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Decorative features on a Greek red-figure stamnos in the collection of the Worcester Art Museum were examined using Reflectance Transformation Imaging (RTI) and scanning laser confocal microscopy. These two surface examination tools helped to answer questions relating to the decorative process, particularly the tools and techniques that Attic painters used to create the so-called glossy black “relief lines” and “relief dots.” This research also incorporated fabricated mock-ups to help understand the ancient technology. It was determined that the relief line was not produced by an extruded method, but with a brush made of one or very few hairs, an idea first proposed by Gérard Seiterle in 1976 and termed Linierhaar. It was observed that not one but two distinct types of relief lines exist: the “laid” line (proposed by Seiterle) characterized by a ridge running through the middle of the line and the “pulled” line (proposed in this paper) which has a furrowed profile. Both line types were reproduced with a Linierhaar. Additionally, relief dots were replicated using a conventional brush. Surface examinations of other red-figure vessels using RTI and the confocal microscope suggest these conclusions apply to vessels of this genre as a whole.
The heat shield is part of a thermal protective system (TPS) essential in shielding the cargo of a spacecraft during reentry to the earth’s atmosphere. The ablated surface of the heat shield is a testimony to the harsh reentry environment, evidenced in melting and charring among other phenomena that occur during reentry at velocity of 9-11 km/sec. The aim of this study was to extrapolate information about atmospheric reentry from the surface of the ablated material. A sample of the heat shield from the test vehicle of the Apollo Program, AS-202, was the subject of the analysis.
For the preliminary studies, selected investigation modes from the Global Optimal Strategy model, developed to identify wear of engineering surfaces, were applied: examination of structure, optical observation, physico-chemical characterization and surface morphology. Instrumentation used included: microscopic surface analysis with Extended Depth of Field composite images (EDF), Fourier transform infrared spectroscopy (FTIR), attenuated total reflectance (ATR), confocal scanning laser microscopy and laser scanning microscopy. The Apollo Program testing vehicle AS-202 (1966) ablated specimen sample was obtained from the collection of the National Air and Space Museum (NASM), Smithsonian Institution, Washington DC. The authors combine their diverse experiences in tribology and in artifacts’ museum conservation so as to contribute to the space heritage material science. This study represents one of the building blocks of a larger project, the Fundamental Model of public outreach and perception (FAM-pop) of complex aerospace technologies.
This paper is focused on results of a survey and study in Northern Nigeria of the inks used in Islamic manuscripts and on related information on the extant traditional technologies of ink production. Knowledge of the specific inks used in the surviving, largely undated Northern Nigerian manuscripts written in Arabic script, often referred to as Islamic manuscripts, informs us about the society that created them and embeds their production within a specific cultural context. In a place such as Africa, where the historical record and archaeological heritage are so vulnerable, we look to all vestiges of material culture in order to expand out understanding of its people, its history and their culture. These manuscripts belong to the West African tradition of Islamic culture and scholarship, of which Timbuktu was a key center. Whilst another goal of the study was to establish a watermark chronology to provide information as to the papers‘ source, when particular papers were made, when manuscripts might have been copied, and their creators‘ paper preferences, the focus of this paper is on identifying and field-testing the inks used in these manuscripts. This study of over twelve thousand folios at fourteen manuscript Northern Nigerian repositories involved 4500 km of road travel and suggested a local, interrelated tradition of dye, ink and pigment fabrication. Preliminary data led to the hypothesis that the local technology provided the basis of the indigenous manuscript production, rather than one derived from the Mediterranean and the Islamic heartlands. Finally, the diversity of these manuscripts in Arabic script reflects a culture in which not everyone was Muslim but in which Islam played a dominant role.
Detection of structural changes has a great importance in conservation and treatment of wooden artifacts found in burial environments. In this study, two wooden samples excavated in Shahr-i Sukhta, an important prehistoric site in eastern Persia, were tested by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). FTIR results showed that decay of lignin occurred. This was accompanied by cellulose degradation. SEM images showed detachment of wood fibers in cross sections and cell wall breakage in tangential sections of the wood samples. These results indicated that the structural change in cellulose and lignin has caused detachment of wood fibers and cell wall breaking. This is the sign of low physical characteristics of wood which has direct relevance to cellulose decay and lignin degradation in middle lamella of wood cells. Cellulose chain breaking over time, has produced stresses in the compound middle lamella layer of the cell wall, that became accelerated in the middle of the lamella layer. Consequently, wood fibers were detached, and disintegration and powdering of wood surfaces occurred.
The effectiveness of using hydroxyapatite (HAP) as a consolidant for carbonate stones was evaluated. HAP was chosen as a consolidating agent since it is notably less soluble than calcite and has a similar crystal structure and a close lattice match to it. Among possible methods for forming HAP, the reaction between the calcite of the stone and a solution of diammonium hydrogen phosphate (DAP) in mild conditions was chosen. Indiana Limestone samples, artificially damaged by heating to 300°C for 1 hour, were treated with a 1 molar DAP solution by partial immersion and capillary absorption for 48 hours or by brushing until apparent refusal and wrapping with a plastic film for 48 hours. After washing in deionized water for 3 days and drying under a fan at room temperature until constant weight, the improvements in dynamic elastic modulus and tensile strength were evaluated. The formation of calcium phosphate phases was observed by scanning electron microscopy (SEM) and the phase characterization performed by energy dispersive X-ray spectroscopy (EDS) and electron back-scattered diffraction (EBSD). The water absorption modification after the consolidating treatment was then assessed. Results show that treated samples experienced significant increases in dynamic elastic modulus and tensile strength, as a consequence of crack reduction and pore filling consequent to HAP deposition at grain boundaries. The sorptivity of the treated samples is reduced by 26-44% (based on treatment technique), so that water and water vapor exchanges with the environment are not blocked.
The Neolithic period Chassey culture in southern France from 4200 to 3500 Cal. BC developed a specialized lithic technology for flint bladelets that used a heating process as an essential part of the production. Experimental archaeology demonstrated that the heating should take place at low temperature somewhere around 250°C. To identify and quantify the physical transformations of flint at low temperature, laboratory and synchrotron experiences have been carried out on a set of heated Barremo-Bedoulian flint samples. According to our measurements, this flint consists of a nanocrystalline matrix of quartz and moganite. Evolution of mesoporous structure was observed during heat treatment. The flint transformed between 200-300°C, resulting in a reduction in the size and volume of porosity. The densification of flint is linked to changes on the nanocrystalline grain boundaries, and it is thought to have a direct impact on the improved mechanical properties from the Chassey culture lithic productions.
Analysis of the composition and microstructure of a Paleo-Indian micro-bead fragment from the Jones-Miller bison-kill site in Wray, Colorado, USE, and dated by radiocarbon testing to 10,200 years ago, showed that fine-motor movements were used to execute a sequence of manufacture on a singular bead. The process involved cleaving a soft, bedded oil shale, diagonally scraping a tubular surface and double-drilling a hole. The last operation caused the bead to fracture, after which it was deposited in a hearth. The raw material consists of bedded clay, silt, opal and quartz particles cemented with carbonaceous material. The presence of similar locally available oil shale with opal inclusions indicates that the raw material was acquired near the Jones-Miller site. Because of high cultural value and small size, only non-destructive analytical techniques were used to characterize the bead, including optical microscopy, UV-VIS, PIXE and XRD. Some 50-micron, previously detached particles were tested by SEM-EDS and compared to local clayey materials, both heat-treated and non-heat-treated, to show that no heat treatment sufficient to cause sintering had occurred. A resource survey in the area around the site and 50 miles to the south produced several comparative materials that were tested by the same methods given above as well as the added methods of DTA and refiring tests.
Developments in non-invasive analytical techniques advance the preservation of cultural heritage materials by identifying and analyzing substrates and media. Spectral imaging systems have been used as a tool for non-invasive characterization of cultural heritage, allowing the collection of chemical identification information about materials without sampling. The Library of Congress has been developing the application of hyperspectral imaging to the preservation and analysis of cultural heritage materials as a powerful, non-contact technique to allow non-invasive characterization of materials, by identifying and characterizing colorants, inks and substrates through their unique spectral response, monitoring deterioration or changes due to exhibit and other environmental conditions, and capturing lost and deteriorated information. The resulting image cube creates a new “digital cultural object” that is related to, but recognized as a distinct entity from the original. The range of data this object contains encourages multidisciplinary collaboration for the integration of preservation, societal and cultural information.
The industrial dyeing apparatus excavated in Pompeii have been preserved and remain in situ. To understand Pompeii’s economy, and its place in the Roman world, it is necessary to first understand the capabilities of a single industry. Before this study, the size of the dyeing industry was calculated by applying theory to a superficial measurement of the remains. This study was the first to realise that to understand an industry it was necessary to reconstruct and use the relevant parts.
The most comprehensive survey of the apparatus was undertaken. A full-scale physical replica was constructed from materials that physically and thermally matched the originals. This study was the first to define the dyeing cycle time, temperatures reached and fuel type and quantity required. Finite Element Analysis (FEA) was used to model a virtual replica to show the effect of external influences on the materials during use. The lead metal data did not exist before this study. This was the first use of FEA to model an archaeological apparatus or artefact of more than one material. The dyeing industry had been far smaller than originally thought.
Archaeological virtual replications tend to be aesthetic. This study produced a rare physical replication. When this is combined with data from the original survey and physical replicas each apparatus is now ‘preserved by record’ and may be recreated. Some of the apparatus in Pompeii have been amended in an attempt to reconstruct and preserve them. This study has shown that the amendments are incorrect and potentially misleading.
Prior to this study the size of the industry was a controversial ‘unanswerable’ question. This study provided a solid foundation that answered the question and illustrated a new approach, through a method that provided a means of preserving the apparatus for the future.
An ultrafast laser irradiation method for the removal of corrosion from Daguerreotypes without detrimentally affecting image quality has been developed. Corrosion products such as silver oxide and silver sulfide may be removed by chemical cleaning but these reactions are hard to control and are often damaging to the underlying silver, ruining the image. The Ti:Sapphire 150 fs laser pulses used in this study are focused to a beam diameter of 60 μm and are normally incident to the Daguerreotype. It was found that the corrosion layer has a lower material removal threshold than silver allowing for removal of corrosion with minimal removal of vital information contained in the silver substrate.
Vast numbers of bronze coins have been, and continue to be, excavated from archaeological sites around the Greco-Roman world. While often of little value from a strictly numismatic point of view, these coins provide invaluable data within their respective stratigraphic contexts and are used to date occupational and architectural phases more precisely than by ceramics alone. Unfortunately, the build-up of corrosion and mineralization on these coins during their centuries of burial often obscures their legends. Rather than employing potentially destructive and time-consuming chemical or mechanical cleaning techniques to reveal these features, commercially available Micro-focus X-Ray CT systems are now sufficiently well developed to reveal original surface features and to permit identification by a trained numismatist without any cleaning at all.
Gongyi is the birthplace and one of the most famous production areas of white porcelain in China. In this study, white porcelain samples from the Northern Wei to Tang Dynasties excavated from Baihe and Huangye kiln sites were analyzed to investigate microstructure and its physicochemical basis. The result demonstrates that the formation of an interaction layer of Anorthite crystals and the accompanied phase-separation structure at glaze-body boundary is a common character of microstructure. And there is little probability for crystal precipitation within the glaze layer.
In 2010, Mexico celebrates 200 years since the beginning of the Independence war that gave rise to the independent Mexican Empire in 1821, and afterwards to the Mexican Republic. This document had two original copies; one of them was lost in a fire at the beginning of twentieth century, while the second was stolen and finally returned to Mexico in 1960, after a long history of events. This document is kept in the General Archives of Nation (AGN), Mexico.
The “Independence Act of the Mexican Empire of 1821” was written on paper using iron-gall inks. The document has two parts: a declaration and a set of 36 signatures of Iturbide and other people involved in establishing the Independence of Mexico.
The non-destructive study of this document was carried out in order to answer several questions: legitimacy, composition of the materials (paper and inks), deterioration conditions and a possible sequence of writing and the signatures. For these purposes several in situ techniques were used: optical microscopy, ultraviolet and infrared light imaging, portable X-ray Fluorescence and Raman Spectroscopy. This work presents the main results of this analytical methodology applied to the Mexican Independence Act. The results indicate that several inks were used in the manuscript and that the paper has an aging consistent with a nineteenth century document. From these results, we consider that the document examined is genuine and not a copy or facsimile of the original act.
Two separate pottery types, Kura-Araxes and Velikent Fine Wares can be found together at a number of Early Bronze Age sites in the Northeastern Caucasus. These ceramics are strikingly different in their appearance. Velikent Fine Ware bears indications that it may have been fired at a much higher temperature than Kura-Araxes wares. The obvious contrasts in their production raised suspicions that Velikent Fine Wares represented either an import or an intrusive production regime perhaps linked to the advent of Bronze metallurgy in this region or at least relying on a shared pyrotechnology. Prior results of Xeroradiographic analysis and INAA are merged with recent re-firing analysis to examine these hypotheses. The findings suggest that while a specific link between metal and pottery production cannot be confirmed, the emergence of divergent firing practices within an otherwise unified production tradition speaks to complex relationships between craftspeople within Early Bronze Age communities in the Caucasus.
The decorative polychrome history of a remarkable depiction of the “Guanyin of the Southern Sea” dating to the 11th-12th centuries C.E. (Nelson-Atkins Museum of Art, Kansas City, #34-10) has been studied by integrating the results of Scanning Electron Microscopy with Elemental Analysis by X-ray Spectrometry, Raman Spectroscopy, Fourier Transform Infrared Spectroscopy and Polarized Light Microscopy. This 2.4m by 1.65m sculpture, carved almost entirely from a single Populus tree, has been attributed to Northern China and offers important points of comparison to previously studied works in the Victoria and Albert Museum and Rijksmuseum, with which it differs in certain important respects. Evidence for the original polychrome color scheme and those of at least three successive historical redecorations (two of which have been assigned ages by radiocarbon dating of paper interlayers) was found throughout the figure. By integrating the different forms of information obtainable from the methods cited above, it was possible to more fully describe complex pigment mixtures used to render different parts of the draperies. Both fracture sections and prepared cross sections serve different functions in revealing aspects of the paint preparation and its subsequent alteration. The differentiation of polymorphs of copper trihydroxychloride, made possible by Raman spectroscopy, allowed us to identify manmade botallackite with distinctive particle morphology as an important pigment of the intermediate period decorations, while elemental analysis of tin oxide traces showed that manmade atacamite used in other colors was derived from corroded bronze. Elemental analysis allowed distinctions to be made in the shade of gold leaf applied in different periods from cross sections without divesting the sculpture of later paint applications. The cross sections also provided evidence for the existence of flat gold line-work in areas subsequently redecorated with raised gilt brocades. Several combinations of the organic pigment indigo and inorganic paint constituents such as lead white, azurite, malachite and quartz reveal the means of adjusting shade and optical effects in closely-related paint applications. The results obtained by employing complementary techniques of analysis have served to greatly expand our understanding of the original use of polychrome decoration in the late Liao or Jin periods and its subsequent evolution, while alerting us to important Chinese innovations in the manufacure of pigments.
The search for durable dyes led several past civilizations to develop artificial pigments. Maya Blue (MB), manufactured in pre-Columbian Mesoamerica, is one of the best known examples of an organic-inorganic hybrid material. Its durability is due to the unique association of indigo molecule and palygorskite, a particular fibrous clay occurring in Yucatan. Despite 50 years of sustained interest, the microscopic structure of MB and its relation to the durability remain open questions. Combining new thermogravimetric and synchrotron X-ray diffraction analyses, we show that indigo molecules can diffuse into the channel of the palygorskite during the heating process, replacing zeolitic water and stabilizing the room temperature phases of the clay.
Non-destructive Raman spectroscopy was applied to three kinds of porcelain glaze samples: (i) Guan wares of Song Dynasty; (ii) Imitated Guan wares; (Both (i) and (ii) are from the Palace Museum (Beijing, China) collections); (iii) Porcelain shards are collected from the Xiuneisi kiln site which is one of two excavated Guan ware imperial kilns in Hangzhou, the capital of the Southern Song Dynasty. Raman spectra of the glassy phase network were used to discuss the composition and firing temperature of the glaze. The index of polymerization (Ip) is strongly correlated with the firing temperature and the composition of the glaze. According to the Ip values of the glaze, those Guan wares (i) can be classified into three groups. The provenance of Guan wares (i) was discussed by comparing the Ip values to imitations (ii) and shards(iii). The study of classification and provenance are also supported by the X-ray fluorescence data. The Ip values of several recently prepared glazed samples of known firing temperature were measured to build empirical relationship between the Ip value and the firing temperature. Based on the relationship, the firing temperature of the Guan ware glazes was at 1170-1300°C.
The Athlit ram, a bronze warship ram from a 2nd Century BCE Roman-era galley, was found in 1980 off the coast of Israel at Athlit, and is now displayed at the National Maritime Museum, Haifa, Israel. It meant to fit on the prow of a medium-sized oared warship. This ram is the only known surviving example of this ancient naval weapon. Inside the bronze ram some of the ship’s wood is still preserved. We have recently studied a piece of the ram removed during early conservation. Remnant metal, corrosion products, and mineralized and pseudomorphed wood have all been found and examined by light optical metallography, x-ray diffraction, scanning electron microscopy, and microanalysis using energy dispersive x-ray mapping. The main corrosion product on the Athlit Ram is identified as covellite (CuS), and the entrained material is pseudomorphed cedar wood. Analysis indicates the lumen to be replaced by calcium carbonate and the cell walls to be replaced by covellite, consistent with the matrix.
Faience production methods include efflorescence, direct glaze application, and cementation glazing. However, similar processing has been used with a variety of other materials, such as glazed monolithic quartz, ground and re-fired faience, and steatite bodies. Furthermore, faience technology has been linked by similar processing to glass, synthetic pigment and glazing technologies. Here we reinforce these cross-craft relationships by comparing the range of similar functioning chemical elements in faience and glazed artifacts from a variety of archaeological sites that range from the Indus Valley to the Mediterranean. This broad comparative method based primarily on x-ray fluorescence analysis reveals trends in faience production, relationships with metallurgical technologies, and aspects of processing that provide areas of study that may be considered more closely in the future.