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Scientific Analysis

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  • Sampling adhesive residue from tape on a contemporary plastic sculpture 


Scientific Research and Analysis Laboratory

Master’s-level students complete their second-year science coursework in the 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.

These courses enable our students to gain hands-on experience in data collection, interpretation, and evaluation for a range of instrumental techniques, including Raman spectroscopy, x-ray fluorescence (XRF), Fourier-transform infrared spectroscopy (FT-IR), gas chromatography - mass spectrometry (GC-MS), x-ray diffraction (XRD), liquid chromatography-mass spectrometry (LC-MS), pyrolysis GC-MS, and scanning electron microscopy with x-ray microanalysis (SEM-EDS). 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. Students prepare assigned lab reports focused on the practical application of instrumental methods in the analysis of works of art. A year-long technical study project 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 technical study projects have contributed new scholarship to the understanding of unusual cultural materials and treatment procedures. The ultimate goal of our second-year science curriculum is to produce conservators who will work as informed collaborators with scientists.

Dr. Jocelyn Alcantara-Garcia, Catherine Matsen and Dr. Chris Petersen provide student supervision and instruction in the Scientific Research and Analysis Laboratory.

Previous Technical Studies

2016 Abstracts​​

2015 Abstracts

2014 Abstracts

2016 Abstracts

Albertson, Gerrit. Using Thomas Eakins' Palettes as Reference Materials: Examination of a Painting by Susan Macdowell Eakins

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 in 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.

Bearden, Maggie. Study of an 18th Century Quadrille Dish – Chinese Export or English?

The ability of painted enamels on copper to imitate porcelain lead 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.

Beller, Alexa. Technical study of "Portrait of a Boy" – Attributed to William Williams

Extant examples of early American portraiture are fraught with anonymous artists, unknown sitters, and unclear provenances. Historic Odessa's Portrait of a Boy is attributed to William Williams, but there are 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' (1727 – 1791) work from the Winterthur Museum and Brooklyn Museum of Art. The results from Portrait of a Boy, in combination with results from known William Williams' works, can provide useful data for future study of attributed paintings.

Bright, Leah. A Comparison of Two Copper-Alloy Skimmers, Partnered with a Preliminary Investigation into Cellulose-Nitrate Coatings on Brass Objects

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.

Chasen, Jessica Burkhart. Technical Examination of a Chinese Lacquer Sewing Table

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.

Commander, Julia. Technical Study of a Creamware Jug from the Winterthur Museum Collection

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.

Corona, Madeline. Technical Study of a Chinese Export Lacquer Tray (1959.2891)

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.

Duncan, Emilie. Technical Analysis of a 19th-Century Architectural Drawing with Lead White Darkening

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.

Owens, Samantha. A Technical Study of a 1960's Composite Sculpture

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 are 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 im n the pressure-sensitive tapes were unable to 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.

Smith, Shelley M. The Materials Characterization of an Abstract Assemblage by Harper T. Phillips (1928-1988), Cross-Between from the Paul R. Jones Collection, University of Delaware Museum

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 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 Trenholm'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.

Summer, Josh. Technical Study of Unknown Portrait attributed to Jose Francisco de Salazar y Mendoza

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 C. 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 complimentary 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.

2015 Abstracts

Beall, Sydney. Abbot H. Thayer’s Gilded Age Winged Figure with Collaged Wreath

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).

Di Giacomo, Mariana. Analysis of the Materials Employed in the Elaboration of a Japanese Short Sword (ko-wakizashi)

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.

Dunn, Miranda. Analysis of Honoré Daumier’s The Prison Choir from The Walters Art Museum

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.

Garcia, Bianca. Technical Examination of an Ecuadorian Polychrome Sculpture

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 estofado polychromy 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. 

Gottschlich, Lauren. Follow Your Nose: An Investigation of a Scent Bottle and Case

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. 

Gupta, Anisha. A Tale of Two Sisters: The Material Analysis of a Pair of Pennsylvania German Fraktur

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. 

Johnson, Jacinta. Technical Study of a Pennsylvania German Cutwork Valentine

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 are known, but more research is needed as collections of fraktur continue to grow, and conservation issues in 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.

Johnson, Pamela. Diamonds in the Rough: Technical Analysis of Variations on White (1969), by Robert Goodnough

A modern painting entitled Variations on White (1969) by second-generation Abstract Expressionist Robert Goodnough (1917 – 2010) was recently given to the Winterthur/University of Delaware Program in Art Conservation as a gift, 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.

Lazarte, Jose. Revealing layers of meaning: Issues in the Construction and Iconography Found in a Painting depicting the Virgin of Guadalupe

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 historic 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 different thread count of the two canvasess 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 historic art manuals and in recent technical studies of Mexican colonial paintings dating from the 17th to the 19th centuries.  Prussian blue and indigo was 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 quemfor the execution of the painting. 

Magee, Cathie. Reflections of the Ephrata Cloister in the Martyrs' Mirror

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,1 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. 

Nichols, Alexandra. Hiding in the Shadows: Technical Analysis of a Javanese Shadow Puppet

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 .

Wroczynski, Emily. Silent No More: The Material Analysis of an American Dummy Board

Life-size painted wooden figures known as dummy boards or silent companions are certainly mystical as their original purpose remains speculation. 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, crosssection 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.

2014 Abstracts

Brogdon-Grantham, Shannon. The Technical Analysis of Ten Early 20th Century Photographic Postcards

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 accurately 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 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, the presence of materials known for dye toning and dye tinting  (inorganic components such as uranium, copper, potassium, and iron). Raman spectroscopy was done to characterize organic dyes on two of the postcards (GACP 1541e and GACP 1541h), with inconclusive results.

Brown, Emily. Technical Study of English Earthenware Plate

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.

Curran, Claire. The Technical Analysis of a Lowestoft Soft-Paste Porcelain Mug

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.

McCauley, Kelly. Technical and Experimental Analysis of Two Sauceboats with Darkened Glazes

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.

Namde, Ronel. Technical Examination of Photogravure Printing Plates from Edward Curtis' The North American Indian

Edward S. Curtis' seminal text and photographs, The North American Indian, has been infuential in the history of depictions of Native Americans and important to the 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 fuorescence 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 and information about their past use. The plates are copper that has been steel-faced and the coatings analyzed indicate a mixture of beeswax and paraffn wax and an asphalt. Analysis of corrosion on the plates using Raman spectroscopy has identifed the corrosion as containing α-iron (III) oxide.

Pedemonti, Nick. Examination of a Painted Copper Leader Head

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.

Curley, Austin Plann. Diary and Book of Watercolor Paintings: A Technical Study

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.

Sullivan, Michelle. Technical Study of a Pennsylvania German Paper Wall Pocket

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.​

Taira, Kimi. Technical Study of Two Chinese Export Pith Paper Paintings

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.

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  • The Department of Art Conservation
  • 303 Old College
  • University of Delaware
  • Newark, DE 19716, USA
  • Phone: 302-831-3489