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.

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.

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.

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.

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.

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.

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.

Preparation, analytical characterization, and crystal structures of N,N′-bis(thiophen-2-ylmethyl)ethane-1,2-diaminium hydrochloride (1) and of its gold derivative, N,N′-bis(thiophen-2-ylmethyl)ethane-1,2-diaminium tetrachloroaurate(III) (2) are reported. Compound (1) was obtained by reduction of the Schiff base N,N′-bis(thiophen-2-ylmethyl)ethane-1,2-diamine followed by HCl solution addition, whereas compound (2) was prepared reacting (1) with K[AuCl4] in aqueous solution. Compound (1) crystallizes in the orthorhombic system with space group Iba2 and cell parameters a = 29.856(1), b = 5.1372(2), and c = 10.1635(4) Å. Crystals of (2) belong to the monoclinic system with space group P21/c and cell parameters a = 11.0829(1), b = 9.5852(1), c = 11.6054(2) Å, and β = 75.49(1)°. Both structures contain diprotonated organic moieties, counterbalanced by hydrogen-bonded Cl−, or [AuCl4]− ions, in compounds (1) and (2), respectively.