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In a set of composite samples of oil or alkyd paints, over acrylic grounds, naturally aged for eight years, some of the samples delaminated. Samples were analyzed with X-ray fluorescence (XRF), inductively coupled plasma (ICP), Fourier transform infrared - attenuated total reflectance (FTIR-ATR) and atomic force microscopy (AFM) as well as other techniques not detailed in this paper. Results indicate the main cause of delamination is metal soaps in the oil paint and particularly zinc soaps. The ground is a minor consideration as well, rougher grounds providing better adhesion than smooth ones.
Aegae, 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
Crystallization of salts is a common cause of damage in porous building materials. Understanding of the crystallization mechanism of salts is important in order to prevent or avoid the problem. Subflorescence of salts (i.e., crystallization within the pores of the body) can induce scaling and cracking, while efflorescence (i.e., crystallization in a film of solution on the exterior surface of the body) does not generally affect the coherence and endurance of the building materials.
In this paper, we deal with the crystallization behavior of two salts, sodium sulfate and sodium chloride, in two bricks with different capillary porosity. The results reveal quite different crystallization behavior depending on salt and substrate.
The supersaturation of the solution is induced in our experiments by evaporation. Indeed, the main reason for the different behavior of these salts is the different ability for supersaturation. Thus, the sodium sulfate solution is prone to be much more supersaturated than sodium chloride. Furthermore, the solution transport, which depends on salt properties, material porosity, pore-clogging and climatic conditions, affects the position of the drying front and, with it, the crystallization front leading to the formation either of efflorescence or of subflorescence. A simulation of the experiments helps us to understand the effect of the influencing factors on the crystallization pattern. Therefore, considering both factors, supersaturation ratio and solution transport, it is possible to predict the different crystallization behavior observed in the experiments.
A ceramic plaque was studied that depicts the figurative part of the lower half of the Moses Panel from the gilt bronze doors that Lorenzo Ghiberti and his workshop installed on the east side of the San Giovanni Baptistery in Florence, Italy. The doors were completed in 1452, and thermoluminescence dating of two areas of the ceramic relief panel gave a broad, but consistent fifteenth century date. No differences were found in the composition, microstructure or phase assemblage of the two stylistically distinct parts of the ceramic panel. Microscopy and radiography were used to reconstruct the forming methods and sequence of steps in manufacture and restoration.
A pre-Columbian silver ring from Incallajta, Bolivia, recovered from an archaeological excavation is composed of a thin sheet of silver bent to form the ring. Two small wires in the shape of the infinity sign are joined to the surface of the ring. Four green stone beads were laid inside the four cavities formed by the wires. Energy dispersive spectroscopy (EDX) and Particle Induced X-rays Emission (PIXE) analyses of the beads proved that they were turquoise. Examination with a stereoscopic binocular microscope indicated that the two wires could have been soldered to the ring by reduction welding, because copper corrosion products were found in the interface of the welding, similar to those seen on two modern silver objects from Indonesia, decorated with granulation. Since reduction welding is a technique not reported before in pre-Columbian metallurgy, further analyses were carried out to prove that it was used here. Thus, the ring was analyzed with Scanning Electron Microscopy (SEM-EDX) and external beam PIXE, showing with certainty that the copper content in the area of the welding was higher than in any other part of the ring, with increasing copper amounts towards the center of the weld.
Many clay-bearing sedimentary stones such as Portland Brownstone will swell when exposed to water, and this can generate damaging stresses as differential strains evolve during a wetting cycle. Current swelling inhibitors, consisting of α,ω-diaminoalkanes, can reduce swelling in Portland Brownstone up to 50%. In this study, through X-ray diffraction and swelling strain experiments, we demonstrate that the α,ω-diaminoalkanes inhibit swelling by substituting for interlayer cations and partially hydrophobicizing the interlayer, then rehydrating on subsequent wetting cycles. We also introduce the copper (II) ethylenediamine complex as a potential treatment for swelling inhibition.
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. But the act of making an object is, by its very nature, also an intangible part of human heritage. 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 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 intangible data about craft processes 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 here are drawn from fieldwork conducted in 2007 at a Bonpo monastery (Serling) and nearby villages in the Amdo region of the eastern Tibetan culture area (in Sichuan Province, China). Bonpo practices, which pre-date the introduction of Buddhism into Tibet, incorporate a variety of ritual crafts that are strongly rooted in a complex web of intangible relationships, behaviors, meanings, purposes, and beliefs. This paper focuses on votive clay objects (tsha-tshas) and barley-dough offering sculptures (tormas). Processes encompassing intangible aspects that are explored include the decision to make an object, when to make it and in what form, selection of raw materials, methods for processing the raw materials, fabrication procedures, selection of who will be involved in fabrication steps, where to place the finished object, and whether it will be preserved for the long term or considered to be only a temporary object. Results are placed in the context of larger theoretical issues regarding documentation and preservation of intangible elements of cultural heritage as part of a study of materials and technological processes.
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 technology in use across the Iranian Plateau. Materials analyzed from Godin Tepe include crucibles, furnace and tuyere fragments, ore, and metal artifacts dating to the early third through late second millennium B.C.E. The production materials 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 cooling rates and temperatures attained during smelting and casting operations in antiquity. In addition, the analysis of approximately 60 metal artifacts (out of the two-hundred plus that were excavated) have contributed greatly to understanding the variability in manufacture methods present during this time period. The results of this investigation support two significant conclusions. First, the measurement and evaluation of secondary dendrite arm spacing of cast artifacts and crucible prills provides insight to the processes and cooling methods employed by ancient craftsmen. Second, the wide range in manufacturing methods shown by the microstructures of non-utilitarian artifacts, offers strong evidence for the presence of multiple producers who copied styles and typology, but not technological methods from their contemporary craftsmen.
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.
The pigments used in two Thai banner paintings (phra bot) were examined using X-ray fluorescence (XRF), Fourier transform infrared microscopy (FTIR) and polarized light microscopy (PLM). The two paintings examined dated from the late 18th and the late 19th century. The paintings examined follow the trends observed on Thai wall paintings and manuscripts from the same time periods. Pigments identified include vermilion, iron oxide earths, red lead, lead white (hydrocerrusite), calcium carbonate, kaolin, Prussian blue, gamboge, artificial ultramarine, copper citrate and a copper-arsenic green.
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 reference lead-tin bronze alloys.
The technology of artifacts is analyzed and reconstructed by comparison with known craft practices, the physical and chemical constraints imposed by the raw materials, and the sequence and steps for processing those materials to achieve certain optical and mechanical properties. Understanding of craft knowledge is best pursued by practice, coupled with technical analysis. Six case studies of hands-on, undergraduate student laboratory projects are presented. The studies include testing parameters for the making of stenciled hand images similar to those at caves such as Gargas from the Upper Paleolithic period in France, the variation in processing required to produce Egyptian blue pigments and objects, controlling composition to form either green or turquoise-blue colors in Islamic lead-containing glazes, optimizing the ratio of various pigments to gum Arabic medium in tomb paintings to evaluate the application and durability, molding East Asian gokok beads in imitation of jade, and making and radiographing a mock-up of a damaged statue on the facade at the San Xavier Mission as a standard for comparison with the original. In each case, various parameters are varied to model the appearance, structure and composition of an object, and the students benefited from the experience of developing research questions and from their involvement in original research projects.
For nearly four millennia, Afghanistan has been at the crossroads of Eurasian commerce and remains ethnically and linguistically diverse, a mosaic of cultures and languages, especially in the north, where the Turkestan Plain is 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. The research reported herein involves the comparative analysis of archaeological ceramics from a series of archaeological sites excavated in northern Afghanistan in the mid-1960s by the late Louis Dupree and me. I served as the field director (1965-1966) and analyzed the ceramics excavated from all six archaeological sites. These were Aq Kupruk I, II, III, and IV located in Balkh Province (north-central Afghanistan) and Darra-i-Kur and Hazar Gusfand situated on the border between Badakshan and Tarkar Provinces (extreme northeastern Afghanistan). Ten of the 72 ceramic types from the Aq Kupruk area have been published [1, 2, 3] but 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 the pottery dates to the BCE-CE period. The results of ceramic typological, macroscopic, binocular and petrographic microscopy (thin-section analysis and point counting) are reported.
Laser ablation inductively coupled plasma time-of-flight mass spectrometry (LA-ICP-TOFMS) was used to study the trace element chemistry of coral red and black gloss slip decoration on Greek Attic pottery (6th century BC). The distribution of trace elements in the body fabric and glaze slips were found to be correlated suggesting the raw materials came from a single source. Furthermore, the so-called high calcium and magnesium (HCM) coral red was found to be a less refined material than black gloss, with trace element characteristics suggestive of a carbonate phase in the raw material. This carbonate component may have imparted refractory properties to the HCM coral red slip material during the three-stage oxidative-reductive-oxidative firing used to produce Attic pottery, allowing it to remain porous and re-oxidize during the final firing step, thus creating its final red color. The so-called low calcium and magnesium (LCM) coral red, on the other hand, was found to be more refined than the HCM coral red slip which suggests that two separate firings would have been needed to produce the red color of this material.
X-ray fluorescence (XRF) and Accelerator Mass Spectrometry (AMS) techniques were applied to four pieces of ancient Mongolian textiles in order to assist cultural studies of the most significant era of medieval western Asian culture. Radiocarbon dating using Accelerator Mass Spectrometry (AMS) was performed in order to determine the historical age of these pieces. Then, X-ray fluorescence analysis using Synchrotron Radiation (SR-XRF) was carried out in order to obtain elemental maps as well as investigate their constituent elements. Results showed that the textiles were produced between13th and 14th century, and possessed elements such as Au, Cu, Fe and Ti were traced in these pieces whereas Au was used to make gold threads. Cu, Fe and Ti are well known as metallic mordant. In addition, high resolution images were obtained using Scanning Electron Microscope (SEM) to observe the textile structure and their weaving conditions. The whole collected data can assist in bringing into light and facilitate a deeper understanding of the medieval Mongolian cultures, the textile technology, staining techniques, material process technology of the Mongolian Empire and their relations with the neighboring east and central Asian cultures, such as Persia, India and China.
The preparation and performance of a silver nanoparticle-based sensor for use in Oddy tests are reported. A suspension of spherical silver nanoparticles (Ag NPs) (mean diameter of 30 nm, absorption of surface plasmon resonance (SPR) at 428 nm) in methanol was synthesized and the Ag NPs were self-assembled into monolayer films on glass slides, using polyethylenimine as a linking agent. 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, after a brief alteration of the spectrum due to particle dispersal, with no significant decrease in the SPR intensity after 1.5 months at 60°C and 100% RH. The sensitivity of Ag NP films to sulfide gases emitted from a test wool fabric 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. Elemental analysis with energy dispersive x-ray spectroscopy confirmed that sulfur had been incorporated into the Ag NP film. Ag NP assemblies of lower NP density were created that indicated the presence of sulfide gases prior to significant tarnishing of a Ag foil. The results demonstrate that the Ag NP films can be used as sensitive, quantitative optical sensors to replace Ag foils in the Oddy test system.
Glazes found on ancient Nubian quartzite sculpture were characterized in a previous study by scanning electron microscopy/energy-dispersive X-ray spectrometry (SEM/EDS). Now in the collection of the Museum of Fine Arts, Boston, these objects were excavated in the early 20th century by the joint Harvard University-Boston Museum of Fine Arts Expedition, in ancient Kerma, the capital of ancient Kush. The project presented here attempts to recreate the ancient technology used to glaze quartzite with compositions determined in the previous study. Raw and fritted experimental glazes were prepared, as well as an alkali paste mixed with a copper colorant. All of the samples were fired in modern kilns. After firing, samples of the glazes and their quartzite substrates were examined with SEM/EDS.
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 banner paintings aims to characterize the materials used, inorganic and organic pigments and binders, and the painting techniques employed. Samples from these works have been analyzed by a range of techniques, including x-ray flourescence (XRF), 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 most 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 a number of different art works suggests deliberate manufacture of this unusual pigment. The color of the copper citrates differs depending on their hydration state and they 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 altered with time. In order to assess this, the pigments found on the art works must be fully characterized and any variations identified. The study includes laboratory based sythesis with pure reagents and synthesis following a recipe for refinement of verdigris given in a 17th century Venetian manuscript.
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 regularly worked with the foundry of Honoré Gonon, who re-introduced lost wax casting to 19th century Paris. Two of the technically complex Barye sculptures in the surtout de table of the Duc d'Orleans were difficult to cast using the more common sand casting technique. Problems with the sand casts sent to other foundries resulted in Gonon completing the casting for problematic statues in the surtout, after Gonon had completed lost wax casting of the three hunt scenes initially sent to his foundry. 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.
Many ancient Asian and Japanese 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.