Most of what is known about the Iron Age in Southeastern Kazakhstan has been learned from kurgan burials and historical accounts describing the largely nomadic lifestyle of steppe populations from the 8th century B.C.E. to the 5th century C.E. Recent archaeological surveys however, are revealing an unexpectedly large number of settlements at the edges of the steppe, along the northern slopes of the Tien Shan Mountains. One of these sites, Tuzusai, has provided a wealth of ceramic finds that offer insight into local pottery production traditions and their social and material contexts. Our preliminary analysis of both pottery and local clay and temper resources suggests that the community at Tuzusai engaged in feasting activities that incorporated a diverse vocabulary of pot forms. The overwhelming majority of these forms appear to have been locally produced using assembly strategies that responded to shortcomings in available raw materials. Given our current understanding of local production resources and the technical difficulty associated with the production of thin walled forms using these materials, we suggest that these ceramics may be high-status goods valued not solely for their function in feasting activities, but for the labor and skill required to produce them.

Marble, a non-porous stone composed of calcite, is subject to acid rain dissolution due to its relatively high dissolution rate. With the goal of preventing such damage, we have investigated the deposition of films of relatively insoluble hydroxyapatite (HAP) on marble. This paper investigates the factors that affect the nucleation and growth kinetics of HAP on marble. A mild, wet chemical synthesis route, in which diammonium hydrogen phosphate (DAP) salt was reacted with marble, alone and with cationic and anionic precursors under different reaction conditions, was used to produce inorganic HAP films on the mineral surface. Film nucleation, growth and metastable phase evolution were studied, using techniques such as scanning electron microscopy (SEM) and grazing incidence X-ray diffraction (GID). The onset of nucleation, and the growth rate of the film, increased with cationic (calcium) and anionic (carbonate) precursor additions. The calcium and phosphate precursors also influenced metastable phase formation, introducing a new phase.

This paper discusses the effectiveness of hydroxyapatite (HAP) as an inorganic consolidant for physically weathered Indiana Limestone, and as a coupling agent between limestone and a silicate consolidant. A double application is investigated, in which samples are coated with HAP followed by a commercially available silicate-based consolidant (Conservare® OH-100). To artificially weather limestone, a thermal degradation technique was utilized. Diammonium hydrogen phosphate (DAP) salt was reacted with limestone, alone and with cationic precursors, to produce HAP films. The dynamic elastic modulus, water sorptivity and tensile strength of the treated stones were evaluated. HAP was found to be an effective consolidant for weathered Indiana Limestone, and its performance was enhanced by addition of millimolar quantities of calcium chloride. However, HAP was not useful as a coupling agent; a double treatment with DAP is more effective than sequential treatment with DAP and Conservare®.

As one of the most typical ancient cultural relics in southern China's minority regions near Changsha in Hunan province, the magnificent Laosicheng ruins excavated recently have been included in the UNESCO World Cultural Heritage Tentative List. Urgent conservation of excavated Laosicheng ruins brings about the need for a study of the formulation and properties of construction materials used, including earth, stone, mortar, and brick. In the present study, comprehensive analyses were carried out to determine their raw material compositions, mineralogical, and microstructural properties using sheet polarized optical microscopy, scanning electron microscopy with energy dispersive spectrometer, thermogravimetric/differential scanning calorimetry, X-ray powder diffraction, and Fourier transform infrared spectroscopy. Special attention was paid to mortars, which were the most widely used in building the Laosicheng. Results show that mortar used as external render of the city wall is mainly built up from inorganic CaCO3 and MgCO3 based hybrid materials produced by the carbonation of Ca(OH)2 and Mg(OH)2 with a small amount of sticky rice. In contrast, mortar used to bond stones of the city walls is a traditional mortar that does not contain sticky rice. This study is a part of a huge interdisciplinary project aimed to clarify the role of organics in ancient China’s organic-inorganic hybrid mortar, which can be considered as one of the greatest invention in construction material history. The results provide valuable basic data and restoration strategies that can be used in the conservation of the ruins as well.

Calcium hydroxide (Ca(OH)2) is one of the most interesting materials used to consolidate stone sculptures, monuments, mortars or wall paintings. In this study, we reported on the synthesis and characterization of surface modified Ca(OH)2 nanoparticles as a dispersion with enhanced kinetic stability and the applications for the conservation of sandstone monuments. Uniform hexagonal Ca(OH)2 nanoparticles (∼35nm) were obtained by mixing NaOH and NaCl aqueous solutions at 100∼175oC using homogeneous-phase reactions. It was further demonstrated that 3-(Methacryloyloxypropane oxygen) trimethoxysilane surfactant agent can significantly reduce agglomeration and simultaneously improve specific surface area of as-synthesized Ca(OH)2 nanoparticles. Brunauer-Emmett-Teller (BET) measurement showed that specific surface area of modified Ca(OH)2 nanoparticles reaches up to ∼48.78m2/g, about 2.5 and 3.4 times higher than that of unmodified and commercial ones, respectively. The kinetic stability of Ca(OH)2 despersion can be further enhanced and its viscosity can be decreased by optimizing the ratio of ethanol and n-propanol. Especially, a technique, which combined the Ferroni-Dini method and dispersion of Ca(OH)2 nanoparticles with enhanced kinetic stability, was proposed to effectively desalinate and consolidate the decayed stone, as evidenced by significant decreases of the porosity and concentration of detrimental Cl- and SO42- ions in the severely decayed sandstone samples from the Yungang grottoes.

The Gran Pirámide, a Mexican cultural heritage site, is located at the archaeological site of Cholula, Puebla, Mexico. At the base of its platform this pyramid is the largest in the world. It was built in layers from 800 to 1100 AD by the Cholultecan pre-Hispanic culture. The archaeological site is famous by its great mural paintings that have been well-studied. The pyramid was built with earthen construction, a system of multiple bulding episodes with layers of adobe. The building material, adobe, has not been well studied. Due to its fragile condition, a more extensive study was conducted to understand the behavior of the building and the mural paintings substrate, in order to propose conservation strategies.

Geological context of the area was the starting point to propose the relevant materials used in its construction. That was a fundamental key for the interpretation of the experimental techniques used that include X-ray Diffraction (XRD), Particle-Induced X-ray Emission (PIXE), 29Si and 27Al Nuclear-Magnetic Resonance with Magic-Angle Spin (NMR-MAS), Thermal Analysis, Optical and Scanning Electron Microscopy (SEM) and colorimetric measurements.

The results obtained from the original adobes have been compared with fresh soils from horizons related with pre-Hispanic activity. The results indicate presence of amorphous materials and neo-mineral formation besides feldspars and opal. The amorphous phases have been identified by NMR-MAS and SEM.

Differences were found in the composition from the adobe used for the joints, mainly in the clay fraction, that can be distinguished by color and that guided to group the information acquired.

These results provide new information on the composition and microstructure of adobes from the Gran Pirámide of Cholula. Further studies will involve soil physics methods and erosion tests to complete the task of having a comprehensive knowledge of the earth architecture of the pyramid.

Volatile organic compounds (VOCs) can be hazardous to human health and can negatively impact the long-term stability of art objects. This research evaluated the VOC adsorbent properties of three materials commonly used in museums as humidity regulating or air filtering agents. Silica gel, activated charcoal, and zeolite powder, materials often placed in proximity to art objects, were analyzed using Thermal Desorption GC-MS to qualitatively identify adsorbed VOC’s from model environments. This research compared the adsorbing capabilities of these materials with a solid-phase micro-extraction (SPME) carboxen/polydimethyl siloxane fiber to frame their adsorbing powers. It was found that different adsorbents have very different ranges of adsorption for the chemicals tested. Silica gel powder and zeolite powder have the greatest sensitivity for acetic acid over a 24 hour exposure period. Zeolite powder and activated charcoal were more sensitive for identification of naphthalene. Silica gel powder proved to be the most sensitive adsorbent overall. This research discovered that the methods used to condition silica gel pellets for reuse need to be re-examined in light of fact they trap VOC’s, especially as it was observed that VOC’s desorb from the silica gel pellets under ambient conditions.

Colonial mural painting developed in Mexico in XVI century after the conquest of the pre-Hispanic cultures following the evangelization process little information exists about the chronology of the paintings and workshops, the painters, the pictorial techniques or the materiality of this art work.

In this work, we present the non-invasive methodology of study of the pigments and other components of nine mural paintings in three colonial Augustinian ex-convents located in Epazoyucan, Actopan and Ixmiquilpan, in the state of Hidalgo, central Mexico. These places were selected not only because of the inherent value and iconographic characteristics of the paintings, which date to the XVI and XVII century, but also because they are in the same region and are well preserved and in good condition. Then it is possible to compare their materiality and get new information to answer to some of questions related to these paintings.

X-ray Fluorescence (XRF) and Raman spectroscopy were conducted using portable equipment on scaffolds after a global examination under ultraviolet light. We were able to distinguish between different pigments used for different colors such as vermillion, orpiment, and a copper pigment, for the bright red, gold yellow, and green, respectively. These pigments are characteristic of the known Mexican Colonial color palette. Apart from this, we also found the presence of indigo in the blues, minium, and cochineal. A first comparison among the mural paintings of the three sites indicates different palettes and painting periods.

A Moche cast copper alloy object was investigated with focus on three main areas: the alloy composition, the casting technology, and the corrosion process. This complex artifact has thin connective arms between the body and the head, a situation that would be very difficult to cast. The entire artifact was mounted and polished allowing for complete microstructural and microchemical analysis, providing insight into the forming technology. In addition, gigapixel x-ray spectrum imaging was undertaken to explore the alloy composition and the solidification process of the entire sample. This process used four 30 mm2 SDD-EDS detectors to collect the 150 gigabyte file mapping an area of 46 080 × 39 934 pixels. Raman analysis was performed to confirm the corrosion compounds.

Hawaiian barkcloth (‘kapa’) is a traditional fabric made from beaten plant fibers. Because of its function in both utilitarian and chiefly ornaments, kapa is intimately tied to the history and traditions of Hawai’i. In the 19th century kapa was gradually replaced with imported textiles and the practice was lost. The traditional methods used to manufacture kapa are now only known from historic descriptions by early missionaries and explorers. Since the 1970s, cultural practitioners began an effort to revive this artform and are experimenting with materials and techniques to reproduce kapa with the quality of historic artifacts.

Research has been undertaken at the Bishop Museum using a multi-analytical approach to determine the colorants. The Bishop Museum holds the world’s best collection of kapa, including some of the earliest pieces collected from Cook’s voyage in the 18th century. The research has focused on a comprehensive survey of over 150 pieces of kapa with x-ray fluorescence spectroscopy (XRF). In some cases, samples were removed and analyzed with UV-Vis-NIR fiber optics reflectance spectroscopy, Fourier transform infrared spectroscopy (FTIR) and chromatographic techniques, including high performance liquid chromatography (HPLC). Scientific results document the use of traditional pigments and dyes as well as the incorporation of imported materials in the 19th century. Results are interpreted by period, design and use, as well as within the context of historic descriptions. An important aspect of this work is close collaboration with cultural practitioners experienced fabrication methods that have been successful in the recreation of kapa. With continued research, the goal is to ultimately gain a greater knowledge of historic materials and techniques for the continuation of this important tradition.

Our knowledge of glass production in ancient Egypt has been well augmented not only by the publication of recently excavated materials and glass workshops, but also by more recent materials analysis, and experiments of modern glass-makers attempting to reconstruct the production process of thin-walled core-formed glass vessels. The small but well preserved glass collection of the Freer Gallery of Art in Washington, D.C. was used to examine and study the technology and production of ancient Egyptian core-formed glass vessels. Previous study suggests that most of these vessels were produced in the 18th Dynasty in the 15th and 14th centuries BCE, while others date from the Hellenistic period and later. In an ongoing project we conducted computed radiography, x-ray fluorescence analysis and scanning electron microscopy on a selected group of vessels to understand further aspects of the ancient production process. This paper will provide an overview of our recent research.

A combination of FTIR, normal Raman, SERS, Py-GC/MS and XRF was used to analyze commercial bistre samples to determine specific biomarkers that will allow for a rapid identification of the pigment in works of art. The results of the XRF analysis showed that potassium, calcium and iron are the main elements present. Characteristic bands belonging to phenolic components of lignin were observed in the FTIR spectra. The SERS analysis provided a fingerprint that may originate in the polymerization of the phenolic components catalyzed by the presence of the nanostructured silver surface under alkaline conditions. The Py-GC/MS analysis revealed the presence of lignin and cellulose biomarkers and a series of polycyclic aromatic hydrocarbons. The similarities observed between the commercial samples studied suggest that both originate in the same raw material, hardwood. The results demonstrate the potential of the multi-technique approach used for the characterization of this complex black-brown pigment.

Soap formation in traditional oil paintings occurs when heavy-metal-containing pigments, such as lead white, 2Pb(CO3)2·Pb(OH)2, and lead-tin yellow type I, Pb2SnO4, react with fatty acids in the binding medium. These soaps may form aggregates that can be 100-200 μm in diameter, which swell and protrude through the paint surface, resulting in the degradation of the paint film and damage to the integrity of the artwork. In addition, soap formation has been reported to play a role in the increased transparency of paint films that allows the painting support, the preparatory drawing, and the artists’ alterations to become visible to the naked eye. The factors that trigger soap formation and the mechanism(s) of the process are not yet well understood. To elucidate these issues, chemical and structural information is necessary which can be obtained by solid-state 207Pb, 119Sn, and 13C nuclear magnetic resonance (NMR). In the present study, a combination of 207Pb NMR pulse sequences was used to determine accurately the NMR parameters of lead-containing pigments and lead carboxylates known to be involved in soap formation, such as lead palmitate, lead stearate, and lead azelate. These results show that the local coordination environment of lead azelate is different from lead palmitate or lead stearate and therefore it is unlikely that lead azelate would be incorporated into an ordered structure containing lead palmitate and lead stearate. In addition, the chemical shifts of the pigments obtained are different from those of the soaps, demonstrating that 207Pb NMR is useful in characterizing the components when present in a mixture, such as a paint film. The NMR methods discussed can also be applied to other Pb-containing cultural heritage materials, electronic and optoelectronic materials, superconducting materials, and environmentally contaminated materials.

The movement of fluids through a porous medium is a function of the material type and the size and morphology of the voids. In the conservation of painted artworks, the movement of materials (for example, cleaning solutions) is a major factor in how a work reacts to treatments and a large influence on how the work will change with time. Of particular importance in the conservation of painted surfaces is the preparatory layer. This is a highly active transport medium because it is generally highly porous and a comparatively large and uniform component of a painted surface. In this work, a gesso film of calcium carbonate and rabbit skin glue, typical of the preparatory layer of many painted works, and an acrylic-based gesso film were imaged by focused ion beam (FIB) scanning. The gessoes were milled and scanned with gallium ions serially, in sequential planes orthogonal to the plane of the film. This yielded quantifiable measurements of the fine internal structures at a resolution far higher than previously reported for this type of material. This enabled a greater understanding of the geometry of the internal surfaces, increasing the understanding of the mechanics of capillary flow and diffusive behavior in this extremely common and significant material.

Gessoes are widely used in easel painting as grounds or preparatory layers; in art conservation, gessoes are employed as infill materials to level a loss in the paint surface in preparation for inpainting. The goal of this investigation was to establish the relationship between the mechanical behavior of various gessoes when exposed to different relative humidities (25%, 50%, and 100%) and to compare modern commercial gesso products with a traditional gesso. The materials included two commercial artists’ acrylic gessoes (composed of largely titanium dioxide and aqueous dispersions of acrylic polymers), two commercial spackling compounds frequently used in the conservation of easel paintings, and a traditional gesso (calcium carbonate and rabbit skin glue). Uniaxial tensile testing was used to characterize the elastic modulus, strain at failure, and ultimate tensile strength (UTS) of the materials. By understanding the physical limits of these materials under different conditions, damage to artworks and the failure of conservation treatments containing these types of materials may be prevented or reduced.

In order to model and predict the alteration of medieval potash-containing stained glass, it is necessary to understand the mechanisms of alteration layer formation at the glass surface and its role on the evolution of alteration kinetics. Moreover, the alteration layers observed on stained glasses are particular, as they are often fractured and heterogeneous in terms of thickness, with the appearance of pits and the detachment of scales. Contrary to silicate glasses altered in aqueous environment where the gel layer has a protective role, cracks and scales are harmful to the durability of stained glasses altered in air. In order to address these mechanistic issues, a program of experiments in the laboratory and in the field were performed. The fracturing was shown to be caused by the growth of the alteration layers and amplified by the alternation of humid and dry periods changing the density of hydrated layers. The pitting is initiated by defects at the glass surface and increased in external atmospheric medium as these defects fix the precipitated salts. However, despite fracturing and pitting, the development of an altered layer imposes a diffusive transport of the solution between the external medium and the bulk glass.

Two Cloisonné enamel architectural components from Fuwangge in the Forbidden City that were produced from Yangzhou (one production center) in Qing Dynasty (1616-1911 A.D.) were chosen and analyzed. A combination of Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and micro-Raman spectroscopy was successfully used to analyze eight colors in enamel glazes (yellow, white, pink, turquoise, yellow green, deep blue, red and deep green). Chemical composition results reveal that the enamel glaze matrix belongs to lead-potash-lime glass (PbO-K2O-CaO-SiO2). Based on Raman spectroscopy, lead-tin yellow types II, cassiterite, lead arsenate, fluorite and hematite were found as opacifiers and/or colorants. In addition, a detailed discussion of raw materials, such as fluorite and borax, might provide valuable information to trace manufacturing technology and provenance.

Although widely employed in Eurasia, lead glazes were produced in only two small regions of the Americas prior to European contact, both in the Southwest. Southwestern glaze paints are unique in that they developed as decorative elements instead of as protective surface coatings. The first independent invention of glaze paints was in the Upper San Juan region of southwestern Colorado during the early Pueblo I period (ca. 700-850 CE). Despite recent interest in the later Pueblo IV glaze paints of New Mexico (ca. 1275-1700 CE), there have been no technological analyses of the Pueblo I glaze paints. This research project presents the first analysis and technological reconstruction of the Pueblo I glaze paints. It is in the production of the glaze paints that the potters were innovating and experimenting with materials. These early glaze paints have the potential to provide important information regarding both technology of production as well as the relationships and interactions of potters during this period in the Upper San Juan region. Preliminary results reveal a pattern of traits that involves raw materials, processing, properties and performance of the final product suggesting the existence of a patterned technological behavior.

Black-glazed tea bowls from the Jian area of Fujian province, China, were analyzed to understand the physical basis of their visual appearance and the special glaze effects of nucleation, crystal growth, control of glaze flow, and hare’s fur and spotted patterns that have frustrated modern and ancient factories that are unable to produce acceptable replicas. The black-glazed Jian bowls are divided into two distinct groups called “Hare’s Fur” and “Oil Spot”. Black glazes and bodies from the Jian kilns are rich in iron and calcium oxides, made from a plentiful local refractory dark red clay, and fired in hill-climbing dragon kilns. Twenty-six sherds were analyzed from the collection made by James Plumer at the kiln site in 1935 [1]. Analyses were conducted using optical microscopy, Xeroradiography, scanning electron microscopy (SEM-EDS) and electron microprobe analysis (WDS), and petrographic thin section analysis to reverse engineer some of the microstructure, composition and thermal history of Jian ware.