(302) 831-4863 werrell@udel.edu

Jennifer Mass received her PhD in inorganic chemistry from Cornell University and did a Mellon postdoctoral fellowship at the Metropolitan Museum of Art.  She has conducted the scientific study of works of art in museum and academic contexts for over twenty years fifteen of these at the Winterthur Museum, Garden, and Library. She has also taught instrumental analysis of objects of art in U.S. master’s degree programs in art conservation for her entire career.  She is currently a Consulting Senior Scientist at the Rijksmuseum and affiliated faculty in the University of Delaware Art Conservation Department and the Department of Chemistry and Biochemistry. She formed Scientific Analysis of Fine Art, LLC (SAFA) in 2007 because of the growing need for the objective material assessment of objects in the art market that complements the expertise of the connoisseur and conservation assessments.  Her work at SAFA allows her to assist art collectors, dealers, auction houses, and private conservation firms in addressing questions of authenticity, state of preservation, and provenance of works ranging from the Dutch Golden Age to the works of the early modernists and expressionists, Meissen, Sevres, and Chinese Export porcelain, as well as continental, English, and American silver.  She also has a broad expertise in folk and vernacular art, including Pennsylvania German painted furniture, fraktur, New England painted furniture and weathervanes.

Jennifer’s research interests include the degradation mechanisms of artists’ pigments and developing nondestructive depth profiling methods for imaging buried paintings. Recent projects have included examining the photo-degradation of cadmium yellow in works by Matisse and imaging a portrait buried beneath an early Picasso interior scene (The Blue Room, 1901, the Phillips Collection). Jennifer has published numerous articles on her research in the art conservation and scientific literature, including Studies in Conservation and Applied Physics A. She has co-edited three volumes – two volumes of Materials Issues in Art and Archaeology, and Handheld XRF for Art and Archaeology. Jennifer gives dozens of lectures a year on her work nationally and internationally, and has received awards for her research from the Italian Society for Nondestructive Testing and from the American Materials Research Society.   Jennifer’s work has received worldwide media attention, being highlighted on NPR’s Science Friday and MSNBC as well as in The New York TimesThe Washington Post, the BBC, the L.A. Times, London’s Daily Telegraph and numerous other national and international media outlets.

Abstract for Materials Characterization  Workshop at UD:

Synchrotrons, Semiconductors, and The Scream:
Pigment Degradation Mechanisms of the Early Modernists
Uncovered with New X-Ray-Based Methodologies

Cadmium sulfide (CdS) is a bright yellow semiconductor that has numerous important commercial applications in solar cells, as a phosphor, a piezoelectric, and a solid state laser.  In recent years it has received particular attention for the creation of solar cells with tin oxide/cadmium sulfide/cadmium telluride-based device structures. The highest efficiency for these cells is achieved by exposing this structure to cadmium chloride during the annealing process.  However, the long-term stability and performance of these systems may be adversely affected by the introduction of chlorides. This data has come to us not through artificial aging studies of solar cells, but, surprisingly, through studying the paintings of the Impressionist and post-Impressionist masters.

Cadmium sulfide is not a modern material, having been used extensively as an artists’ pigment since the 1840s. It has recently been the subject of intensive research in the art conservation community because its light-induced degradation is currently compromising billions of dollars of paintings by the Impressionist and early modernist masters.  This degradation of cadmium-based yellow pigments is occurring in works by Edvard Munch and his contemporaries, including works by van Gogh, Picasso, Matisse, and Seurat. The discoloration of cadmium yellow paints in works from the 1880s through the 1920s has been ascribed to the photo-oxidative degradation of the main component of these pigments, cadmium sulphide, and residual chloride in this pigment is correlated with the acceleration of the photo-degradation. This degradation can lead to profoundly disfiguring changes in the painting, including fading, darkening, and flaking of the paint depending upon which degradation pathway is followed. The different appearances of the degraded regions is due to the large variety of photo-oxidation products that can be formed, including cadmium oxides (which are dark brown), cadmium sulphates (which are white), and cadmium carbonates (also white). The cadmium yellow pigments on Edvard Munch’s iconic painting The Scream (1910, the Munch Museum) have altered to a grey colour, and are mixtures of cadmium sulfide and cadmium carbonate.  Cadmium carbonate is not thought to be a photo-oxidation product in this painting, but rather a residual starting reagent from the production of the pigment.  The role of cadmium carbonate in the 1910 version of The Scream will be discussed, as well as how the work has changed over time, and why the 1893 version of The Scream is in excellent condition.

Evidence for the degradation of the yellow paints in Henri Matisse’s Le Bonheur de vivre (1905-6, The Barnes Foundation) has been observed since the 1990s. In contrast to The Scream c. 1910, changes in this iconic work of Matisse’s Fauvist period include lightening, darkening, and flaking of the yellow paints. The reasons behind the changes occurring in the work will be discussed, including the faded region below the central reclining figures and the darkened foliage in the upper left quadrant of the painting. These regions are visible below (see lower left), compared to an unaltered final oil sketch of the painting from the Museum of Modern Art, San Francisco.

Investigation of the degraded yellow paints in this work involved non-destructive molecular analysis techniques including X-Ray Absorption Near Edge Spectroscopy (XANES) and Scanning Electron Microscopy-Energy Dispersive X-Ray Analysis (SEM-EDS), Fourier Transform Infrared (FTIR), and Raman Microscopy. To determine if different chemistries could be observed for the faded versus darkened regions of the paintings, Synchrotron Radiation-micro Fourier Transform InfraRed (SR-µFTIR) Spectroscopy, X-Ray Fluorescence (SR-µXRF) mapping, and micro X-Ray Absorption Near Edge Spectroscopy (µXANES), and full field XANES imaging of milligram-sized paint samples were conducted. The positions of the cadmium-containing phases identified (such as cadmium sulfate, cadmium carbonate, and cadmium chloride) were used to help discern the role of these materials as synthesis starting reagents, paint fillers, or photodegradation products.