadelphia, Pennsylvania, United States
This research project focuses on developing and optimizing low-cost, easily applied protective coatings for the conservation of architectural and sculptural metalwork. Fluorinated protective coatings typically possess greater hydrophobicity and resistance to degradation by UV light than organic coatings. In addition to aiming to improve upon the performance of protective coatings, these new coatings systems should have reduced volatile organic components to meet governmental regulations. Using standard spray application methods, polyvinylidine fluoride (PVDF)/acrylic latex topcoats were applied over traditional solvent-borne acrylic basecoats. The resulting films were tested and characterized for their efficacy and weatherability on bronze substrates. Characterization methods included electrochemical impedance spectroscopy, scanning electron microscopy, and micro-fourier transform infrared spectroscopy. The total impedance of the PVDF/acrylic latex films was greater than that of the control acrylic films after 2500 hours of QUV-A exposure, partially due the greater resistance of the fluorinated latex to UV light. Additional characterization of these two coat systems included investigating and understanding the factors that affect their susceptibility to water-whiten. PVDF/acrylic coatings promise improvements upon the materials used by the international conservation community for the protection of such metals as bronze and iron due to increased hydrophobicity and resistance to degradation by UV light, leading to a longer working lifetime.
4:15 PM - Y5.3
Damage Mechanism in Clay-Bearing Stone.
Philippa Duffus 2 , Timothy Wangler 1 , George Scherer 1 Show Abstract
2 Department of Materials, University of Oxford, Oxford United Kingdom, 1 Civil & Env Eng, Princeton University, Princeton, New Jersey, United States
Many sedimentary stones contain clays in the cement between grains, so that the stone expands and softens upon wetting. This can lead to large and destructive differential strains within building stones. Although the stresses are compressive, damage can result from buckling of the surface layer . The nature of the damage depends on the location and size of flaws parallel to the surface. As water invades the surface, bending stresses develop that tend to extend pre-existing flaws (such as local damage from salt crystallization, or weak bedding planes). If the lateral extent of the flaw is large compared to its depth below the surface, the layer of stone above the flaw may buckle .This is apparently the mechanism responsible for damage to many monuments. We report a study of the bending and buckling behavior of an expansive stone that confirms the existence of a buckling threshold. Long plates of stone with various thicknesses were clamped to a table and wetted from one side, leading to expansive strains. For plates with a length/thickness ratio exceeding the predicted threshold of ~65, buckling was observed with deflections of several millimeters. This is consistent with the large displacements seen on some buildings, but such large flaws would not be expected to be present initially. That is, there must be a mechanism for growing small flaws until they reach the critical size needed to permit buckling. In our experiments, we did see small deflections in plates whose dimensions fell below the critical ratio. When the plate is not uniformly wetted, local swelling causes bending moments ; similarly, if a raindrop falls on a stone with a small flaw below the surface, the resulting expansion can put stress on the edges of the flaw causing it to grow. Repeated wetting by rain events could promote growth of flaws until they are large enough to permit buckling, resulting in large displacements of the surface. Whether this will happen depends on the properties of the stone (modulus, strength, swelling strain) and the initial location and size of the flaw. A model of the fracture mechanics for this problem will be presented.Extending the work of Wendler et al. , we show that treatment with a mixture of surfactants is effective at reducing the expansion and preventing damage from this mechanism.1. G.W. Scherer, pp. 633-641 in Measuring, Monitoring and Modeling Concrete Properties, ed. M.S. Konsta-Gdoutos (Springer, Dordrecht, The Netherlands, 2006)2. J.W. Hutchinson, M.D. Thouless, and E.G. Liniger, Acta Metall. Mater. 40  (1992) 295-3083. F. Bloom and D. Coffin, "Handbook of Thin Plate Buckling and Postbuckling", (Chapman & Hall/CRC, Boca Raton, FL, 2001) pp. 7864. E. Wendler, D.D. Klemm, and R. Snethlage, pp. 203-212 in Proc. 5th Int. Conf. on Durability of Building Materials and Components, eds. J.M. Baker et al. (Chapman & Hall, London, 1991)
Pamela Vandiver University of Arizona
Francesca Casadio The Art Institute of Chicago
Blythe McCarthy Smithsonian Institution
Robert H. Tykot University of South Florida
Jose Luis Ruvalcaba Sil Universidad Nacional Autonoma de Mexico
Y6: Technical Art History I
Wednesday AM, November 28, 2007
10:15 AM - Y6.2
The Technology of Frederick Carder's Art Glass.
Israel Favela 1 , Pamela Vandiver 1 Show Abstract
1 Department of Materials Science & Engineering, University of Arizona, Tucson, Arizona, United States
Frederick Carder popularized art glass in America and is remembered as the founder of Steuben Glass in Corning, New York. He was a designer and glass technologist whose factory produced colored and highly decorated vessels that competed with but were less expensive that those of Tiffany Studios. To understand the differences in technology between the competing products of Carder and Tiffany, opalescent white glass formulations, fumed gold lusters and silver-containing glasses used in trailed decoration were analyzed and compared by electron beam microprobe analysis and scanning electron microscopy with simultaneous energy dispersive x-ray analysis and Raman spectroscopy. The cross-sections of opalescent Tiffany glasses have multiple layers rich in the oxides of boron, potassium, phosphorous and lead as has been reported elsewhere, whereas in the case of Carder potassia-calcia-silicate and potassium-lead-silicate compositions were found. Both studios employed metallic salts, iron and tin chlorides, to iridize surfaces with the layer thicknesses between 300 and 800 nm. Silver was also incorporated into trails and other decorative treatments to enhance and deepen the iridized surface. The surfaces are buckled, indicating multiple, post-fuming heat treatments were a standard practice. The compositional data suggests that special bulk glass compositions developed by Carder and probably adapted from those he used during his apprenticeship in England, allowed more efficient and less costly production of Art Nouveau glass that is comparable in quality, but much more symmetrical than that produced at Tiffany Studios in Corona, Long Island.
11:15 AM - **Y6.4
Materials and Techniques of Thai Painting.
Katherine Eremin 1 , Jens Stenger 1 , Narayan Khandekar 1 , Alan Aspuru-Guzik 2 , Leslie Vogt 2 , Ivan Kassal 2 , Theodore Betley 2 , Jo-Fan Huang 3 Show Abstract
1 Straus Center for Conservation, Harvard University Art Museums, Cambridge, Massachusetts, United States, 2 Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, United States, 3 , Philadelphia Museum of Art, Philadelphia, Pennsylvania, United States
The materials and techniques employed in 18th to 20th century art works from Thailand have received little attention compared to those of other Asian countries, most notably China and Japan. A multi-disciplinary study of Thai manuscripts and related art works aims to characterize the materials used, specifically the inorganic and organic pigments and binders, and the painting techniques employed. Samples from these works have been analyzed by a range of techniques, including Raman spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive microanalysis (SEM-EDS). The results suggest a change in palette from the 18th to 20th century due to the introduction of imported pigments, most notably emerald green, Prussian blue and chrome yellow, during the 19th and early 20th century. The analyses show that the green pigment used on the 18th century manuscripts is an organic copper salt, a hydrated copper citrate, which has not previously been identified on art works. The occurrence of this on several art works suggests deliberate manufacture of this unusual pigment. A number of copper citrates differing in their degree of hydration and with slight differences in color have been published, and other variants are possible. These copper citrates have been described as having ‘dubious stability’ and are easily dehydrated and re-hydrated. This suggests some alteration of the original manuscript pigments might be expected, raising questions as to the original color of the pigment and whether the visual appearance has changed over time. In order to assess this, the pigments found on the art works will be fully characterized and any variations identified. The vibrational spectra for different forms of copper citrate will be calculated and compared with those obtained from the pigment samples and from synthesized copper citrate. This will include laboratory based synthesis with pure reagents and synthesis following a 17th century Venetian recipe for refinement of verdigris found by Scott (2002) to result in copper citrate pentahydrate. The stability of the copper citrates and the effects of binders will be investigated in parallel. This will increase understanding of the original appearance of the Thai work of art and of the materials and techniques used by the artisans who created these. David A Scott, 2002, Copper and Bronze in Art: Corrosion, Colorants, Conservation, Getty Publications, pp 287-290.
11:45 AM - Y6.5
Pigment Analysis of Two Thai Banner Paintings.
Jennifer Giaccai 1 Show Abstract
1 Conservation Division, Walters Art Museum, Baltimore, Maryland, United States
The pigments used in two Thai banner paintings (phra bot) were examined using X-ray fluorescence, Fourier transform infrared microscopy and polarized light microscopy. The two paintings dated from the late 18th and the late 19th century, straddling a potential period of change in Thai pigment use. Pigments identified on the paintings follow the trends observed on Thai wall paintings and manuscripts from the same time periods. Pigments used in the banner paintings include vermilion, iron oxide earths, red lead, lead white (hydrocerrusite), calcium carbonate, kaolin, Prussian blue, gamboge, artificial ultramarine, an organic copper salt and a copper-arsenic green.
12:00 PM - **Y6.6
Three-Dimensional Optical Coherence Tomography and High Resolution Photography for Studies in Art Conservation Science.
Jens Stenger 1 , Desmond Adler 2 , Iwona Gorczynska 2 , Henry Lie 1 , Teri Hensick 1 , Ron Spronk 1 , Stephan Wolohojian 1 , Narayan Khandekar 1 , Robert Huber 3 , James Fujimoto 2 Show Abstract
1 Straus Center for Conservation, Harvard University Art Museums, Cambridge, Massachusetts, United States, 2 Department of Electrical Engineering and Computer Science, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States, 3 Lehrstuhl für BioMolekulare Optik, Fakultät für Physik, Ludwig-Maximilians-Universität München, München Germany
Gold punchwork and underdrawing in Renaissance panel paintings are analyzed using both three-dimensional swept source / Fourier domain optical coherence tomography (3D-OCT) and high resolution photography. 3D-OCT can generate en face images with micrometer-scale resolutions at arbitrary sectioning depths, and rejects out-of-plane light by coherence gating. Therefore 3D-OCT is well suited for analyzing pieces where a surface layer obscures details of interest. 3D-OCT also enables 2D cross-sectional imaging and quantitative measurement of 3D features on or near a surface, which is beneficial for analyzing the tools and techniques used to create works of art. One potential application of 3D-OCT is the analysis of gilded surfaces on panel paintings of the early Italian Renaissance, which were frequently adorned with impressions of punches in various shapes. These decorations are important art historical evidence for the relationships between the pictures and their possible creators, since the motif punches are characteristic for specific workshops. Our study demonstrates that 3D-OCT is capable of quantitative measurements of punch depth, and can also identify unique features of the three dimensional punch profiles not visible with high resolution photography. On a painting by the Master of the Orcagnesque Misericordia (active between 1375–1400) a simple circular punch can be recognized at different locations by its microscopic defects. The obscuring effects of the superficial varnish layer can be removed, allowing 3D visualization of the punch impression itself. The OCT images show that the orientation of the punch, in this case, does not change over different passages of the painting. This suggests that the maker did not pause and put the tool down during the application of the punch decorations. Additionally, punches used by the early twentieth-century restorer and forger Frederico Ioni were recorded and compared on a painting from his workshop. Thus, our study provides new opportunities to trace punch tools of particular artists, workshops or forgers. A second focus of the present contribution is the study of underdrawing in an early Netherlandish painting, a key aspect in its technical and art historical understanding. The preparatory drawing and inscription can be revealed by infrared photography, which exploits the fact that paint becomes more transparent in the infrared spectral range. When comparing the visualization of underdrawing using 3D-OCT and high resolution IR photography, similar lateral resolution could be obtained with both techniques. The IR photography images provide slightly better contrast than the 3D-OCT images. However, 3D-OCT provides additional cross sectional information such as the location of the underdrawing within the layered structure of the painting. On the other hand, high resolution IR photography may be more suitable in many instances due to its comparable performance, large field of view, and lower complexity.
12:30 PM - Y6.7
The Grolier Codex: A Non Destructive Study of a Possible Maya Document using PIXE and RBS.
Jose Luis Ruvalcaba 1 , Helena Calvo del Castillo 2 , Sandra Zetina 3 , Elsa Arroyo Lemus 3 , Marie Van der Meeren 4 , Laura Sotelo Santos 5 , Eumelia Hernandez Vazquez 3 Show Abstract
1 , Instituto de Física, Universidad Nacional Autónoma de México, Mexico, DF, Mexico, 2 Dpto. Geología y Geoquímica, Universidad Autónoma de Madrid, Madrid Spain, 3 , Instituto de Investigaciones Estéticas, Universidad Nacional Autónoma de México, Mexico, DF, Mexico, 4 , Coordinación Nacional de Conservación del Patrimonio Nacional, INAH, Mexico, DF, Mexico, 5 , Centro de Estudios Mayas, Instituto de Investigaciones Filológicas, Universidad Nacional Autónoma de México, Mexico, DF, Mexico
Y7: Technical Art History II
Wednesday PM, November 28, 2007
2:30 PM - **Y7.1
Collaboration or Appropriation? Examining a 17th c. Panel by David Teniers the Younger and Jan Brueghel the Younger Using Confocal X-Ray Fluorescence Microscopy.
Jennifer Mass 1 2 , Arthur Woll 3 , Noelle Ocon 4 , Christina Bisulca 5 , Tomasz Wazny 7 , Carol Griggs 6 , Matt Cushman 2 Show Abstract
1 Conservation, Winterthur Museum, Winterthur, Pennsylvania, United States, 2 Art Conservation Department , University of Delaware, Newark, Delaware, United States, 3 Cornell High Energy Synchrotron Source , Cornell University, Ithaca, New York, United States, 4 Conservation , North Carolina Museum of Art, Raleigh, North Carolina, United States, 5 Conservation and Scientific Research, Freer and Sackler Gallery, Smithsonian Institution, Washington, District of Columbia, United States, 7 Institute for the Study, Restoration and Conservation of Cultural Heritage, Nicolaus Copernicus University, Torun Poland, 6 Dendrochronology Laboratory, Cornell University, Ithaca, New York, United States
The 17th c. Flemish painting on panel, The Armorer’s Shop, has long been attributed to David Teniers the Younger (1610-1690). The painting depicts an opulent pile of parade armor at the bottom left foreground, a seated armorer at the bottom right foreground, and a forge surrounded by workers in the middle ground. The Teniers attribution is derived from his signature at the bottom right as well as figural groups and other visual elements that are commonly associated with him and executed in his style. During dendrochronological examination of the painting, a portion of the oak plank comprising the overall structure was found to have been carved out so that a smaller plank (containing the parade armor) could be inserted into the resulting depression. This unusual construction, combined with the identification of several paintings by Jan Brueghel the Younger (1601-1678) depicting the same parade armor, raised questions about the attribution and chronology of construction of the painting. Art historical research suggests that the smaller plank with the armor was painted by Brueghel and that the remainder of the panel with the workers and forge was painted by his brother-in-law Teniers. While Brueghel writes of collaborating with Teniers in his journal, this appears to be the only identified collaboration of the two artists. Conventional microanalysis methods did not resolve the painting’s construction chronology. However, confocal x-ray fluorescence microscopy (CXRF) revealed the composition and location of buried paint layers at the panel interfaces by combining depth scans at a number of adjacent lateral positions to produce virtual cross-sections over 20 mm in length. The relationship of the paint layers at the panel interfaces provided evidence for the armor panel having been painted separately and prior to the rest of the composition. This data, along with dendrochronological and IRR data, provided a chronology of construction for the painting that provided additional evidence for a Brueghel attribution. An overview of the CXRF technique will be provided along with a discussion of how CXRF data relates to data collected using SEM-EDS, FTIR, Raman, conventional XRF, x-radiography, IRR, and dendrochronology.
3:00 PM - Y7.2
Copper Alloys Used in Barye's Surtout de Table of the Duc d'Orleans.
Jennifer Giaccai 1 , Julie Lauffenburger 1 , Ann Boulton 2 Show Abstract
1 Conservation Division, Walters Art Museum, Baltimore, Maryland, United States, 2 Conservation Department, Baltimore Museum of Art, Baltimore, Maryland, United States
The copper alloys of the statues by Antoine-Louis Barye were examined with energy-dispersive X-ray fluorescence. Barye experimented with casting techniques in his own workshop and re-introduced lost-wax casting to the foundries of late 19th century Paris, including the foundry of Gonon and Sons. Some technically complex Barye sculptures were difficult to cast using the more common sand-cast method, and problems resulted at some foundries. Gonon and Sons completed the casting for problematic statues in the surtout de table of the Duc d’Orleans. Examination of the copper alloy compositions differentiates the casts from the various foundries and determines which parts of the surtout were ultimately cast by Gonon and Sons.
3:15 PM - Y7.3
Replication of Glazed Quartzite from Kerma, Capital of Ancient Kush (Sudan).
Lisa Ellis 1 , Richard Newman 2 , Michael Barsanti 3 Show Abstract
1 , Art Gallery of Ontario, Toronto, Ontario, Canada, 2 , Museum of Fine Arts, Boston, Massachusetts, United States, 3 , School of the Museum of Fine Arts, Boston, Massachusetts, United States