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Master's-level students complete their second-year science coursework in the newly-renovated (Summer 2018) Scientific Research and Analysis Laboratory (SRAL). The second-year science curriculum, offered during two contiguous semester courses, addresses the basic theory, procedures, and capabilities/limitations associated with the spectroscopic and chromatographic techniques most commonly encountered in collections interpretation and art conservation research. Learning goals focus on understanding and using recent scientific journal publications.
These courses enable our students to gain hands-on experience in data collection, interpretation, and evaluation for a range of instrumental techniques, including Raman, x-ray fluorescence (XRF), x-ray diffraction (XRD) and Fourier-transform infrared (FT-IR) spectroscopies, gas- and liquid- mass chromatography (GC- and LC-MS,), pyrolysis GC-MS, and scanning electron microscopy with x-ray microanalysis (SEM-EDS). Students also have access to instrumentation at the University of Delaware. For example the Advanced Materials Characterization Laboratory, the Mass Spectrometry Facility and the Surface Analysis Facility. This experience familiarizes our students with scientific methodology, proper sample preparation procedures, the challenge of accurate data interpretation, and current research in the field of cultural heritage science. A year-long materials research project (previously a Technical Study) ensures that our students have working familiarity and hands-on experience with instrumental methods of analysis as they relate to the activities of collections interpretation and conservation.
Many of these projects have contributed new scholarship to the understanding of unusual cultural materials, treatment procedures and preventive practice. The ultimate goal of our second-year science curriculum is to produce conservators who will work as informed collaborators with scientists. This year's research projects include the technical study of a paper doll house, research of a Fraktur birth and baptismal certificate, determination of the fungistatic and fungicidal effect of linalool on textiles, a study of the impact of benzyl alcohol on oil paint films, an investigation of works by Joachim Patinir and other Netherlandish painters, the scientific analysis of a Tafsir manuscript and leather case from Gambia, the characterization of nontraditional paint media in one of Robert Rauschenberg's paintings, the technical analysis of a blue Japanned chair attributed to Giles Grendey, an analytical and archival investigation of Robert Rauschenberg's Borealis metal paintings, and the study of artistic techniques and materials in a 19th-century monochromatic drawing.
Dr. Jocelyn Alcantara-Garcia, Dr Rosie Grayburn, and Catherine Matsen provide student supervision and instruction in the Scientific Research and Analysis Laboratory. They are assisted by SRAL volunteers Dr. Chris Petersen and Dr Judy Rudolph.
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Ivory belonging to Proboscidean species has long been characterized by Schreger lines. However, differentiating between Proboscidean species is exceptionally challenging. Two extinct species of Proboscidea - mastodon and mammoth – are often indistinguishable if molar teeth or DNA are absent. Two fossilized specimens of fragmentary tusk ivory – from Winterthur and Wharton Esherick Museums - are believed to belong to the species Mammut Americanum. To acquire a firm species identification, surviving Type I collagen was analyzed via peptide mass finger printing (PMF) using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and Raman spectroscopy (Raman). Peptide masses were analyzed empirically, compared to published standards, and were found to likely be mastodon. A spectrum collected from previous Raman analysis was intended to further confirm species identification of the Winterthur specimen; however, the lack of a standard sample did not allow for adequate analysis of the spectrum. Future investigations with a sufficient Raman standard sample and utilization of a solid-phase extraction (a C18 ZipTip®) for peptide purification would provide a more definitive identification of both fossilized ivory specimens.
Disclaimer: This is not OB's abstract but the introduction because OB was unable to complete the work due to unexpected circumstances. Limestone is one of the most abundant sedimentary rocks on our planet. Throughout history—and prehistory—limestone has been used by humans. It has been chosen as a building material and to be shaped into tools and aesthetic objects not only because of its abundance, but also because of its physical qualities. Limestone is relatively soft, yet hard enough to hold finely carved details. These desirable properties also make limestone susceptible to damage from sudden physical forces and gradual erosion caused by mechanical and chemical processes. For architectural and aesthetic limestone, sudden failure as the result of cracking or breaking is likely the most catastrophic type of possible damage. In a linear elastic solid like limestone, classical fracture mechanics predict that if the stress intensity factor (KC) at the tip of an existing defect or crack is below a critical value—defined as fracture toughness (KIC), or a material's ability to prevent crack growth—the crack is stable and will not propagate. The KIC of a material is dependent on the inherent mechanical properties of solid materials defined by Young's modulus and Poisson's ratio. Once the KIC of a material is exceeded, it will rapidly fail. In a perfectly brittle material, a crack can theoretically grow at the speed of sound. Because all materials have some degree of ductility, for a propagating crack to travel at this speed, specific and uncommon conditions are required. In most occurrences, cracks in materials stressed past their critical KIC still propagate at a rate instantaneous to human perception.While brittle failure is the most dramatic type of crack growth, there is a second variety of cracking that can occur at conditions far less extreme than those necessary to cause it. This type of cracking, called subcritical cracking, develops relatively slowly and often goes unnoticed until it causes brittle failure by lowering the material's KIC. Subcritical cracking can occur in stone at stresses as low as 0.05KIC at velocities as low as 10-9 m/s. It can be cause by chemical processes as well as physiomechanical stresses introduced by static loading, cyclical loading, and thermal loading. While all these factors can contribute to the propagation of subcritical cracks, KC remains the most important variable for propagation.
Conservators often grapple between wanting to preserve evidence of use for future researchers to gain context about objects and wanting to remove staining due to the often-irreversible degradation it can cause. To emphasize the evidence of use within objects, this study explored several different sampling techniques including solvent extractions, fiber extractions, and direct sampling on several artificially aged samples made of oily, proteinaceous, and aromatic cooking materials. These techniques were compared to find the technique that would obtain the most amount of sample in the least destructive manner. With these samples, this study explores the efficacy of Fourier Transform Infrared Spectroscopy (FTIR), Gas Chromatography-Mass Spectrometry (GC-MS) and Peptide Mass Fingerprinting (PMF) on food-related stains found within paper substrates. All three solvent extractions (chloroform, acetone, and isopropanol) provided ample sample for FTIR analysis and results suggested they were of a broad oil or fat category. Fiber extraction provided the most amount of data for GC-MS including several fatty acids indicative of plant-based cooking oils. PMF was relatively inconclusive, with possible collagen markers for egg whites and yolks, but no other collagen or keratinaceous material was found. With this information, a case study was performed on Winterthur Library's The Art of Cookery by Hannah Glasse, yielding similar results.
Cold environments have been recommended as a storage practice for many unstable materials as well a method for pest remediation. While these cold storage solutions have been tested and proven effective for many materials, such as photographs and textiles, analysis of common conservation adhesives after freezing and thawing has yet to be studied. Four groups of PVA samples, cured PVA, frozen and thawed cured PVA, artificially aged PVA, and artificially aged frozen and thawed PVA were analyzed through Fourier-transform infrared spectroscopy and thermal desorption–gas chromatography–mass spectroscopy to determine any changes to the adhesive. FTIR revealed degradation to the adhesive through the broadening of the carbonyl peak, while thermal desorption revealed no explicit observations due to variability in the results. Exploring the materiality of PVA has opened the door for better understanding of the materials that conservators use every day.
This research encompasses the first analytical investigation of Robert Rauschenberg's water-based inkjet transfer works made between 1992 and 2008. These works are inherently vulnerable to fading because they were made with light-sensitive colorants and utilized inkjet printing technologies in non-traditional ways. The 497 inkjet transfer works currently in the Robert Rauschenberg Foundation's (RRF) collection make up at least twenty percent of their holdings. An understanding of the sensitivities of the colorants will aid the RRF in making informed decisions about the artworks' display and care. Two works from the RRF study collection, Jaywalk (Anagram) (1996) and Traffic Grooming(Runt) (2007), were chosen as case studies for visual analysis under ultraviolet and infrared light, along with the use of a HIROX digital microscope. Fiber optic reflectance spectroscopy (FORS) was conducted to compare colorants used within a composition. XRF was conducted to gain elemental information about the colorants. FORS and XRF results characterize the composition of the colorants as synthetic organic. Raman spectroscopy is needed to further identify the organic colorants. However, due to the complexities of Rauschenberg's working process, identifying the chemical composition of the colorants may not be the most effective method of understanding and predicting their fading.
This project examines a pendant made by Black American jewelry artist Bob Jefferson (1943-?) through exploring the materials and techniques used by the artist. This piece was made in 1968and is owned by the Museum of Art and Design in New York City. This analysis provides a casestudy of the materials of cultural heritage used in the Black Diaspora. X-ray fluorescence (XRF) was used to gather information on the elemental compositions of the materials present in the object.Raman was used for further analysis of the gem material used in the piece by comparing its spectrum to to jade-type samples in reported in previous scholarship. Stereomicroscopy was used to image the surface topographies and tarnishing on the different surfaces.I investigated how the artist created the work, identified the materials used to create it, noted any corrosion or tarnishing evident on the metal, and investigated the gem material. The findings to date indicate that the gem material present is a form of nephrite, which is a variation of jade that was most likely heat-treated to darken the color. The two main metal components, the bars and the central bell-like component, were crafted using two types of metalworking.The central piece was cast in bronze, and the bars were forged using an alloy similar to jewelers' brass or red brass. A gold and silver alloy was plated on top of the metal.
The limited publications in Spanish and English dedicated to the conservation survey and material analysis of Spanish Patents of Nobility constrict understanding their structural characteristics and preservation needs, leaving collections ignored. Aiming to alleviate the knowledge gap, an 18th-century velvet-bound illuminated Spanish Patent of Nobility was studied. Bilingual historical research and a combination of non-to-minimally-destructive instrumental analysis included: Ultraviolet and Infrared photography; X-ray fluorescence, Raman, and Fourier-transform infrared spectroscopies; Fiber optics reflectance stereoscopy; Polarized light microscopy; quantitative analysis; and Peptide mass fingerprinting. Results suggest the presence of a silk velvet “bookcloth," metalogallic writing inks, smalt-containing Dutch and non-smalt-containing Spanish paper, sheep, or calf parchment, and illuminations of a limited pigment palette including vermilion, lead white, azurite, ultramarine, verdigris, and amalgams of semi-precious metals. This work provides the groundwork for the materiality of similar Iberian legal manuscripts, thus supporting their preservation while hinting at the hierarchical use of pigments, writing supports, and gilding techniques. The subsequent steps of this ongoing project include crafting preservation, handling, and housing guidelines, emphasizing user safety (as toxic metal salts are present on the velvet fabric and paper) while deepening worldwide understanding of analogous Spanish manuscripts, promoting their access within and outside American libraries.
Over the last twenty years, the use of rigid polysaccharide gels has grown in all specialties of art conservation. These gels, most commonly gellan gum and agarose, can provide cleaning solutions in a localized and controlled fashion. In textile conservation, these gels are used in replacement of immersion wet cleaning for fragile or fugitive textiles. However, there is no consensus on the correct way to rinse the cleaning residue from these gel treatments. A rinse gel of pure DI water may be the answer to this problem and would create a convenient and safe way to rinse these fragile textiles. A 1% Orvus solution was made into 1%, 3%, and 5% agarose gels and applied to a plain-woven cotton fabric. No Orvus reside could be detected on any of the samples; the conclusion was that a rinse of any kind is not needed for Orvus gel application.
Vacuum cleaning is both irreversible and exceedingly common in the preservation and conservation of textiles, yet vacuuming methodology and efficacy is under researched. This study set out to compare the efficacy of five vacuuming techniques in removing particulate soiling from a naturally aged linen fabric. Four particulate soiling media were tested: calcium sulfate, iron oxide, zinc oxide, and a mixture containing all three. Cleaning efficacy was evaluated by digital microscopy, micro-X-ray fluorescence (micro-XRF) mapping and photography under visible and ultraviolet radiation. Results show dramatic differences in cleaning outcomes across vacuuming methods and small but significant differences across soiling media. Screen overlays, Vellux overlays, and brush-aided techniques consistently produced somewhat poor results. Brushing embedded soiling further into the textile. An air rocket blaster (air puffing tool) consistently produced the best results, and direct vacuuming with a round dust-brush attachment also cleaned well.
Instrumental analysis is necessary to understand and interpret Japanese Edo period lacquered and painted objects with limited provenance. A Japanese Buddhist portable shrine or zushi from the University of Pennsylvania Museum of Archaeology and Anthropology was the object of technical analysis and subsequent conservation treatment. This study aimed to use analytical and imaging techniques to identify key markers in the lacquer, ground, and preparatory layers; a preliminary assessment of pigments; the construction of the shrine; and elemental analysis of the metal hardware and gold interior. The zushi was analyzed with ultraviolet light; energy dispersive x-ray fluorescence, x-radiography, scanning electron microscope with energy dispersive spectroscopy, Raman spectroscopy, and pyrolysis gas chromatography mass spectrometry. Elemental analysis of the paint and gilded hardware are consistent with Edo period [close up]materials, and markers for thitsi present in the lacquer suggest an economical use of lacquer in Japan. Information gathered from this shrine can be fundamental in interpreting the other Japanese shrines from the same collection.
While studies have shown its suitability and efficacy as a cleaning material, agar is often seen as a temporary material, not something where longevity is desired. In recent years, agar has been explored more widely as a bioplastic, a class of materials becoming more ubiquitous every day and which have made their way into the art world. Museums with design collections have begun acquiring bioplastics and are coming face to face with the reality of how to care for these materials. There is little research into the long-term stability of agar in its dried form. This research aimed to evaluate the stability of art made from agar by examining the long-term effects of a typical museum environment (controlling temperature and relative humidity) on lab and food grade agar, using artificial aging, visual observation, thickness measurements, colorimetry, Fourier Transform Infrared Spectroscopy (FTIR), and Pyrolysis Gas Chromatography-Mass Spectrometry (pyGC-MS). The results of this study helped inform whether agar is a viable material option for loss compensation of glass. After artificial aging, agar experienced significant and undesirable physical changes which were detectable both with and without instrumentation. Chemical changes were not detected by instrumentation. The notable changes in color and thickness of agar caused by aging would be problematic for artworks made of it, and if it were to be used as a conservation material.
Persian lacquer pertains to a wide range of lustrous decorative wares created by layering varnish and paints. This paper will focus on the outcomes of analysis performed on a pair of lacquered book boards which cover a manuscript from the Free Library of Philadelphia treated by WUDPAC student Rachel Bissonnette. There is currently a lack of analytical research on Persian lacquer that highlights a need for this study. Persian lacquer objects have often been grouped with the more well-known and well-studied East Asian and European (or Japanned) lacquer objects. This reductive classification disregards the unique stratigraphy and materials used in the creation of Persian lacquer. There is a danger in not fully understanding the manufacture and composition of these objects; a conservator without an understanding of the materiality could make an inappropriate treatment decision. Cross-section microscopy, scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDS), Fourier-transform infrared (FTIR) microspectroscopy, and pyrolysis-gas chromatography/mass spectrometry (Py-GCMS) were performed to identify the materials and techniques used to decorate the book boards. The results of this study help to contextualize Persian lacquer in its own tradition and provide a framework for continuing to grow the technical understanding of Persian lacquer.
Obtaining more knowledge on the cultural exchange of cap-mask-related practices throughout the Cross-River Region of Nigeria and Cameroon is possible through analysis and identification of skin-covered cap mask materials. The object of this technical study is a dance crest and headdress from Bryn Mawr College attributed to the Ejagham people from the Cross-River Region in Nigeria and Cameroon. Often referred to as cap masks, they were traditionally used in coming-of-age ceremonies, celebrations, and funerary practices. This technical study aimed to identify the skin, wood, and horn materials as well as to examine the general construction techniques using a multi-analytical approach. The mask materials were identified as two blackbuck horns, one unidentified horn, skin from the blue duiker or Bioko blue duiker that has no additional surface coatings, and a diffuse porous tropical hardwood. Further research opportunities include applying similar analytical methods to larger collections of Cross River Region skin-covered masks and collaborating with cultural heritage workers in Cameroon and Nigeria.
Orvus WA Paste is primarily composed of the anionic surfactant sodium lauryl sulfate and is widely used by textile conservators in North America. This study examines the comparative rinsabilities of Orvus WA Paste on cotton and wool, two commonly bathed fiber types in North American collections, as well as the long-term effects of Orvus residues on these two materials, using accelerated aging, colorimetry, tensile strength testing, vertical wicking tests, and scanning electron microscopy before and after aging. The findings suggest that Orvus residues are innocuous on cotton and wool. If confirmed by further research, this could have impacts on the environmental and financial sustainability of textile wet cleaning.
Anoxic, or oxygen-free, environments can help in the long-term preservation of rubber. However, the implementation of anoxia is sometimes forgone due to concerns of sustainability and feasibility, especially if the rubber object is large. The question of whether anoxic storage is an effective preservation storage solution for tire rubber is explored through comparing the condition of artificially aged automobile tire rubber stored with AGELESS® oxygen scavenger and without. Condition is assessed through visual examination, two methods of headspace SPME-GC-MS, and liquid extracted GC-MS. Some of the data demonstrates that anoxia did have an effect on the tire rubber. This study helps establish an experiment that can be repeated to create a greater wealth of data on the efficacy of anoxic storage for rubber.
This investigation sought to provide a better material understanding of a painted horn lantern shade estimated to be produced in China sometime in the late 18th/early 19th century CE. There is little information about the production of these horn lanterns, and few extant examples. A technical investigation of the horn and paint would provide more information about the materials available and used to create such an object. One reliable method of analysis to identify the animal origin of a proteinaceous material such keratinaceous horn is peptide mass fingerprinting (PMF) via matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-ToF MS). The preparation of a keratin sample for MALDI-ToF MS has not previously been carried out at Winterthur, and the execution of this research contributed to the establishment of a new analytical protocol for the Scientific Research and Analysis Laboratory (SRAL). The keratin analysis was largely inconclusive, but the paint analysis revealed the presence of a 20th-century synthetic pigment, moving up the estimated manufacture date significantly.
As an understudied material, nineteenth-century bookcloth holds a wealth of knowledge that only recently has impacted its conservation as well as the health and safety of library staff and patrons. A combination of non-destructive and minimally invasive analytical techniques, including visual examination under magnification, fiber and pigment identification using polarized light microscopy (PLM), X-ray fluorescence spectroscopy (XRF), Fourier-transform infrared spectroscopy (FTIR), and Raman Spectroscopy was used to analyze a sample set of eleven nineteenth-century publishers' bindings from the study collection of the Library Conservation Lab at Winterthur Museum, Garden & Library. Results suggested that all of the bookcloths were made from a plain-weave cotton textile, and all contained detectable amounts of lead and iron. Other elements such as copper and calcium were detected, and many of the samples contained wheat starch and animal glue. Only four samples had detectable pigments: ultramarine, Prussian blue, and chrome yellow. While all the materials characterized are consistent with those cited in historical literature, these results cannot definitively confirm the precise use of each material.
Magnesium and its alloys are highly desirable structural materials with a propensity to corrode. Used in a variety of industrial applications since the early 20th century, magnesium alloys can be found in objects ranging from automobiles and satellites to consumer electronics and appliances. Many of these objects have found their way into both museum and private collections, providing a unique opportunity for conservators to consider industry standards in the mitigation of magnesium corrosion. This study considered the industry-proven effectiveness of conversion coatings in the treatment and prevention of magnesium corrosion and investigated the conversion coating process from a cultural heritage perspective. Placing ethics and the preservation of original material at the forefront, this study focused on evaluating the effects of proprietary pre-treatment acid-baths on the surface of a corroded magnesium alloy with a worn conversion coating. As acid-baths are an essential part of the conversion coating process, this study assessed different application methods for the pre-treatment bath – comparing a conservative localized approach to full immersion of the samples. Analysis was conducted using scanning electron microscopy-energydispersive x-ray spectroscopy, x-ray diffraction, and digital microscopy. Results of the study supported the use of immersion treatment as it produces a more effective coating.
The small genre scene titled Peasants at Day's End, has an unknown date and attribution. Dendrochronology performed prior to this study dated the oak substrate to the 1500s. The composition appears to be based on a 17th-century etching by David Teniers the Younger (1626–1690). A technical study was carried out in order to compare the pigments and binders identified to those used by 16th-17th-century artists. Cross-section analysis, energy-dispersive x-ray fluorescence (XRF), scanning-electron microscopy–energy-dispersive x-ray (SEM-EDS), Raman spectroscopy (Raman), Fourier-transform infrared (FTIR), and pyrolysis-gas chromatography/mass spectrometry (Py-GCMS) were all used in order to characterize materials. The chalk-glue ground and oak substrate are consistent with early Dutch panel paintings, but the Prussian blue identified in multiple layers places the earliest date to 1720. A 47-millimeter square scanning XRF map found no indication of an earlier painting under the present composition.
There is significant anecdotal evidence of private clients placing artworks in their residential baths as décor. However, there is no previously published data on the effect that a running shower has on the temperature and relative humidity of a space and how it may impact nearby objects. High relative humidity and fluctuations thereof have a negative effect on many materials; this research shows that taking showers causes ambient relative humidity to increase in the bathroom and adjacent rooms. This microenvironment increases the rate of degradation of many materials, including those commonly used in artwork or décor. Materials that are sensitive to fluctuations in relative humidity or condensation on the surface will likely react or degrade more quickly if displayed in a room with a shower. The goal of stating this is not to dissuade people from decorating their homes as they like, but rather to inform decisions about display location for special or sensitive objects.
A technical study of Selva con Atardecer (Jungle with Sunset) by the Venezuelan artist Feliciano Carvallo (1920–2012) was conducted in order to characterize the materials used on the painting. Understanding the paints and materials used will increase the current scholarship about mid-to-late 20th-century Latin America artists and paint manufacturers in addition to the artist's working techniques, materiality, and the aging properties of his works. Analytical techniques utilized included X-ray fluorescence spectroscopy (XRF), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), and Gas Chromatography-Mass Spectrometry (Py-GC/MS) to gather relevant organic and inorganic information about materials used. A combination of alkyd and oil paints with organic synthetic pigments was identified as the painting medium with a two-ground preparation of lithopone, titanium dioxide, and calcium carbonate as the ground. The study found the remnants of a coating to have gum Arabic and agar-agar present, further research and connoisseurship will be needed to determine if a coating was originally desired by the artist.
The materials of an early 20th-century Negidal fish skin bag (fish skin, feathers, fur, fibers) were assessed with peptide mass fingerprinting (PMF) using matrix-assisted laser desorption/ionization with a time-of-flight mass spectrometer (MALDI-TOF) and x-ray fluorescence (XRF) to determine the species or family identification of the furs, skins, and feathers wherever possible, and to learn more about the presence of inorganic components such as pesticides and mordanted dyes. The feathers and fur could not be definitively identified due to lack of published PMF references for biomarkers. The fur, however, has diagnostic PMF markers associated with the Mustelidae family (Daniel Kirby, email message to author, January 24, 2020). The fish skin was identified as belonging to the Salmonidae family, although the species of pacific salmon remains inconclusive (Kristine Korzow Richter, email message to author, February 27, 2020). These limitations highlight the need to expanded Siberian fur, fish and feather reference materials for PMF. XRF indicated the presence of bromine and arsenic, which were likely applied as pesticides and thus informed safe handling. Further research on early 20th-century indigenous Siberian dye technology is needed to characterize inorganic dyes or mordants on the object based on the XRF data collected in this study.
Plasticized polyvinyl chloride, or PVC, is one of conservation's most common and problematic materials. PVC is of the infamous “malignant" plastics whose autocatalytic deterioration mechanism will damage both the object itself and others stored with it. This inherent instability is primarily due to the plasticizers added to the rigid polymer. As the PVC degrades, plasticizer leaches out of the polymer matrix and deposits on the surface, creating a damaging, tacky layer on cultural heritage objects. Consequentially, aqueous cleaning is a common conservation treatment to remove the migrated plasticizer. However, it has been suggested that its removal may cause additional plasticizer to leach from the polymer matrix, essentially exacerbating deterioration over the long term. To explore this question, samples of naturally aged PVC exhibiting heavy plasticizer migration were analyzed with Fourier-Transform Infrared Spectroscopy and visual examination. Experimental groups were then cleaned with either deionized water or a non-ionic surfactant. Cleaned samples were placed in a Q-U-V Accelerated Weather Tester for 400 hours of UV exposure to approximate forty years of museum exhibition, and then examined visually after aging. After exposure to UV light, all samples exhibited increased plasticizer migration with limited microcracking. Preliminary results were inconclusive as all samples exhibited similar characteristics. At this time, it cannot be determined if aqueous cleaning has an effect on the migration rate of plasticizer. Additional analysis before and after aging – Pyrolysis-Gas Chromatography-Mass Spectrometry to characterize the plasticizer and sample weight and Thermogravimetric analysis to quantify it–may provide further information.
Understanding the materials used in collections storage is incredibly important to the preservation of cultural heritage. These materials must serve a functional purpose without inducing damage caused by the emission of harmful pollutants from the materials themselves. Although there is no published research on the use of Dartek® C-917 film for long-term collections storage applications, it is commonly used in this context as a dust covering for all manner of objects. This paper describes “Phase 1" of two-part investigation of Dartek® C-917. Fourier-transform infrared spectroscopy and pyrolysis-gas chromatography/mass spectrometry were used to classify the material as a Nylon 6,6 film. Data gathered in these tests will serve as a baseline for “Phase 2" of the investigation, which will analyze the effects of heat-ageing and exposure to acidic conditions on the chemical properties of the film.
In art conservation and collections care, certain tested materials are commonly used for housing, storing, and exhibiting cultural heritage objects, yet many institutions with significant collections worldwide are unable to sustainably acquire and rely on these materials. Collection stewards may be left guessing whether their storage systems are safe or not as they rely on untested alternatives to conservation-grade materials such as “blue board" and “buffered interleaving." In Iraq, collections housing materials must be purchased from non-conservation suppliers such as stationery stores and markets. For this study, the Iraqi Institute for the Conservation of Antiquities and Heritage prepared samples of locally available materials typically used in collections housings. Eight materials were characterized by Fourier transform infrared spectroscopy and the Oddy Test. All samples were rated “passing" by the Oddy Test, and the materials were tentatively determined to be polyethylene, polyester, and Nylon by FTIR analysis. Additional testing and contextual information about the application of these materials is needed to make recommendations about their use in collections care.
Eighteenth- and nineteenth-century artists and restorers used poisonous materials in their work including copper-arsenic-based green paint and lead-based adhesive. Present-day conservators take health precautions and assess the risks these materials pose to museum visitors, but first the poisonous materials must be identified. Emerald green is difficult to characterize visually because it discolors through reactions with airborne sulfides. Lead-lined paintings are described in few publications making noninvasive identification challenging. The double-lined painting Still Life with Flowers exhibited some characteristics of copper- arsenic-based green pigment and a lead-lining. The aim of this technical study was to use X-ray, XRF, MA-XRF, PLM, FTIR, and GC-MS to corroborate the presence of emerald green paint and lead-based adhesive in Still Life with Flowers and to inform subsequent conservation treatment. The results substantiate the presumed date of creation and allowed for a more detailed narrative of the object's history to be formulated.
Books bound in leather that have become friable and powdery is a common problem in libraries. Commonly referred to as “red rot," this specific type of leather deterioration is caused by hydrolytic and oxidative deterioration mechanisms. Leather “dust" dirties library stacks, reading room tables and book cradles, and the clothes of the user. Red rot signals the end of the deterioration mechanisms; thus, conservation treatment cannot stop or reverse this deterioration. Therefore, conservation treatment of red-rotted leather is limited to surface treatments such as consolidation, a treatment that can either be the only treatment of the leather or the first step of a more invasive treatment. Cellulose ethers were first used in conservation treatment in the 1970s and their use continues in book conservation and other specialties. Cellulose ethers are made through an esterification process which dilutes the cellulose with “the esterifying groups so that the final product contains only a proportion of the starting cellulose structure." Hydroxypropyl cellulose (a form of which is commercially sold and known as Klucel-G) is esterified with propylene oxide. Klucel-G is used widely in book conservation to consolidate red-rotted leather. Although, Klucel-G is often used in conjunction with other materials such as waxes, this research will study the penetration of Klucel-G into the leather substrate and the mechanical properties of leather coated with Klucel-G with the aim of better understanding how Klucel-G penetrates the leather substrate, and if and, more importantly, how the level of penetration affects the mechanical and physical properties of the leather. The mechanical tests proposed to be used in this study were chosen in an attempt to simulate the stresses leather-bound books experience during their use. Studying how Klucel-G may affect the mechanical properties of books is especially important as books must continue to function following conservation treatment. This study aims to add to the growing literature which connects material-related scientific study to the practical use of materials in day-to-day conservation practice. (Note: This student was unable to carry on the project because of the pandemic restrictions.)
A material investigation of a Crucifixion panel painting from Bryn Mawr College aimed to explore the work's estimated attribution to the workshop of Italian Renaissance painter Cosimo Rosselli (1439-1507)—an attribution previously assigned by art historians based on stylistic observations. A combination of noninvasive and minimally invasive analytical techniques—including X-ray fluorescence spectroscopy (XRF), fiber optic reflectance spectroscopy (FORS), Raman spectroscopy, cross-section analysis, and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS)—was therefore carried out to examine the organic and inorganic components of the Bryn Mawr Crucifixion. Results suggest the presence of a calcium sulphate ground applied in two distinct layers, what appears to be a carbon-based underdrawing, and a paint film composed of a limited palette of pigments: lead white, iron earth oxides, vermilion, red lake, ultramarine, and copper-based blue and green. Reflectance spectra generated through FORS additionally suggest an egg yolk component of the paint binder. In comparing these results to previously published technical studies of Italian Renaissance paintings, all materials characterized and suggested by this analysis appear consistent with those traditionally used in Italy around Rosselli's time. This deeper material understanding of the painting provides evidence that supports its previous attribution to an Italian Renaissance workshop; however, a precise authorship or date for the Bryn Mawr Crucifixion cannot be concluded from these results.
Despite their presence in the libraries of the United States, traditional Korean bindings are absent in the analytical literature. There are needs in analyzing the attributes of Korean bindings to preserve and conserve these bindings appropriate to the culture. The three Korean books, approximately from late nineteenth to early twentieth century, were closely examined with a series of analytical instruments to characterize the materials used in the bindings. The major findings were on the construction of the cover and text papers and their properties through a combined use of stereomicroscope, polarized light microscope (PLM), and scanning electron microscope (SEM). Although this project was shortened due to COVID-19, the three books were clearly identified as having Korean bindings with evidence on how they were constructed and processed.
Rabbit skin glue is often indicated as a preferred binder for the preparatory layers in traditional water gilding and as a treatment material in gilded objects conservation and restoration, but previous studies have suggested that references to this material are mostly absent from pre-twentieth-century recipes, treatises, and literature and that some modern preparations sold as “rabbit skin glue” may in fact be generic animal collagen glues. Four commercially-available products sold as “rabbit skin glue” were analyzed by peptide mass fingerprinting (PMF) with matrix-assisted LASER desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) in order to characterize their proteins and suggest a species- or family-specific animal source. Three of the products analyzed had protein fingerprints consistent with cattle, with no indication of any protein mixture, while one product had a protein fingerprint consistent with a mixture of proteins, likely cattle protein and another undetermined animal proteins.
A Hardanger fiddle (Hardingfele) made by John Eriksen Helland in Norway in 1833 with rare surviving intact original surface decoration provided an opportunity to characterize materials specific to a musical instrument with a known maker, region, and time period. The eye-catching decoration on the wood body, including parquetry veneer, ink drawings, metal leaf and size, paint, and surface finish were characterized using microscopy, spectroscopy including µXRF and FTIR, and mass spectrometry including GC-MS and MALDI-TOF-MS. Spruce and black alder woods, horse-bone veneer, iron ink, brass leaf with a drying oil size, iron oxide paint in a shellac and drying oil binder, and a varnish of shellac and a drying oil were all identified. Novel material identifications for Hardanger fiddles were made, including the characterization of the metal leaf, ink drawings, and paint pigment and binder. Further, some characterizations conflict with the popular lore for these instruments, including the identification of horse bone and the inclusion of a drying oil in the varnish. This study contributes insight and nuance to the history of Hardanger fiddles, providing material context for this musical instrument.
The object in this study is a Victorian scrapbook house or paper doll house, which is a unique object from the Winterthur Library Grossman Collection and has an unknown provenance. The scraps used for composing the paper doll houses are of variety types of materials that are ephemeras such as chromolithograph, pigment-coated paper, Dresden trims and photographic prints. Such mass-produced materials during the late nineteenth century have been much understudied. Two pages from the scrapbook were selected to be examined and instrumentally analyzed to determine if the object contain potential hazardous materials and if the study could narrow the date range of the object. Hazardous inorganic materials including lead and arsenic were identified by surveying elemental composition using XRF. Some inorganic colorants and the stratigraphy of some pigment-coated papers were studied using Raman, FT-IR, cross-sectional analysis, and SEM-EDS.
The Fraktur palette was long believed to be composed of home-made media. Scientists and conservators from the Winterthur Museum began work to dispel this notion in the late 1970s. Their work has been carried on by subsequent generations of Winterthur staff and students, and this study aims to contribute to the growing knowledge surrounding Fraktur artistic practices. X-ray fluorescence (XRF) was used to identify the elemental composition of pigments, ink, and paper which then guided the use of supporting instrumental analyses. Raman spectroscopy was used to identify Prussian blue and carbon black, both previously identified as Fraktur pigments, as well as red and yellow lead. Synthetic pigments PR49-2 and PG-16 were also identified using this technique and could provide further insight into 20th-century restoration practices. Green pigment and binder media remained inconclusive despite testing with X-ray diffraction (XRD), Raman, and Fourier-transform infrared spectroscopy (FTIR). The study adds to previous efforts to narrow the wide range of materials potentially used in Fraktur decoration, while identifying areas in need of further study. Understanding the materials involved in the making of this illustrated document will inform future decisions regarding its preservation, as well as contribute to the growing resources compiled by conservators and researchers that are so crucial to understanding the mechanics at play.
As global temperatures rise and major weather events become more frequent, the risk for mold outbreaks in cultural heritage collections increases. In order to prevent mold growth, we rely heavily on energy-intensive mechanical systems to control the temperature and relative humidity, which is unsustainable and contributes to climate change. Terpenoids, such as linalool, found within essential oils are continually being examined for their fungistatic properties, and they may also be regularly found near cultural artifacts due to their common presence in fragrances. For this research, linalool was confirmed as a fungistat on inoculated and incubated woven cotton textiles. Additional cotton and silk textile samples were exposed to linalool to determine if the compound contributed to the degradation of the fibers. Due to the linalool compound's allylic structure, it can easily form hydroperoxide products, which may be damaging to objects. A multi-analytical approach was used to determine if there are any deleterious effects on cotton and silk textiles exposed to linalool vapors by comparing aged and unaged samples. Fourier Transform Infrared Spectroscopy was used to look for key absorbance peak ratios that confirm oxidation degradation in the fibroin proteins of silk. The results suggest that linalool may have helped to protect the silk fiber from oxidation during artificial aging using high temperature and relative humidity, and other analytical techniques used were not showing a significant change in the textiles exposed to linalool.
Benzyl alcohol is currently a popular active reagent in aqueous and solvent-based gelled emulsion systems for the cleaning of easel paintings. A case is made to broaden the scope of active reagents to benzyl alcohol derivatives, compounds that retain the benzyl alcohol core, but that incorporate additional functional groups at either the para-, meta-, or ortho- positions on the aromatic ring or at the benzylic carbon. This report presents initial forays into employing a single benzyl alcohol derivative, 1-phenylethanol, in aqueous gel cleaning systems and evaluating its effect on the original paint film. These results are compared to the effects of a control gel consisting of benzyl alcohol as its active ingredient. Both active ingredients were gelled as 10% w/w solutions in a pH 6 xanthan gum carrier. Effects on the original paint film were evaluated using SEM to qualitatively document surface morphology changes and to measure thickness changes in cross section. GCMS was used to quantitatively compare amounts of leached low molecular weight organic compounds. From the cleaning tests, the benzyl alcohol gel appears to work faster than that of the derivative. However, the two generally result in similar surface morphologies when visualizing at magnifications up to 3800X in SEM. SEM thickness measurements revealed the benzyl alcohol cleaned areas had markedly thinner paint films, a result that aligns with the observation that the benzyl alcohol gel is a stronger swelling agent of the original paint film compared to the derivative. GCMS analyses qualitatively furnished extracts expected from aged oil films, but the resulting data from quantitative comparisons of leached palmitic, stearic, and azelaic acids showed no consistency. This likely reflects errors in experimental design and will need to be repeated in future studies.
Bought at a yard sale for just twenty-five dollars and covered with extensive restoration materials, a Baltic oak panel painting entered the Winterthur Paintings Conservation Studio in January of 2018 with a potential attribution to Joachim Patinir (1480/1485-1524). Although art historically, the painting was determined to be stylistically outside the scope of works within Patinir's oeuvre including works produced by his Workshop, a full technical study was conducted on the original materials present to better understand the broader context, materiality, and techniques present. Multi-band imaging, a range of spectroscopic analyses, and gas chromatography were conducted to obtain both organic and inorganic elemental information about the materials present. Dendrochronology and pigment analysis helped narrow the date of creation to between 1540-1750. Overall, the stratigraphy and materials matched those used by Netherlandish painters including: a double calcium carbonate and silicate-containing ground, likely carbon-based underdrawing, lead-white oil-bound imprimatura layer, and the final thin painted layers with pigments including smalt, azurite, lead white, ochres and iron oxides, vermillion, lead-tin yellow highlights, and discolored verdigris glazes. Continued research into late sixteenth/early seventeenth- century artists should be continued to add to the art-historical body of knowledge surrounding the piece, as well as acknowledging the role that collaborative technical examination can play in assigning authorship.
Due to the lack of scholarship on the proper handling and conservation treatment of Islamic manuscripts in general, and African-made Islamic manuscripts specifically, a scientific and ethical investigation was launched on a 1942/43 tafsir, or commentary on the Quar'an, from Gambia to gain a more complete understanding of its tangible and intangible needs and condition. Multi-analytical and imaging techniques were used to analyze the primary paper and inks of the textblock and leather of the carrying case. The paper was identified as a mechanically pulped bast fiber with a high lignin content and potentially a starch and/or resin-based sizing. In keeping with Islamic religious requirements, no proteinaceous materials were found in the textblock. However, the paper is at a high risk of continued degradation and loss of content making it the primary conservation concern. The principal inks were plausibly identified as red iron oxide and carbon-based black. These inks are in stable condition but are still at risk of loss due to the friable paper substrate. The leather was identified as goat and seems to be in good and stable condition. Though much more research can be done to add to the understanding of this manuscript's informational and artifactual content, the crucial issues of material characterization and condition have been answered satisfactorily enough to create an initial preservation and conservation plan. The most important finding of this research is that the preservation of a religious object's intangible elements is just as important, if not more so, than its physical elements.
Robert Rauschenberg (1925-2008) was an American artist at the forefront of the Neo-Dada Art movement, best known for his Combines made with found objects and his influence on American Pop Art. However, he began his artistic career as a painter at the experimental Black Mountain College in western North Carolina. Here he was influenced by collaborations with many artists, color theory, constructed chance, and the potential of any material to be used as viable media. Rauschenberg created the Night Blooming series of paintings while at Black Mountain. The story of the painting describes the materials and process, which have been described variably and using terminology such as asphaltum, tar, lead paint, red lead, aluminum, oil, and latex house-paint. One of the paintings, RRF 51.016, is the subject of this multi-analytical study. In visible light, the surface exhibits areas of both crystalline and glossy exudites. The analysis revealed the likely presence of bone black and a bituminous component in the thin, overall black paint layer. One other type of carbon-pigment black paint was identified, as well as titanium white (rutile) paint. All paint samples lacked significant drying oil components and contained oxidized pine resin derivatives and a variety of filler material, supporting Rauschenberg's appropriated use of non-artist materials. The results may inform preventive measures and treatment options for this and other modern and contemporary works exhibiting degradation products or condition concerns from the interactions of the material components.
This research encompasses the first analytical investigation into Robert Rauschenberg's Borealis metal paintings (1988-92). Street Song (Borealis) (1990) was selected as a case study to characterize the materials and compare findings with archival records and three items from the Robert Rauschenberg Foundation's Source Materials collection. Samples of the coating, tarnish layers, and metal substrate were taken from Street Song(Borealis) and analyzed with microscopic and spectroscopic techniques to investigate the possible darkening of the metal substrate, tarnish layers, and glossy varnish coating. Non-destructive analysis with energy-dispersive X-ray fluorescence was conducted to determine the composition of the metal alloys and verify the legacy descriptions. Results identify the metal substrates as brass with high zinc content, various copper corrosion species in the tarnish layers, and the varnish as an alkyd-type industrial coating. Preliminary results concerning the tarnish layers indicate that future study with a broader sample set is required to fully understand the implications for long-term preservation.
Technical analysis was conducted on a blue Japanned chair with raised and gilt decoration, which is attributed to Giles Grendey c. 1735, London, recently accessioned by Winterthur/University of Delaware Program in Art Conservation Study Collection. This study on the painted surfaces of the English blue Japanned chair reveals the materials and techniques applied to the chair in the 18th century, which are probably originated from the historical records and recipes from Stalker's and Parker's A Treatise of Japanning and Varnishing in the 17th century, but the modifications and variations suggest more consistency with Dossie's Handmaid to the Arts in late 18th century.
Monochromatic drawings are an often-overlooked folk art that was very popular in the United States from the middle to late 19th century. This technique has been known by many names, including Grecian painting, monochromatic painting, and sandpaper painting or drawing. It was popularized by itinerant artists and how-to guides that detailed exactly what materials to use and how to apply them. There is a current lack of materials research on this type of artwork. Using a multi-analytical approach, the materials of Winterthur Museum's drawing were analyzed, finding that in large part the materials used are consistent with those listed in the historical guides. Among the materials found were lead white, marble dust, and charcoal/carbon black. Discovering what materials were actually used sheds new light on this under-studied art form, informing treatment decisions and helping to ensure its continued preservation for future generations.
An ancient Greek vessel that was donated to Bryn Mawr College did not come with substantiated provenance and was in poor condition due to a failing previous intervention. Analytical techniques including ultraviolet light induced fluorescence (UV), x-radiography, x-ray fluorescence spectroscopy (XRF), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), Fourier-transform infrared spectroscopy (FTIR), gas chromatography-mass spectrometry (GCMS) and inductively coupled plasma-mass spectrometry (ICP-MS) were used to yield more information on the many interactions with humans that it has experienced. Results led to the identification of cellulose nitrate adhesive, the discovery and partial characterization of discontinuous radiopaque features in the clay body, and the supported attribution to its presumed source of the Mediterranean though not the confirmation of its specific country of origin. These results both aided in making decisions for its current treatment as well as added information to be conveyed in its use as a teaching aid and resource at Bryn Mawr College.
There is a significant body of scholarly work on the sculptures of American artist George Gray Barnard (1863-1938), yet very little is published about his works on paper, now held in the University of Delaware (UD) Museum. Barnard was a prolific draftsman who made numerous concept sketches and preparatory drawings related to his sculptures, including one untitled sculptural study with an unusual shiny, golden-brown coating surrounding the main figure. In addition to fiber identification and optical microscopy, instrumental analysis with X-ray fluorescence (XRF), Fourier Transform Infrared Spectroscopy (FTIR), Raman Microscopy, Scanning Electron Microscopy (SEM), Gas Chromatography- Mass Spectrometry (GC-MS), and cross-section microscopy helped to illuminate the elemental and molecular composition of the paper substrate, the drawing media, inks, white pigment layer, and the resinous coating. This analysis has indicated the artist's use of some traditional materials like charcoal, iron gall ink, and gesso, as well as non-traditional art materials like lithopone paint, pine resin varnish, and a small nail that could have been available in his studio or purchased at a hardware store. The artist appears to have used these materials in an interdisciplinary manner, combining the materials and application techniques of a draughtsman, painter, and sculptor, resulting in a fascinatingly complex object likely created as a concept sketch rather than a finished presentation drawing. An increased understanding of Barnard's drawing materials provides insight into his working methods and will answer questions about other drawings in the UD collection. This study also will assist in the future treatment of this object by informing best practices based on its materials and by understanding what is the artist's intent.
There was a parlor aquarium fad in the 19th century, and while there are contemporary texts on aquaria, they have not been well-researched technically. The aquarium in the Winterthur collection consists of a splash pan, octagonal tank, and a central architectural structure. It is constructed primarily of painted tinned iron, galvanized iron, and glass. While the octagonal tank shape was common, there are no comparables for this object as a whole. The technical examination of this aquarium aimed to more thoroughly characterize and understand the materials and construction, with the goals of adding to the body of knowledge on 19th-century aquaria, investigating whether this object was intended to actually hold water, and possibly providing information on whether the pieces are original to one another. Techniques used in the analysis of this aquarium include: examination in ultraviolet light, x-ray fluorescence (XRF), cross-section microscopy, scanning electron microscopy – energy dispersive spectroscopy (SEM-EDS), Fourier Transform infrared spectroscopy (FTIR), gas chromatography mass spectrometry (GCMS), Raman spectroscopy, and x-ray diffraction (XRD). Analysis identified compositional differences in the glass panes in the tank that correspond to visual differences, mercury-tin mirrors, bronze powder paint and a zinc white and barium sulfate containing oil paint. The tank sealant was found to contain a drying oil and a lead component, and a coating on the lower part of the architectural structure seems to contain a drying oil. Akageneite was identified in the iron corrosion on the tank. These findings inform treatment and display of the object, as well as indicating that the aquarium likely did not hold water in its current configuration.
The Dennis Farm, located in northeastern Pennsylvania’s Susquehanna County, is possibly the oldest African-American-owned farm property in the nation still retained by the original family’s descendants. The Dennis Farm Charitable Land Trust (DFCLT) was formed in 2001 to preserve this rare historical resource. A collection of layered wallpaper fragments from the house was brought to Winterthur Museum to help provide information on the materials and manufacture. With at least seven layers of wallpaper from just the dining room, there is a wealth of information to be analyzed within those redecorating campaigns. The scope of this project focused on analyzing the oldest wallpaper from the dining room using XRF, Raman and FTIR spectroscopies, and polarized light microscopy (PLM), and only PLM for fiber identification of the rest of the papers, which will be analyzed further at a later date. Prussian blue, synthetic ultramarine, barium sulfate, and gum Arabic were identified in the blue pigment sample of the oldest wallpaper, and gypsum and calcium carbonate were identified in the white pigment sample. It was found that animal glue was most likely used to hang this oldest paper layer, and that the paper is composed of primarily bast fibers.
Cathode ray tube (CRT) monitors have played an important role in the development of contemporary culture. As such, they have made their way into the collections of museums and other institutions concerned with cultural heritage. They exist in these collections straddling the lines between display equipment, artwork, and objects, but in most cases their functionality is of crucial importance to the role they play. The unique aesthetic of a CRT display has become emblematic of a particular moment in the history and yet, a CRT's ability to product its display in inherently finite. CRTs are in large part considered as consumables that have a brief finite operational lifespan. Thus, consideration of the material lifespan of any single monitor seems to have rarely been considered. As time moves on CRT stockpiles are drying up. Replacement is becoming increasingly difficult and conservation treatments are being devised that aim to preserve the original aesthetic of a given CRT monitor even after its internal electronics have failed. The central question at the core of these conservation efforts is whether one must choose to prioritize a CRT monitor's existence as an object or as functional equipment. In an effort to help develop a more comprehensive approach toward dealing with this question an analytical investigation of the material constituents of components present within a 1985 QuasarTM CRT monitor was undertaken. Using techniques including FTIR, XRF, SEM-EDS, and Py-GC/MS for the characterization of materials present in the monitor's chassis, printed circuit board (PCB) substrate, and various internal electrical components, found brominated flame retardants, acrylonitrile butadiene styrene (ABS), and unsaturated polyester resin. These findings not only lead to a more in-depth understanding of the vulnerabilities of individual component materials, but also to recognition of the material interactions at work as well as the operating conditions inherent to functionality of the electrical system.
This report presents information on the materials characterization of magnetic - or self-adhesive - photograph album leaves, and the potential deterioration pathways of these materials and photographs. Introduced sometime in the mid-20th century, these peel-and-stick leaves are double-sided, laminated structures composed of adhesive-coated paperboards and transparent, plastic cover sheets. There have been no scientific studies published on magnetic photograph albums to date. The goal of this study was to identify the paperboards, adhesives, and plastic cover sheets that are in contact with photographs in three historic albums. In addition, the deterioration of the individual materials and composite structures were investigated. The technical examination of the album leaf materials included a combination of invasive and noninvasive analytical techniques including ultraviolet-induced visible fluorescence photography, x-ray fluorescence, polarized light microscopy, Fourier-transform infrared microspectroscopy, and pyrolysis-gas chromatography/mass spectrometry. Results showed that the album leaves were composed of laminated, bleached hardwood paperboards, rubber-based adhesives, and isotactic polypropylene or plasticized poly(vinyl chloride) cover sheets. Possible deterioration pathways of the albums were proposed.
With the advent of rapid prototyped materials and recent advances in the technology, artists, architects, and designers can now conceive of and produce complex artworks relatively instantly. This explosion of rapid prototyping affects museum professionals as they are seeing a significant number of art and design objects produced by these processes entering their collections without full knowledge of their aging properties. One such object is Gemini, a chair designed by Neri Oxman in (b. 1976) that was acquired by SFMOMA in 2015. Gemini is constructed through both additive and subtractive manufacturing. The curved cherry wood chassis was fabricated in Brooklyn, NY by SITU Fabrication using a CNC milling method, while the polymeric nodules were printed in Israel by Stratasys using an Objet500 Connex 3 Polyjet printer. The printed components combine three different polymers, Vero Magenta, Vero Yellow, and Tango+, in 44 different combinations to achieve variations in color, opacity, and rigidity. Polymers used in rapid prototyped materials are typically proprietary, giving only general information about the ratio of ingredients. Without a complete understanding of the material components conservators are not able to predict accurately the expected material lifespan of an object. By conducting analysis to understand the material components of Polyjet polymers used in Gemini, we can better understand the material additives and degradation, and investigate if the printing method has any effect on the degradation of the material. Techniques used in the technical analysis of Gemini included Fourier-transform infrared spectroscopy (FTIR), scanning-electron microscopy/energy dispersive spectroscopy (SEM-EDS) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), evolved gas analysis GC/MS, and x-ray fluorescence (XRF).
Little is known about the history of this privately owned carriage model. This technical examination aims to define the materials used in the production of the object in order to aid in understanding this object’s place in history. The art historical research done by the author suggests that the carriage is in the style of an 18th-century vehicle, but the materials and construction do not support this date range for the model’s manufacture. The materials were analyzed using a variety of spectroscopic and chromatographic techniques. Among the materials discovered were drying oil paint binders, commonly used mineral pigments, as well as galvanized iron sheet metal. The analyses provided materials information supporting the art historical interpretation that the model dates to the 19th century.
Edward Steichen (1879-1973) was an American painter and photographer who worked predominately in the United States and France. The focus of this paper is to identify materials and techniques used by Steichen in Rose-Geranium (1910) and Petunia-Begonia-The Freer Bronze (1913), one of the earliest and one of the latest murals painted for his In Exaltation of Flowers series. Visual observations and a multi-analytical approach were performed with ED-XRF, PLM, FTIR, GC-MS, and SEM-EDS analyses. This technical examination revealed the presence of lead white in the commercially primed Lucien Lefebvre-Foinet canvases, and Steichen's use of gilding and modern artist oil paints (some of the probable pigments include zinc white, cadmium yellow/orange, light cobalt violet, viridian, chrome green, cerulean blue, and a red lake). Later in his career, Steichen destroyed many of his painted works; and so, these murals show an obscure facet of the artist's oeuvre.
Books and albums are often greater whole than the sum of their parts. While the significance of an album is often in its cohesion, its analysis and study are most unified when taken piece by piece. The components of a souvenir photograph album from the Grand Tour era have been studied with various analytical techniques in order to characterize materials on its covers and endsheets. The upper cover of this album features a micromosaic inset. While micromosaics are traditionally made of enamel, its dull appearance is suggestive of plastics. Lead enamels colored with arsenic pigments were identified in the micromosaic decoration through non-destructive analysis. Cotton and wood fiber with lead, chalk, and barium fillers were detected through non-destructive analysis, and analysis of samples. In studying the component parts of a photograph album and its greater historical context, we were able to invalidate the presence of plastics.
A bough pot from the 19th century is the only one of its kind in the collection of the Winterthur Museum, Garden, & Library to be composed primarily of cellulose-based materials. Traditionally, bough pots are semi-circular shaped ceramics made to hold fresh cut flowers. The Winterthur bough pot presented the opportunity to study an example composed of unconventional materials, a watercolor drawing on paper adhered to the face of a semi-circular wooden structure finished with gold trim and gilded feet. The subject matter and style is an example of schoolgirl art intersecting with the decorative arts. The results of this technical analysis revealed a variety of papers and pigments, suggesting past campaigns were carried out for the care or restoration of this object. Through X-ray Fluorescence Spectrometry (XRF) and Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDS), a feasible palette was established: vermilion, lead red, Prussian blue, chromium oxide green (viridian), copper-based green (verdigris), green earth, Van Dyke brown, and umber. Possible pigments added at a later time include chromium oxide green (viridian), Prussian green or Prussian blue with chrome yellow, lead white, as well as blanc fixe and titanium white. Gas Chromatography Mass Spectrometry (GC-MS) confirmed the presence of pine resin and dammar resin in the coatings; a substantial peak for hydroxyproline indicates the use of an animal-based adhesive from a mammalian source and may be a contributing factor in the overall deterioration of the watercolor. The result of this study dates the production of the bough pot to the late 1830s or later, which is outside of the 1780–1820 timeline of when schoolgirl art was most popular. Yet, the stylistic expression and substantial use of pine resin suggests possible attribution to this genre.
A garden landscape painted in 1973 by Fay Peck (1931-2016) was examined as part of the first known technical study of the artist's painting materials. An interview with the artist and her two daughters was conducted to gain insight into the material choices and working techniques employed. Microscopy and instrumental analysis were used to understand the materials and their deterioration with the goal of developing an appropriate treatment plan. Techniques employed included XRF, PLM, FTIR, Raman, SEM-EDS, and Py-GC-MS. A combination of analysis and knowledge gained from the interview revealed the layering structure of the artwork as a wax-tempered Masonite panel with an acrylic ground and thickly applied paint. The artist used a modern palette composed of both inorganic and synthetic organic pigments bound in drying oil(s); all colors analyzed included the filler barium sulphate and possibly other modifying agents such as wax and metal stearates. A combination of cross-sectional microscopy and Py-GC-MS discovered the presence of a degraded coating possibly composed of pine resin and aldehyde resin.
Ritual musical instruments from Tibet have not been well-researched in a technical context. Through a wide range of analytical techniques, this study focused on a Tibetan drum (damaru) from the University of Pennsylvania Museum of Archaeology and Anthropology in an effort to understand material processing such as leather tanning, tassel making, and dyeing that is specific to the region of Tibet. X-ray fluorescence spectroscopy (XRF), Fourier-Transform Infrared Spectroscopy (FTIR), Raman spectroscopy, Fiber-Optics Reflectance Spectroscopy (FORS), Micro-chemical spot testing, transmitted and polarized light microscopy, and High Pressure Liquid Chromatography - Mass Spectrometry (HPLC-MS) were used to characterize original materials including the beadwork, leather, and dyed textiles. The analysis identified lead glass beads, coral beads, oil- or brain-tanned leather, natural dye sources from Amur cork tree and madder species, and a synthetic triarylmethane dye (Basic Violet 14). The data and technical details gained from this object contribute to the database of Tibetan and Asian materials.
Buddha's Descent from Tavatimsa (ACP 1645/WAM 35.263) in the collection of the Walters Art Museum is the subject of a technical study at the Winterthur/University of Delaware Program in Art Conservation. It is dated 1850-1900 and painted in a water-soluble medium on wood panel, likely teak. Although English-language technical research on Thai painting has mostly been focused on wall paintings, manuscript illuminations, and banner paintings on cloth, to the author's knowledge no studies have been completed on paintings on panel supports. Polarized light microscopy (PLM), cross-section microscopy with fluorochrome staining, x-ray fluorescence spectroscopy (XRF), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), x-ray powder diffraction spectroscopy (XRD), and gas chromatography-mass spectrometry (GC-MS) were all used to study the materials and techniques of the Walters's panel. Pigments and fillers likely identified in the panel include zinc white, calcite, synthetic ultramarine, vermilion, red lakes, carbon black, barium sulfate, emerald green, iron oxides, and lead white. The ground was identified as primarily calcium carbonate with barium sulfide, wurtzite (ZnS), and monimolite (Pb3(SbO4))2 impurities. The pigments identified are consistent with late 19th-century Thai painting practice. Binder analysis in GC-MS yielded a distribution of sugars suggesting the binder is a gum, although further research is needed to determine the source. The metal leaf on the panel is gold, while the metal leaf on the frame appears to be a gold alloy. PR 49:1 (lithol red) was also identified as the red paint on the frame, suggesting it was made in the 20th century. It is hoped this will add to the body of knowledge on Thai painting in English-speaking countries.
An embroidered silk broadside, dated 1823, and its associated frame in the collection of Winterthur Museum underwent technical analysis to provide a clearer understanding of its manufacture, to contribute to the body of knowledge pertaining to press-printed and textile-based ephemera, and to answer specific questions presented by the object. Analysis sought to gain more information about the dyes of the embroidery threads, to identify the materials of the frame, and to characterize the adhesives used on the silk during previous mounting campaigns. Examination under ultraviolet illumination determined the characteristic fluorescence of dyestuffs and residues on the verso of the textile, and x-ray fluorescence spectroscopy (XRF) was used to survey the elemental composition of the components of the silk and embroidery. Results of high-performance liquid chromatography-photodiode array-mass spectrometry (HPLC-PDA-MS) suggested the presence of safflower and possibly turmeric in the pink embroidery threads, a yellow grass in the yellow embroidery threads, and possibly a lichen dye for the purple embroidery threads. The frame was also examined with XRF, and cross-section samples were analyzed with scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS);the results of instrumental analysis were compared with scholarly sources pertaining to gilt surfaces. Analytical findings suggested that the frame was created several decades after the broadside. Fourier transform infrared (FTIR) spectroscopy confirmed an acrylic based pressure sensitive adhesive from a likely recent remounting, and gas chromatography-mass spectrometry (GC-MS) identified the presence of a synthetic-rubber based adhesive residue on the silk from an older mounting campaign.
Weathered by centuries-long natural degradation and multiple restoration campaigns, a panel painting of the Madonna and Child was brought to the Winterthur/University of Delaware Program in Art Conservation in October 2015 for conservation treatment and technical analysis. The work had been tentatively dated to 1520s-1530s and attributed to Perino del Vaga, although its history and provenance prior to the 1880s was, and remains, unknown. Since a thorough understanding of the painting's original and restoration materials can aid in dating, attribution, and conservation treatment choices, the painting underwent extensive instrumental analysis. Initial examination was conducted with ultraviolet illumination, X-radiography, and infrared reflectography (IRR) to image the coatings, carbon-based underdrawing, presence and distribution of restoration materials, and general construction of the painting. Sample analysis with a combination of polarized-light microscopy (PLM), X-ray fluorescence spectroscopy (XRF), fiber-optic reflectance spectroscopy (FORS), scanning-electron microscopy with energy-dispersive X-ray (SEM-EDS) and backscattered-electron (BSE) detection, and Fourier-transform infrared spectroscopy (FTIR) confirmed the use of the pigments lead white, carbon black, vermilion, red lake, verdigris, iron oxides, and smalt; optical microscopy and SEM-EDS were crucial in understanding the composition and stratigraphy of the painted layers, while gas chromatography-mass spectrometry (GC-MS) aided in the identification of the drying oil medium. X-ray diffraction (XRD) analysis confirmed the presence of a traditional gypsum ground. These scientific results suggest that the painting's materials and technology are consistent with those used in central Italy after 1520; however, the analysis was not conclusive with regard to the attribution to Perino del Vaga. Further art historical research targeted at the provenance and stylistic characteristics of the painting may offer more precise dating and attribution.
This study focuses on analyzing and characterizing the remaining surface coatings and consolidation materials found on a large-scale wooden eagle in the collection of the Winterthur Museum, Library &Gardens. The goal was to gain a better understanding of the object's history and any undocumented treatments, and chemically verify known treatments in its history as both a garden feature and indoor object of folk art. A combination of qualitative x-ray fluorescence (XRF), optical microscopy (OM) in both visible and ultraviolet light, scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS), and Raman spectroscopy was used to characterize the polychrome finish. Fourier transform infrared spectroscopy (FTIR) and gas chromatography coupled to mass spectrometry (GC-MS) were used to characterize the binding media and further identify the repair and consolidation materials on the sculpture. Most of the surface of the sculpture is a mix of weathered bare wood, and an alligatored, reddish brown coating. It was believed to have been partially, or fully stripped, and refinished prior to entering the Museum collection. This study revealed multiple paint campaigns in the alligatored areas, including a likely first coat of chrome yellow paint, and evidence of gilding in one sample.
Black- and red-figure ceramics are widely recognized and studied; yet the technology and processes of their manufacture remains unknown. It is through the investigation of materials of these ceramics, including this fragmented black-figure ceramic olpe (42.48) from the collection of the Johns Hopkins Archaeological Museum, that a better understanding of the techniques used in the construction and firing can be understood. In poor condition, this ceramic (42.48) had failing restoration material also analyzed for identification purposes, ultimately informing the treatment methodology used in the object's treatment. Investigative techniques used in the study of the olpe include X-Ray Fluorescence (XRF), Scanning Electron Microscopy- Energy Dispersive Spectroscopy (SEM-EDS), Fourier-Transform Infrared Spectroscopy (FT-IR), Raman Spectroscopy, and X-Ray Diffraction (XRD), as well as x-radiography and visual examination under regular and ultraviolet illumination. Analysis identified the elemental and molecular composition and stratigraphy of the earthenware ceramic, as well as the restoration materials present including animal glue, polyvinyl acetate adhesive, and an inorganic silicate coating.
Automata No. 1 (2005) is a contemporary sculpture by the artist Keith Tyson (b. 1969); it was gifted to Winterthur/University of Delaware Program in Art Conservation after it was damaged and declared a total loss. Automata No. 1 was fabricated by Prototype New York, a leading fabricator based inNew York, for the exhibition Geno Pheno 2 held at Pace Gallery in 2005. Since no known technical analysis has been carried out on works by Keith Tyson, contact was first made with Pace Gallery and Prototype New York in an effort to gain information on the materials and manufacture of this piece. Techniques used in the technical analysis of Automata No. 1 included x-ray fluorescence (XRF), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, scanning-electron microscopy/energy dispersive spectroscopy (SEM-EDS) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Technical analysis aided in understanding the information provided by the gallery and fabricator, vulnerabilities associated with the proprietary materials used and the inherent issues associated with those materials. Finally, insight gained from technical analysis informs thoughtful conservation treatment protocol for Automata No. 1 and contributes to the knowledge of modern materials used in the fabrication of contemporary art.
This paper examines the painting materials and techniques of William Williams, Sr.'s (1727-1791) Self-Portrait in the Winterthur Museum collection. As Williams's latest-known work, his self-portrait displays greater naturalism and advancements in painting technique that distinguish it from the known body of Williams's oeuvre. This, in addition to several compositional changes revealed through x-radiography, have prompted scholars to ask when and where this portrait was painted, and why it differs so greatly in style and technique from Williams's other attributed works. In addition to close visual analysis of paint application and technique, this technical study characterized and identified the materials used by Williams through the use of the following instrumentation and optical microscopy techniques: x-ray fluorescence spectroscopy (XRF), cross-sectional microscopy, scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), polarized light microscopy (PLM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and x-ray powder diffraction (XRD). The organic and inorganic materials lead white, chalk (with the presence of intact coccoliths), yellow earth, red earth, vermillion, bone black, soot black, Prussian blue, Van Dyke brown, and a red lake pigment were identified. The data gathered is compared to past technical analysis of paintings attributed to Williams. Furthermore, this technical study presents the possibility that Williams's style and painting technique were later influenced by the practices of London painters, and explores the artistic exchanges between British and American artists at the end of the eighteenth century.
A painting by Susan Macdowell Eakins was examined in order to determine the pigment choices of the artist. In addition, two palettes believed to have belonged to Thomas Eakins were examined and compared with historical accounts and previous technical studies. Examination techniques included UV examination, IRR, x-radiography, and cross-sectional microscopy. Analytical techniques used in this study included PLM, XRF, SEM-EDS, and Raman. Possible pigments detected included zinc white, cobalt blue, chrome yellow, vermilion, and iron earths in the painting, lead white, cobalt blue, vermilion, and iron earths in the Bryn Mawr palette, and ultramarine, lead white, iron earths, and vermilion in the Hirshhorn palette. Further molecular analysis is required to identify these pigments more definitively. The results of these studies were compared to determine whether there were any distinct differences between Macdowell and Eakins's materials. Finally, the results of this comparison were used to determine whether there could be an underpainting executed by Eakins underneath Macdowell's work.
The ability of painted enamels on copper to imitate porcelain led to the popularity of the medium in the 18th century and the production of utilitarian items such as candlesticks, decanter labels, and quadrille dishes. European production of painted enamels was most prevalent in England, with large workshops located in Battersea, South Staffordshire, Bilston, Wolverhampton, and Birmingham. The production of painted enamels was a technology that greatly interested Emperor Kangxi of China, who imported western specialists and soon after established an imperial painted enamel workshop. Previous research of European and Chinese enamels indicates the regions used similar production methods and materials. This study examines a 18th-century quadrille dish to determine if the materials present are consistent with English enamels or if they are indicative of a Chinese export origin. Analytical techniques including binocular stereomicrosopy, ultraviolet (UV) illumination, XRF, FTIR, SEM-EDS/BSE, and Raman spectroscopy were used to characterize the composition of the dish. The enamel is inferred to be comprised of a silicate network with tin oxide opacifier and potash flux. The colorants were found to be primarily iron oxides, cobalt, colloidal gold, and Pb-Sn-Sb oxide. All materials detected are consistent with materials used on both English and Chinese 18th-century enamels.
Extant examples of early American portraiture are fraught with anonymous artists, unknown sitters, and unclear provenances. Historic Odessa's Boy with a Fowler is attributed to William Williams, but there were up to four artists of the same name with work circulating the colonies during the mid-late-18th century. Using X-ray Fluorescence, SEM-EDS, FTIR, Raman Spectroscopy, Polarized Light Microscopy, cross-sectional analysis, FORS, and colorimetry – a better understanding about the composition, working method, and subsequent treatment is gained. These results are compared with the results of the same analytical protocol used on known examples of William Williams's (1727–1791) work from the Winterthur Museum and Brooklyn Museum of Art. The results from Boy with a Fowler, in combination with results from known William Williams's works, can provide useful data for future study of attributed paintings.
In the summer of 2015, a sheet-brass skimmer (a common kitchen tool used to skim foam from broth or cream from milk) was brought to the Winterthur objects lab for coating removal and polishing, but it was discovered that the shiny brass object was in fact not coated. The shininess of the skimmer was a puzzle for conservators who believed that without a coating the piece should have been heavily tarnished. While originally attributed to William Kirby, a New York City pewterer who was active during the last quarter of the 18th century, the skimmer also displays some odd physical characteristics that do not correspond with more traditional known examples in the Winterthur collection. It was hypothesized that the skimmer was possibly a 20th-century copy or replica of early brass skimmers. A skimmer with more typical characteristics and patina was chosen to serve as a comparison to the questioned skimmer. Partnered with connoisseurship study of skimmers in American and England, analytical techniques were chosen to illuminate differences between the two skimmers to gain information about their date of manufacture and any compositional differences. In addition to information about elemental composition obtained with x-ray fluorescence spectroscopy (XRF), corrosion products and residues sampled from each skimmer were examined using optical microscopy, Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy. XRF revealed no major differences between the two alloys, and Raman spectroscopy was unsuccessful in identifying any of the corrosion products. While most corrosion products were similarly unidentified with FTIR, a polish residue was positively identified, supporting the idea that the questioned skimmer was polished since its arrival at Winterthur without proper documentation. Partnered with the study of these brass skimmers is the analysis of two copper alloy candlesticks coated during the 1980s with cellulose nitrate-based lacquers. While this part of the study is in its early stages, FTIR has been conducted to confirm the identity of the coatings. These candlesticks will be further analyzed to understand how cellulose nitrate interacts with brass surfaces to contribute to a larger study of brass objects and their treatment at Winterthur.
At present, Asian lacquer has been widely studied but its complex materials and manufacture processes are not well understood. An in-depth technical study of a lacquer sewing table at the Winterthur Museum, Garden, and Library, corroborates recent findings in Chinese export lacquer research and adds to the growing body of literature in the area of less thoroughly characterized component materials. The object at the center of the study exhibits the layer structure associated with export furniture manufacture techniques, including a wooden substrate, double ground with proteinaceous binder and intermediate fiber layer, two lacquer layers, red "bole," and metallic powder decoration. Cross-section microscopy, utilizing visible and ultraviolet light, x-ray fluorescence spectroscopy (XRF), Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), and scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) were all employed in material characterization and identification of organic and inorganic components. The study identified unanticipated beta cristobalite and aragonite in the ground layers in addition to quartz, kaolinite, calcite, and magnetite, characterized two gold powders, one of which contains silver, and identified mercury in the red “bole” layer. Additionally, two natural resin restoration coatings were characterized utilizing FTIR, as was a copper- and zinc-containing restoration overpaint. Further proposed research aims to identify the species of lacquer used and likely organic additives using pyrolysis-gas chromatography/mass spectroscopy.
Technical analysis of ceramic objects can inform both provenance and possibilities for treatment. This study focuses on a prime example of early 19th-century Liverpool wares, an oversized creamware jug from the Winterthur Museum collection. Characterization of original materials and problematic additions from a restoration campaign are pursued through elemental, molecular, and phase identification. The composition of the ceramic body is characterized qualitatively using X-ray fluorescence spectroscopy (XRF), scanning electron microscopy-energy dispersive spectrometry (SEM-EDS), and x-ray diffraction (XRD). Enamel colorants are characterized using XRD, SEM-EDS, and Raman spectroscopy. Restoration materials and organic components are assessed for stability and reversibility with Fourier transmission infrared spectroscopy (FTIR) and Raman spectroscopy, as well as ultraviolet light examination. This study presents analytical results that are consistent with historical accounts of methods in Liverpool's Herculaneum Factory. A lead-glaze and metal oxide colorants in the enamels were identified, as well as insoluble epoxy resins in the joins.
To date, a limited number of technical studies of Chinese export lacquer objects have been published. While the literature often focuses on Asian lacquer made for the domestic market, Chinese lacquer produced for the export market has a significant presence in collections all over the world, and the materials used to construct these objects play an important role in their instability and need for conservation treatment. A combination of energy dispersive X-ray fluorescence (ED-XRF) spectroscopy, scanning electron microscopy with energy dispersive x-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and X-ray diffraction (XRD) was used to characterize and identify materials present in a Chinese export lacquer tray within the Winterthur Museum collection (c. 1775-1800). Vermillion and mixtures of gold powers were identified in the decorative surface. These materials – as well as the kaolinite, calcite, quartz, dickite, and a proteinaceous binding media in the ground – were found to be consistent with literature results. Although the presence of lacquer was confirmed by FTIR, Py-GC/MS will be undertaken in the future in order to better characterize the species of lacquer and lacquer additives present in this object.
An 1877 watercolor drawing by architects Collins & Autenrieth showing the design for a frescoed ceiling in the Central Presbyterian Church in Philadelphia was examined using in-situ and sample-based analytical techniques. Analysis was carried out in an effort to characterize the materials used in its creation as well as to identify the dark degradation product seen on areas of lead white so as to determine appropriate treatment protocols. The unusually late use of lead white, as well as the use of body color raised questions concerning the Philadelphia-based German firm's working methods. XRF, FTIR, and Raman spectroscopy were used to identify Vermilion and Prussian blue, both common pigments used in American architectural drawing of the 19th century. Although gum Arabic was identified through FTIR as a binder, rabbit skin glue was also identified, showing that distemper was used on the drawing to some extent. This practice correlates to contemporary interior decoration, especially that done by German immigrants. The dark degradation products of lead white could not be positively identified.
Connie Fox's Cézanne is a contemporary sculpture created in the 1960s using a variety of modern materials. These include paint, two different plastic films, two different adhesive tapes, metal, rigid plastic, paper, and graphite. Photographs, a magazine clipping, drawings, and paint were all utilized to create imagery on the six faces of the cube. The focus of this technical study was the material characterization of the cube components. The sealed interior of the cube creates a microclimate, and it is important to know what materials are present, as some will off-gas pollutants as they deteriorate which may degrade surrounding materials. Using ED-XRF and FTIR, the paint was characterized as titanium white and a cobalt-containing blue pigments in an acrylic binder. The screws were identified as various iron alloys. Fillers in one of the plastic films were identified. The two adhesives in the pressure-sensitive tapes could not be identified at this time. Further material characterization will take place as items are accessible; at this time only certain components in the cube can be accessed for sampling.
Harper Trenholm Phillips (1928-1988) was an African American artist and teacher whose work ranged from figural to abstract paintings and assemblages. His work is in many collections throughout the United States but his materials and working methods have not been studied. This article presents the results of an investigation of the materials he used in Cross-Between, an undated, unsigned assemblage now the Paul R. Jones collection at the University of Delaware Museum. By reconstructing aspects of Phillips's artistic process, it is hoped that this study might be a first step in establishing a chronology of his progression as an artist. Such investigation can also be useful for providing clues for authenticating or dating his other works. The complementary analytical techniques used in this study were: energy dispersive x-ray fluorescence (ED-XRF), Fourier transform infrared spectroscopy (FTIR), scanning electron microspectroscopy with energy dispersive x-ray spectroscopy (SEM/EDS), and Raman microscopy. Visual and technical analysis aids in diagnosing the physical condition of an artwork and for establishing appropriate conservation treatments. The investigation provides a basis for further study of Phillips's work and other African American artists who remain under-represented in American museum collections and hence in the art historical and conservation literature. Technical analysis confirmed the presence of a variety of synthetic adhesives, resins, pigments, and binders. The artist's non-homogeneous layered surfaces necessitated the use of several complementary analytical techniques to identify the mixtures of materials present.
In the fall of 1999, the Germantown Crier reported on a painting which had been found in fine arts storage of the Germantown Historical Society (GHS). This "mysterious portrait" lacked any documentation except for an old photograph that indicated the painting was in the possession of GHS since the 1940s. The Crier revealed a story of 17th-century New Orleans intrigue where Bourbon Spain and the young American Republic met in the hands of a Yucatec emigré, José Francisco de Salazar y Mendoza. Since the portrait was attributed to Salazar at the end of the 20th century, scholarly interest on the artist and his contemporaries has grown. This study aims to contribute to the scholarship on Salazar, the first known painter in New Orleans, through technical analysis of the materials used to execute the Germantown portrait. Through analytical methods such as energy dispersive x-ray fluorescence (XRF), scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS), Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR) and gas chromatography mass spectrometry (GC-MS), pigments, binders, and other materials were identified as characteristic of a Colonial Spanish painter. X-ray radiography, ultraviolet imaging, infrared-reflectography, polarized light microscopy, and fluorochrome staining were also used as complementary techniques to further identify materials and process. While this study does not lead to an absolute attribution, it ultimately functions as a starting point that other paintings by Salazar may be compared against, as no other comprehensive studies on the artist's methods and materials have been completed to date.
Of all his paintings of ethereal angels and allegorical figures, Abbott Handerson Thayer considered his Winged Figure of 1904 (Freer Gallery of Art, Washington D.C.) to be one of his “real contributions to humanity.” In this monumental painting of the artist’s youngest daughter, dressed as an angel, Thayer included an applied wreath of gilded laurel leaves around the girl’s head—a unique element in his oeuvre that he never repeated. Upon recent examination of the Freer’s Winged Figure in the summer 2014, many questions were raised about the painting’s condition and original materials. The present technical study, carried out by the author in collaboration with the Winterthur Museum’s Scientific Research and Analytical Lab (SRAL), was initiated to gain a better understanding of Thayer’s working methods, to elucidate the unknown materials comprising the wreath, and to gather data on the pigments, binding media, and fillers in the paint. Techniques used for this investigation included: examination with the aid of magnification under normal light and ultraviolet light, energy dispersive x-ray fluorescence spectroscopy (XRF), cross-sectional microscopy, polarized light microscopy (PLM), scanning electron microscopy with energy dispersive x-ray spectroscopy (SEM-EDS), SEM in the backscattered electron mode (SEM-BSE), Fourier-transform infrared spectroscopy (FTIR), gas chromatography-mass spectrometry (GC-MS), Raman spectroscopy, and X-ray diffraction (XRD).
Japanese swords have always been of interest in western cultures. They are classified according to the period in which they were made and the length of the blade. This work analyzes the materials with which a short sword (ko-wakizashi) was made. X-ray fluorescence spectroscopy and UV light were used as preliminary non-destructive tests. The blade and knife are made mostly with an iron alloy, while the knife’s hilt and the habaki are made mostly of copper. The decorations have a lead base and are painted with gold and other pigments such as malachite and cobalt blue. FTIR was employed to characterize the adhesive observed where the kashira should be, and it was determined to be Nikawa. Two samples were taken from the lacquer and they were observed under optical and electronic microscope. Both ground layers seem identical and have silicon as their base, suggesting that layer was made with jinoko, a diatomaceous clay.
This technical analysis seeks to provide information regarding the unique painting techniques of Honoré Daumier (1808-1879) and the materials that he used. The Prison Choir, an oil painting on canvas of an unknown date, belonging to the Walters Art Museum, is analyzed through the use of XRF (x-ray fluorescence), cross-section microscopy and fluorochrome staining, SEM-EDS (scanning electron microscopy with energy dispersive spectroscopy), FTIR (Fourier transform infrared spectroscopy), and Raman spectroscopy to determine what materials may have been used, what of the present composition is likely original, and what may have caused the currently deteriorated state of the painting. Pigments found in the painting include: lead white, Prussian blue, calcium sulfate hemihydrate, hematite, carbon black, bone black, and emerald green. The presence of carbohydrates was suggested in the varnish layer, through fluorochrome staining. Oxidized linseed oil was identified through FTIR and the presence of drying oils was confirmed through GC-MS in addition to the presence of pine resin and mastic varnish. While the study was informative, the analysis did not provide information that will, at present, aid in treatment decisions or change the current interpretation of the artists' working style or oeuvre. At this stage of the research, bone black can be added to the list of pigments used by Daumier and also the presence of emerald green on a painting on canvas.
A polychrome sculpture of a Virgin of the Immaculate Conception from Quito, Ecuador of unknown origin and date was examined using multiple analytical techniques and instruments in an effort to determine date, understand the materials used in its construction, and the materials used in previous restorations to assess the treatment to be carried out. X-radiography provided information on the construction of the sculpture which was made from three vertical planks of wood adhered together, likely held together with an adhesive and/or wooden dowels. X-radiography also revealed the extent of the degradation of the wooden support from past insect infestations, losses in the ground and paint layers, and the possible use of a radio opaque filler (such as lead white) from past restorations. Cross-section microscopy revealed the presence of four generations of paint layers, including a layer of gilding in the first and second generation, indicative of the use of the estofadopolychromy technique. UV fluorescence and fluorochrome staining suggest the use of a carbohydrate and protein binder in the first three generations of paint and an oil binder for the fourth generation. XRF confirmed the use of vermillion for the areas of red in the flesh and the underside of the blue mantle, possibly lithopone in the yellow of the neck of the dress, and lead white for the white dress. SEM-EDS corroborated the use of gypsum for the ground layer, an iron-rich layer underneath the gilding, (most likely a bole), gold for the gilding in the first generation, and silver for the gilding in the second generation, indicative of the use of the estofado a la chinesca technique. FTIR revealed the use of cellulose nitrate as a consolidant in areas of loss on the face. Raman spectroscopy confirmed the use of Prussian blue as the color used for the latest blue layer on the mantle, and indigo blue in the original paint layer of the mantle. Initially believed to be a 19th-century sculpture, is now thought to have been made at an earlier date, possibly the 17th century.
The technical analysis of a leaded glass scent bottle with pomander finial and its shark skin covered case with an unclear attribution was undertaken to aid in determining the composition of the residues within the scent bottle, determining whether the tarnish was intentional or natural, and attributing the objects to a known culture and time period. X-ray fluorescence (XRF), FORS-UV-VIS, scanning electron microscopy- energy dispersive x-radiography (SEM-EDS), Raman spectroscopy, and Fourier transform infrared spectroscopy (FTIR) were conducted on the objects to aid in the clarification of the questions surrounding the pieces. XRF determined that the bottle was composed of leaded glass rather than rock crystal and that the tarnish was sulfur based. FORS-UV-VIS revealed that the dye used on the velvet was likely not indigo based. SEM-EDS confirmed that the fibers in the velvet were composed of cotton. FTIR revealed that the contents of the scent bottle were likely a mixture of cellulosic and protein-based materials. Raman Spectroscopy identified the silver tarnish as silver sulfide.
This technical study examines the materials and methods used to construct two late 18th-century birth and baptismal certificates, or Taufscheine in German, from the collection of the Winterthur Museum, Garden, and Library. A combination of microscopic and spectroscopic analytical instrumentation was used to gain insight into the manufacture of this object and contextualize it within the tradition of other Taufscheine from this period and location. Techniques employed in the study of this object included examination under ultraviolet radiation, fiber microscopy, x-ray fluorescence (XRF), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy. The results of this technical analysis determined that the palette of the two Taufscheine is not completely consistent with analysis conducted on similar fraktur. The colorants consistent with previous analysis are gamboge, red lead, vermilion, and Prussian blue. The red lead and vermilion, though, were found to be mixed with a significant amount of iron oxide, not typically found in fraktur. The green colorant was determined to be atacamite, and to date there are no reports on atacamite as a colorant in fraktur.
Over the past 40 years, Pennsylvania German illuminated paper objects, or fraktur, have been studied by art historians, art conservators, and conservation scientists. A typical palette of colors and materials is known, but more research is needed as collections of fraktur continue to grow, and conservation issues for the objects arise. The colorants, binders, and paper support used to produce a Pennsylvania German cutwork valentine, or fraktur, an object in the Winterthur Museum’s collection were analyzed using polarized light microscopy (PLM), ultraviolet (UV) illumination, X–ray fluorescence spectroscopy (XRF), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy. The materials identified were consistent with typical fraktur materials and helped to inform the object’s conservation treatment.
A modern painting entitled Variations on White (1969) by second-generation Abstract Expressionist Robert Goodnough (1917–2010) was recently gifted to the Winterthur/University of Delaware Program in Art Conservation, as it was deemed untreatable due to heavy staining of the canvas itself as well as a prominent brown spatter stain on much of the left half of the canvas. Thus far, there is one study published on the ageing of Goodnough's sized canvases, but there are no published technical analyses of Goodnough's paintings to date. Technical analysis has been conducted to help understand Goodnough's unique working method as well as the degradation of the painting, in order to aid in scholarship of the artist and his works and to inform testing and possible treatment of the painting. A combination of x-ray fluorescence (XRF), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, x-ray diffraction (XRD), and scanning-electron microscopy/energy-dispersive spectroscopy (SEM-EDS) identified the pigments lead white, zinc oxide, titanium dioxide (rutile form), chrome yellow, and cadmium red, as well as the fillers calcium carbonate, calcium sulfate anhydrite, and barium sulfate. Polarized light microscopy (PLM) identified the pigments hematite and earth yellow and also determined the presence of black pigment particles, the identification of which could not be ascertained with PLM or instrumental analysis. FTIR identified the binder as an alkyd, and gas chromatography/mass spectrometry (GC/MS) confirmed the presence of this alkyd binder. Cross-section analysis and staining demonstrated that Goodnough painted in a layered system with acrylic on the bottom and an oil-containing (oil or alkyd) layer on top. GC/MS of the unstained size material detected polyethylene glycol (PEG), an acrylic surfactant, and GC/MS of a brown spatter stain material detected erythritol, phosphate, arsenic and tartaric acid, which together indicate that the stain may be from wine.
The study of New Spanish painting poses a series of difficulties related with the existence of a large body of anonymous or decontextualized images, lack of historical documentation, and the conservation condition in which these images are studied stylistically. This study focuses on a decontextualized Mexican painting depicting the Virgin of Guadalupe surrounded by four corner scenes that illustrate the story of Her apparition. Upon preliminary examination it was noted that the primary support of the painting had a vertical seam. The differing thread counts of the two canvases and the presence of dark blue paint on the back of the seam allowance led to the conclusion that the support was constructed from two older paintings. Art historical research on devotional copies of the Virgin of Guadalupe provided evidence that seams were considered necessary for the creation of “true" copies. The analytical techniques used in this study include: energy dispersive x-ray fluorescence (XRF), scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and in the backscattered electron mode (BSE), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), and gas-chromatography mass spectrometry (GC-MS). Other examination techniques include: ultraviolet light examination, infrared reflectography, X-radiography, polarized light microscopy (PLM), and cross-sectional microscopy with fluorochrome staining. Infrared reflectography revealed the presence of two similar overlying painting campaigns depicting the Virgin and the apparition scenes. Cross-section microscopy corroborated the presence of two paint generations over the re-used painted supports. The materials discovered on each campaign parallels the methods found in historical art manuals and in recent technical studies of Mexican colonial paintings dating from the 17th to the 19th centuries. Prussian blue and indigo were found on the canvas at the right suggesting this re-used painting was created in the in the late colonial period after 1704. Ultimately, the presence of Prussian blue provided a terminus post quem for the execution of the painting.
Pennsylvania German objects are rarely the subjects of scientific analytical examination, despite being sources of great insight into the technologies and materials available to that culture. In this study, two copies of a book referred to as the Martyrs’ Mirror, printed and supposedly bound at the Ephrata Cloister in Pennsylvania in 1748, underwent multiple analytical examinations to attempt to confirm the origins of the bindings and characterize the materials used to produce them. These large books are the results of the largest printed edition in Colonial American history, and their bindings are comprised of a variety of materials. The metal, pigments, paper, ink, and leather components in the bindings were characterized and identified where possible in an attempt to confirm that the books could have been completely fabricated at one location in rural Colonial Pennsylvania.
Javanese shadow puppet theater, or wayang kulit, is considered to be the highest form of art in Indonesia. However, there has been little research into the materials and techniques used to create these highly decorated puppets. A Javanese shadow puppet owned by Bob and Mae Carter was analyzed using polarized light microscopy, x-ray fluorescence (XRF), Fourier-transform infrared spectroscopy (FTIR), and Raman spectroscopy. Through analysis, an acrylic binder was identified in the paint layers. In addition, lithopone, chrome yellow, and Prussian blue were identified as pigments in the painted areas. The gilded areas of the crown were identified as being a bronze powder suspended in an organic binder. This technical analysis contributed to the overall knowledge of materials used to decorate Javanese shadow puppets and will inform future treatment of the object.
Life-size painted wooden figures known as dummy boards or silent companions are certainly mystical as their original purpose remains speculative. A recent conservation treatment of a dummy board figure in Turkish costume provided the opportunity to investigate an example of these objects from a material perspective. PLM, cross-section analysis, XRF, SEM-EDX, and Raman were employed to explore the decorative palette, detecting evidence of Prussian blue, vermillion, lead white, and various earth pigments. X-radiography and XRF were primarily used to unpack restoration campaigns relying especially on barium and chromium as anachronistic markers. Results confirm an 18th-century palette of fine artist quality suggesting that visual appeal was more prominent than practical function for contemporary owners of these companions. Cross sections, FTIR, and GC-MS results show that the subsequent coatings applied to the surface of this dummy board were a mixture of local and cheap materials including drying oil, pine resin, and mineral wax. These ingredients are slightly more consistent with recipes for polishing common furniture, highlighting a shifting value in this type of object from the 18th to the 20th century. Composition of the ground and preparatory layers visualized with SEM suggest an outdated practice, which could be linked to a Dutch cultural origin of these figures.
Photographic postcards were popular during the late 19th and early 20th century. During this time, the demand for color photography resulted in the application of colorants to photographic images as an attempt to represent life as it is in nature. This technique of coloring or applying media was also utilized on the photographic postcard. The results were often conveyed in colors unrealistic to the natural world and included the use of metallic salt toners, organic dyes, and synthetic pigments. This report is an investigation into the characterization and identification of these materials in order to confirm that they are characteristic with late 19th- and early 20th-century photographic finishing materials. An additional goal of this investigation was to confirm the image material and presence of a baryta layer. X-ray fluorescence spectroscopy (XRF) as used to confirm the image material as silver, the presence of barium and sulfur - which are indicative of the baryta layer -- and the presence of materials known for dye toning and dye tinting (inorganic components such as uranium, copper, potassium, and iron). Raman spectroscopy was used to characterize organic dyes on two of the postcards (GACP 1541e and GACP 1541h), with inconclusive results.
The materials composing an early 18th-century blue-and-white transfer-printed English earthenware plate with related repairs will be investigated and characterized through several different analytical techniques. During the late 17th and early 18th centuries many English potteries began producing wares imitating Chinese porcelain in a cost-effective manner to meet the needs of a growing middle-class market. Blue-and-white transfer-printed wares evolved from this mass-production of clay forms and decoration techniques. Since ceramics are a hard, brittle material and prone to breakage, many materials and techniques have been and are utilized for their repair. While technical studies focused on English transfer-printed wares of the late 18th early 19th centuries are next to non-existent, there are many studies involving the investigation of ceramic materials including Florentine ceramic glazes (Zucchiatti et al. 2006), terracotta figures from Cyprus (Aloupi et al. 2000), English steatitic porcelains (Jay and Orwa 2012), and English Staffordshire enamels (Fair and Mass 2013). Investigative techniques utilized in this study include visual examination under normal and UV light, x-radiography, XRF, SEM-EDS, FT-IR, Raman Spectroscopy, and GC-MS analyses. Results reveal a fine earthenware body of alumino-silicate matrix primarily with a potassium flux, lead glaze with cobalt oxide colorant in both the underglaze blue and transfer-print, poly(ethyl cyanoacrylate) adhesive and losses filled with an epoxy resin bulked with clay minerals overpainted with acrylic emulsion paints titanium white, Prussian blue, and a third light blue overpaint, which is unidentified.
A 19th-century diary from the Winterthur Library contains watercolor botanical illustrations of plants native to the Northeastern United States. A technical analysis of the diary focused on colorants used in two illustrations and design media from a marbled paper covering the boards. X-ray fluorescence (XRF), Fourier-transform infrared (FTIR), Raman spectroscopy, and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), were used to characterize design media, and adhesives. Pigments for the marbled paper are tentatively characterized as: (yellow) raw umber; (red) red lead and an anhydrous iron (III) oxide; (blue) indigo, Prussian blue, a basic copper carbonate (i.e. azurite), and atacamite or paratacamite; (pink) an organic dye precipitated to a chalk base. The palette for the botanical illustrations is tentatively characterized as: (yellow) gamboge, and possibly a lake yellow; (blue) Prussian blue; (green) a green mixed from yellow and blue colorants; (brown) an earth, likely sienna or burnt umber; (red) an anhydrous iron (III) oxide, and a red lake; (purple) a purple mixed from blue and red colorants. FTIR analysis of an adhesive for a collaged element within the diary was a close match to gum Arabic, the binder for watercolors paints. This possible use of gum Arabic as an adhesive suggests the artist may have prepared her own paints, rather than working from a commercial kit.
Materials analysis of a soft paste porcelain mug (accession # 56-13-1) in Winterthur's collection was performed to verify the originality of the handle and to characterize the various materials used in both the manufacture and repair of the mug during subsequent treatment campaigns. The object, manufactured by Lowestoft and dated to 1789, was purchased by Winterthur in 1956. As there has been no analysis on Lowestoft porcelain in Winterthur's collection to date, the study facilitated a better understanding of this mug as well as other Lowestoft pieces in the collection. Analysis was performed using the following techniques: x-ray fluorescence spectroscopy (XRF), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), gas chromatography-mass spectrometry (GC-MS), Raman, and Polarized Light Microscopy (PLM). This study assessed the materials and methods of manufacture of the mug as well as began an investigation into the object's repair history and found the following. The mug is a bone ash soft-paste porcelain with lead glaze and cobalt colorants as literature on Lowestoft Porcelain suggests. The fill is composed of plaster, mastic, shellac, oil, and beeswax, and visibly shows more than one campaign of repair. The handle is a replacement and was likely attached twice during the mug's history.
Two sauceboats excavated from the National Constitution Center site within Independence National Historical Park are believed to be the products of Bonnin and Morris--America's first successful porcelain manufactory--based on stylistic similarities and prior XRD analysis of the clay body. However, long-term anaerobic conditions have caused the lead glaze to darken, obscuring the potential maker's mark on the underside of the base as well as much of the other blue underglaze decoration. Instrumental analysis using XRF, SEM-EDS, Raman, and FTIR techniques in conjunction with experimental analysis were performed: 1) to contribute to knowledge about the material parameters of Bonnin and Morris wares by comparing both sauceboats to Winterthur's own fruit basket, 2) to investigate the sulfides believed to be responsible for the darkening, and thereby 3) to elucidate the mechanisms involved, and, in turn, 4) to inform future treatment methods. Results from XRF and SEM-EDS show that the sauceboats are similar to each other, as well as the fruit basket, in terms of elemental composition: a calcium, potassium, silica, and titanium in the clay body with cobalt and nickel in the underglaze decoration and a lead glaze; there are also high amounts of iron present throughout. However, experimental results showed that burial conditions have caused rust-red iron staining underneath the lead glaze that has darkened to lead sulfides; on top, copper and zinc staining have caused irregular black staining as well, as seen with FTIR.
Edward S. Curtis's seminal text and photographs, The North American Indian, has been influential in the history of depictions of Native Americans and important to the understanding of photogravure as an art form. Photogravure plates were used to reproduce his photographs for the publication of books as well as large portfolios of images. Through X-ray fluorescence spectroscopy (XRF), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, and gas chromatography-mass spectrometry (GC-MS), the plates and their coatings were analyzed. Through these analyses, information about the deterioration products and mechanisms for deterioration was gathered to provide insights into the future preservation efforts of similar materials asl well as information about the past use of these images. The plates are copper that has been steel-faced; analysis of the coatings indicates a mixture of beeswax, paraffin wax, and an asphalt. Analysis of corrosion on the plates using Raman spectroscopy has identified the corrosion as containing α-iron (III) oxide.
A heavily deteriorated painted leader head from a Philadelphia residence, dated to 1792, was examined to better understand the materials used in its construction, coating history, and assess its state of preservation for proposed treatments. X-ray fluorescence confirmed the substrate composition to be made from relatively pure copper and the cast ornaments as lead. The solder was characterized as a leaded-tin alloy. Examination using SEM-EDS confirmed the presence of lead and copper throughout the coating layers, iron in the red, zinc in the earliest white layers, and chromium and barium found at the most recent green paint layer. FTIR confirmed the presence of basic copper sulfate (antlerite), a common corrosion product found on copper surfaces exposed to polluted urban environments. Cross-section microscopy revealed deterioration phenomena of dendritic green-stained resin penetrating into the white agglomerates, which could not be characterized with elemental analysis or fluorochrome staining. Microscopy also revealed a grey ground followed by either gilding or a blue paint layer which was characterized as Prussian blue using FTIR.
This technical study examines the materials and methods used to construct a 19th-century Pennsylvania German illuminated paper wall pocket from the collection of the Winterthur Museum, Garden, & Library. A combination of microscopy and analytical instrumentation were used to gain insight into the manufacture of this object and contextualize it within the tradition of other Pennsylvania German decorative art forms of this period. Techniques employed in the study of this object included polarized light microscopy (PLM); cross-sectional microscopy with a fluorescent histological staining protocol; examination under ultraviolet radiation; x-ray fluorescence spectroscopy (XRF); Fourier transform infrared spectroscopy (FT-IR); Raman spectroscopy; and gas chromatography-mass spectrometry (GC-MS). The results of this technical analysis confirmed the palette of the Winterthur paper wall pocket—vermilion, indigo, chrome yellow, and possibly lead red and degraded verdigris—is consistent with its attributed 19th-century date and previous XRF analysis. Several materials not previously studied were positively identified or characterized through Raman and FT-IR spectroscopy including the blue colorant indigo, a proteinaceous adhesive, and carbohydrate-based coating.
Pith paper paintings were a popular item in the Chinese export trade to the West in the 19th century. These beautiful images were made using watercolors or gouache on the pith of Tetrapanax papyriferus, creating a rich paint layer on a translucent support. This study examined the image border material and pigments of an album from the Winterthur Museum using X-ray Fluorescence spectroscopy (XRF), Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), and ultraviolet light microscopy. Vermilion, red lead, gamboge, lazurite, azurite, Prussian blue, and lead white were identified as the palette materials, although there remains to be full identification of the green, brown, and black colorants. The paint binder tested positive for proteins and is probably an animal-based glue. The silk borders were adhered with a starch-based adhesive.