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17
Chronicles in Wax-Resin Lining: A
Historic Look at Lining Practices and
Their Effectual Legacy on Paintings in
the Smithsonian American Art Museum
Collection
17. Chronicles in Wax-Resin Lining
Amber Kerr, Head of Conservation and Senior Paintings Conservator, Smithsonian
American Art Museum, Washington, DC
Gwen Manthey, Paintings Conservator, Smithsonian American Art Museum, Washington,
DC
Keara Teeter, Postgraduate Fellow, Smithsonian American Art Museum, Washington, DC
Kristin DeGhetaldi, Paintings Conservator, Independent Researcher
Brian Baade, Paintings Conservator and Associate Professor, University of Delaware
W. Christian Petersen, Volunteer Conservation Scientist and Affiliated Associate Professor,
Winterthur Museum, Garden & Library, Winterthur, Delaware
Catherine Matsen, Scientist and Affiliated Associate Professor, Winterthur Museum, Garden
& Library, Winterthur, Delaware
Paintings conservators at the Smithsonian American Art Museum ◆            ◆            ◆
survey conservation records to gather the historical recipes, treatment
protocols, and materials used over the past fifty years to build a INTRODUCTION
reference database connected to specific works in the collection. From
this information, the authors show how the database is being used to The Smithsonian American Art Museum (SAAM) in
re-create both historical wax-resin recipes and application techniques Washington, DC, together with its branch museum, the
through lining mock-ups. This material reference set is being used for Renwick Gallery, stewards a national collection containing
analytical and physical testing to learn more about the materials used
and how they degrade, and what influences mechanical as well as thousands of paintings that span more than three
environmental conditions have on both the lining recipes and centuries of American art. Established in 1829, the
reconstructions as they age. collection at SAAM moved to its current location in the Old
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Patent Office Building in 1968. This was just two years after were considered the best for loan based on the very fact
paintings conservator Charles Olin formed the first that they were wax-resin lined, and therefore considered
conservation lab for the collection. The paintings in the stable and nearly impervious to environmental fluctuations
collection have been cared for by four generations of or mechanical stresses.
conservators over the past fifty years.
The conservation records reflect evolving approaches to COLLECTION SURVEY AND LINING
the methodology and protocols used in the structural
treatment of paintings, as they encapsulate the training, RECONSTRUCTIONS
experience, and philosophical approaches to treatments A survey of the Lunder Conservation Center treatment
brought by each paintings conservator. Research into records was initiated to identify lined paintings in the
these past treatments continues in order to gain a greater museum collection. As of April 2019, this survey yielded a
understanding of the materials used as well as the preliminary data set of 958 linings carried out at the
application methods and overall intent of the treatments. museum from the 1950s to present. The data set was then
The initial phase of research focused on wax-resin linings filtered to exclude paintings mounted to solid supports,
and their effectiveness and longevity as a treatment option adhesives irrelevant to this study (glue paste and
for paintings in the collection, and, through the use of synthetic), and wax-resin adhesives where the materials
instrumental analysis, compared specific recipes recorded were unidentified. The final data set yielded fifty oil-on-
in treatments with samples from the paintings exhibiting canvas paintings lined between 1950 and 1993. The
lining deterioration. paintings were by thirty-seven different artists and on a
The impetus for the focus on wax-resin linings began variety of fabric supports (linen, cotton, and burlap). All
several years ago, when a significant number of those were wax-resin lined but nearly a dozen different recipes
lining treatments completed in the mid- to late twentieth had been used. The linings were added to address a
century were beginning to fail or showed early signs of variety of condition issues, including tears, generalized
failure. Modes of failure included but were not limited to flaking, or as a preventive measure (no condition issues
pocketed delamination of the lining substrate, returned noted).
cupping and flaking within the paint and ground layers, Six recipes were frequently used in the twentieth-century
and raised craquelure in the painted surface. Of note was lining treatments and were found in forty-three of the fifty
the delamination of linings related to works that were on surveyed paintings (table 17.1). These six recipes were
prolonged view in the galleries or had traveled on loan. then selected for comparative and categorical reasoning in
The latter was of particular concern, as these paintings order to answer the following queries:
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Table 17.1
The six case study paintings and their historical lining recipes (SAAM 1–6)
Case study painting 2019 re-created recipe Collection survey
Sun Setting, Denmark SAAM 1 (Keck recipe): SAAM 1 represents:
William H. Johnson, ca. 1930, oil on burlap 6 parts unbleached beeswax 1/50 lining recipes
Lined to linen (1969) 6 parts Multiwax W-445 1/6 Johnson paintings
Accession: 1967.59.720 2 parts dammar resin 1/10 linings to linen
2 parts colophony rosin
1 part gum elemi
Oak Trees SAAM 2: SAAM 2 represents:
Edward M. Bannister, 1876, oil on canvas 3 parts unbleached beeswax 29/50 lining recipes
Lined to fiberglass (1983) 3 parts Multiwax W-445 7/7 Bannister paintings
Accession: 1983.95.155 2 parts Zonarez B-85 14/18 linings to fiberglass
Cagnes-sur-Mer SAAM 3: SAAM 3 represents:
William H. Johnson, ca. 1928–29, oil on burlap 1 part unbleached beeswax 5/50 lining recipes
Lined to unidentified textile (1971) 1 part Multiwax W-445 5/6 Johnson paintings
Accession: 1967.59.702 1 part Piccolyte S-85 5/19 unidentified textiles
The Lesson SAAM 4: SAAM 4 represents:
Hugo Ballin, 1907, oil on canvas 3 parts Multiwax W-445 2/50 lining recipes
Lined to unidentified textile (1979) 1 part Zonarez B-85 1/1 Ballin paintings
Accession: 1910.9.1 1/19 unidentified textiles
Plenty SAAM 5: SAAM 5 represents:
Kenyon Cox, 1910, oil on canvas 3 parts Multiwax W-445 2/50 lining recipes
Lined to fiberglass (1974) 1 part Piccolyte S-85 1/2 Cox paintings
Accession: 1910.9.6 1/18 linings to fiberglass
The Windmill SAAM 6: SAAM 6 represents:
Jenne Magafan, ca. 1937, oil on canvas Multiwax W-445 4/50 lining recipes
Lined to unidentified textile (1979) 1/1 Magafan paintings
Accession: 1971.447.66 1/19 unidentified textiles
Note: Each case study painting represents a different historical lining recipe (SAAM 1–6). The third column compares each case study to surveyed lining adhesives,
prevalence of its use on other works by the same artist, and prevalence of its use with the same secondary support. The breakdown of secondary supports is as
follows: linen (10/50 linings), fiberglass (18/50 linings), combination of linen and fiberglass (3/50 linings), and unidentified textiles (19/50 linings). Supports for
Cagnes-sur-Mer, The Lesson, and The Windmill were unidentified in April 2019; visual examination later revealed that all three supports were linen.
Table: Amber Kerr, Gwen Manthey, Keara Teeter, Kristin DeGhetaldi, Brian Baade, W. Christian Petersen, and Catherine Matsen
Had other institutions also observed wax-resin lining The six recipes were each reconstructed to better
failure? This would be determined by examining a understand how the lining adhesives were aging and for
recipe frequently used by conservators working in a comparison against aged samples from known examples
range of institutions: SAAM 1. of use (the case studies listed in table 17.1).
Was the type of resin, type of wax, or their relative One case study was selected to represent each lining
proportions a source of failure? Two sets of recipes recipe, and samples of excess wax-resin adhesive were
would be compared to evaluate this question: SAAM 2 taken from each. The case studies represent a variety of
and 3 versus SAAM 4 and 5. painting techniques, as well as previous condition issues.
In the case of both William H. Johnson paintings, they had
Did the use, substitution, or absence of a particular been exposed to extremely poor environmental and
resin or an organic wax contribute to failure? This storage conditions prior to acquisition. In the case of The
would be determined using SAAM 6. Lesson by Hugo Ballin and Plenty by Kenyon Cox, those
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works entered the collection almost immediately after were masked in 10 cm (4 inch) wide strips with silicone-
their completion by the artists. In addition, the case studies release Mylar to prevent excess buildup of lining adhesive.
reflected differences in lining supports, and lining recipes
that are often repeated on other works by the same artist Once coated with the wax-resin mixture, each mock-up
(particularly in the works by Johnson and Bannister). painting was centered on its secondary support, placed on
the vacuum hot table, and sealed inside a silicone-release
Ingredients used in the recipes were sourced from various Mylar envelope. The vacuum suction pressure was set to 1
vendors, inventory at the Lunder Conservation Center, and Hg (0.49 psi) and the heat to 74°C (165°F). Emergency
donations coordinated with institutions and private thermal blankets were used to cover the Mylar envelope to
practice conservation studios. encourage even heat distribution. After fifteen to twenty
minutes of monitoring, the heat was turned off and the
The six reconstructed recipes were used in mock-up linings emergency thermal blankets removed. Then the mock-ups
of thirty-six test paintings. The test paintings consisted of were hand-pressed in a Union Jack pattern through the
commercial acrylic-primed cotton, acrylic-primed linen, Mylar envelope to push out excess wax-resin adhesive.
and oil-primed linen canvases mounted to 20 × 25.5 cm (8 Brayers were used over the thin and moderate paint
× 10 inch) wooden stretchers (twelve each). The authors layers, and cloth diapers were used over the thick impasto.
marked each canvas with graphite (underdrawing) and The lining procedures followed for the research project
applied Weber Permalba zinc and titanium white, Gamblin reflect treatment reports as well as oral history interviews
yellow ochre, or Old Holland red ochre oil paints; four of with former staff conservators.
each canvas type were painted out with each pigment
type. These pigments were chosen based on the practical
experience of the authors and conventional wisdom that SAMPLE PREP AND ANALYSIS
they dry quickly.
Scraped lining adhesive samples were collected from
Viscosity was divided into three categories: thin, moderate, eighteen of the fifty surveyed paintings (including all six
and thick oil paint. The thin layer was diluted in mineral case study paintings), raw wax and resin ingredients, and
spirits and applied lightly using 2.5 cm (1 inch) nylon flat each lining reconstruction adhesive. Technical examination
brushes so that the graphite underdrawing remained was carried out in May and June 2019 at the Winterthur
visible. The moderate layer was conservatively applied Museum’s Scientific Research and Analysis Laboratory
from the tube by brush (brushed gently to an even layer (SRAL).
with little brush marking), obscuring the underdrawing.
The thick layer was liberally applied from the tube by brush For the first stage of analysis, samples were prepared for
and palette knife to build up impasto. All mock-ups were Fourier transform infrared spectroscopy (FTIR). The
aged for four days at room temperature and then samples were flattened onto diamond cells to be analyzed
desiccated for fifteen days in a Lab-Line L-C oven set with a Thermo Scientific Nicolet 6700 FTIR spectrometer.
between 32°C and 40°C (90°F and 105°F). Once the oil paint The samples were spread out as a translucent film using a
was completely dry, each mock-up was photographed stainless steel microroller, and the diamond cell placed on
before treatment, removed from its stretcher, and lined to the platform of a Nicolet Continuμm Infrared Microscope.
38 × 43 cm (15 × 17 inch) fabric supports, distributed evenly One or two target sites were selected on the diamond cell,
between linen and fiberglass. and data were collected in transmission mode. Spectral
resolution was set at 4 c-1 for 128 scans (each scan ranged
Ingredients for each reconstructed lining recipe (see table from 4000 c-1 to 650 c-1). The resulting spectra were
17.1) were measured by weight and bundled in interpreted using OMNIC Series Software (version 8.0) and
cheesecloth in packages weighing 1 kg each. The six compared to the Infrared and Raman Users Group (IRUG)
cheesecloth packages were added to 24 × 24 × 9.5 cm (9.5 × spectral database.
9.5 × 3.75 inch) Gotham Steel nonstick fry pans and heated
on an iSiLER CHK-S1809NE portable induction cooktop to During the second stage of analysis, samples were
126°C–238°C (260°F–460°F). Large impurities were transferred to Thermo Fisher Scientific autosampler vials
separated out as the molten wax-resin components to be analyzed with an Agilent Technologies 7820 gas
permeated through the cheesecloth. Once filtration was chromatograph and Agilent 5975 Mass Selective Detector
complete, cooktop temperatures were reduced to 82°C (GC/MSD). The autosampler vials were treated with 1 part
(180°F). The molten mixture was transferred to the mock- Grace Alltech Meth-Prep II reagent in 2 parts benzene
ups (canvas reverse) and secondary support fabrics using (≤100 µL) and warmed in a Lab-Line Multi-Blok heater at
polyester paint rollers. The cotton/linen/fiberglass edges 60°C for an hour. The derivatized sample was pipetted into
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a vial insert and cooled to room temperature. From each raw material components, as that step would require a
vial, 1 μL of the sample was injected into the HP-5ms GC more discerning analytical technique.
column (5% phenyl methyl siloxane; flow rate of 1.5
mL/minute; film thickness of 30 μm × 250 μm × 0.25 μm).
After injection of the sample, Agilent G1701EA GC/MSD
ChemStation software was used with Winterthur
RTLMPREP method set to the following conditions:
Inlet temperature set at 320°C in “splitless mode” with
a nine-minute solvent delay
GC oven temperature set at 55°C for two minutes and
then ramped up 10°C per minute to 325°C, followed by
a ten-minute isothermal period
Transfer line temperature to the MSD in scan mode at Figure 17.1  FTIR spectra comparing Sun Setting, Denmark (top) and the re-
280°C, the source at 230°C, and the MS quad at 150°C. created recipe SAAM 1 (bottom). The painting was lined in 1969 with “waxadhesive (Keck)” to Belgian linen. SAAM 1 was prepared in 2019 following the
Keck recipe from the “Lab Formulas—Mixtures” binder (ca. 1967–74). Spectral
Chromatograms and mass spectra were interpreted using similarity between these results indicates the success in reconstructing this
Agilent MSD Enhanced ChemStation data analysis software historical wax-resin adhesive. Spectra: SRAL, Winterthur Museum, Winterthur,
with NIST MS Search v.2.0 database. Delaware / Composite image: SAAM, Washington, DC
During the final stage of analysis, samples were
derivatized with 3 μL tetramethylammonium hydroxide GC/MSD provided supplemental information about the
(TMAH; 25 wt.% in methanol) and placed in a stainless steel material composition of each adhesive mixture. Odd-
Eco-Cup (50 μL). The Eco-Cup was inserted into a Frontier numbered chain length hydrocarbons and certain fatty
Lab Multi-Shot EGA/PY-3030D for pyrolysis with a Hewlett acids (including palmitic, stearic, and lignoceric acids)
Packard 6890 gas chromatograph and HP 5973 mass identified beeswax in the sample. Odd- and even-
selective detector (Py-GC/MSD). The Eco-Cup was fitted numbered hydrocarbons with a reduced fatty acid content
with an Eco-Stick and inserted into the pyrolysis interface, indicated the presence of microcrystalline wax in the
where the sample was purged with helium using a single- unadulterated samples such as The Windmill and SAAM 6.
shot method at 600°C for twelve seconds. Separation was However, the presence of microcrystalline wax was more
achieved with an Agilent J&W DB-5ms 19091S-433 capillary difficult to detect in samples containing a mixture of
column (30 μm × 250 μm × 0.25 μm) with helium carrier ingredients. Multiwax W-445 was present in all twelve
gas set to 1.2 mL/minute. The split injector was set to samples; however, it was detected in only three case study
280°C with a split ratio of 30:1 and no solvent delay (9.26 paintings (The Lesson, Plenty, and The Windmill) and four re-
psi). The GC oven temperature program began at 43°C for created recipes (SAAM 2, and 4–6). In this data subset,
two minutes, ramped up by 10°C per minute to 325°C, and beeswax was absent from six of the seven samples.
then set a five-minute isothermal period (total run time =
34.7 minutes). The MSD transfer line was set at 320°C, the Some natural resins were successfully identified with
source at 230°C, and the MSD quad at 150°C. The mass GC/MSD: 5-dammarenolic acid methyl ester signaled the
spectrometer was scanned from 33 to 600 amu at a rate of presence of dammar, dehydroabietic acid and 7-oxo-
2.59 scans per second. Total run time was 29.4 minutes. dehydroabietic acid1 signaled colophony, and α- or β-
amyrin signaled gum elemi. The two proprietary resins
Zonarez B-85 and Piccolyte S-85 were not conclusively
RESULTS AND DISCUSSION detected with GC/MSD (fig. 17.2, table 17.2). This could be
the result of shortcomings in the sample derivatization
Each case study painting, SAAM reconstructed recipe, and process or sensitivity of the GC/MSD instrument. Other
raw material sample was analyzed using FTIR and GC/MSD. research publications have also cited discrepancies in
The goal of FTIR analysis was to compare the transmission identifying resins due to oxidation, depolymerization, or
band pattern of the historical linings to the reconstructed cross-linking of the material as it ages (Bleton and Tchapla
recipes (fig. 17.1). This comparison helped measure the 2009; Lluveras et al. 2010; Martín-Ramos et al. 2018;
efficacy of replicating SAAM’s historical lining recipes. FTIR Modugno and Ribechini 2009).
was not used to confirm the presence or absence of the
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Figure 17.2  Total ion chromatograms (TICs) for the Oak Trees lining recipe as
shown in GC/MSD (top) and Py-GC/MSD (bottom). Oak Trees was lined in 1983
with “1.5 p. Multiwax 445, 1.5 p. beeswax, 1 p. Zonarez B-85 resin” to
fiberglass. In GC/MSD, microcrystalline wax was not detected (lack of even-
numbered hydrocarbon peaks), and Zonarez B-85 was also not detected. In Py-
GC/MSD, peaks span from C8H8 to C35H72, indicating the presence of both
Multiwax 445 and beeswax; additionally, Zonarez B-85 was detected at 136
m/z, 272 m/z, and 408 m/z. Chromatograms: SRAL, Winterthur Museum,
Winterthur, Delaware / Composite image: SAAM, Washington, DC
Table 17.2
Wax and resin ingredients confirmed with GC/MSD to be present in the six case study paintings and re-created lining
recipes
Ingredient Compounds in waxes/resins detected with GC/MSD Retention time (min.) Ions (m/z)
Unbleached beeswax Odd-numbered hydrocarbons (peak at C27H56) 24–25 (peak) 71, 74
Fatty acids (most peak at C24H48O2)
Multiwax W-445 Odd- and even-numbered hydrocarbons (peak at C33H68 or C34H70) 28–29 71
Dammars 5-dammarenolic acid methyl ester (C31H52O3) 29–30 454
Colophony Dehydroabietic acid (C20H28O2) 21–24 316, 328
7-oxo-dehydroabietic acid (C20H26O3)
Gum elemi α-amyrin / β-amyrin (C30H50O) 29–30 426
Note: Each ingredient is identified by the presence of specific compounds at a particular molecular weight (m/z). GC/MSD seemed to have difficulty detecting
microcrystalline wax (particularly when beeswax was present in the recipe) as well as the proprietary resins Zonarez B-85 and Piccolyte S-85 (not listed in table).
Table: Amber Kerr, Gwen Manthey, Keara Teeter, Kristin DeGhetaldi, Brian Baade, W. Christian Petersen, and Catherine Matsen
For the final stage of this research, three historical linings polylimonene monomers, dimers, and trimers associated
and associated SAAM recipes were analyzed with Py- with the two proprietary resins (table 17.3; see fig. 17.2).
GC/MSD: Oak Trees and SAAM 2; The Lesson and SAAM 4; After reviewing the GC/MSD data in comparison with the
Plenty and SAAM 5. Raw samples of Zonarez B-85 and Py-GC/MSD data, the GC/MSD extracted ion
Piccolyte S-85 were also pyrolyzed as a control standard for chromatograms (EICs) were found to contain “humps”
data comparison. The results indicated that Py-GC/MSD along the baseline that matched the pattern for
was more successful in detecting the odd- and even- polylimonene (fig. 17.3). Other recipe ingredients—
numbered hydrocarbons present in microcrystalline wax. beeswax, dammar, colophony, and gum elemi—were also
This method was also more proficient in detecting the clearly identified with Py-GC/MSD.
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Table 17.3
Resin ingredients confirmed with Py-GC/MSD to be present in three of the case study paintings and three re-created
lining recipes
Ingredient Compounds in resins detected with Py-GC/MSD Retention time (min.) Ions (m/z)
Zonarez B-85 Limonene monomer (C10H16), dimer (C20H32), and trimer (C30H48) 3–10 136, 272, 408
Piccolyte S-85 Limonene monomer (C10H16), dimer (C20H32), and trimer (C30H48) 3–10 136, 272, 408
Note: Both Zonarez B-85 and Piccolyte S-85 were identified by the presence of the acid-catalyzed dimerization and trimerization of limonene.
Table: Amber Kerr, Gwen Manthey, Keara Teeter, Kristin DeGhetaldi, Brian Baade, W. Christian Petersen, and Catherine Matsen
possible lining mixtures may be characterized by sensorial
qualities to the examiner, particularly if they can be
compared against the reconstructions. This rough
characterization may allow for a generalized prediction of
a particular lining’s failure potential, when considered in
tandem with the exhibition history and previous condition
issues of the painting in question.
This study has provided an understanding of how
pervasive wax-resin linings are in the collection, and how
late the practice remained in use. The frequency of lining
treatments was likely prompted by extensive loan requests
and the contemporaneous belief that wax-resin linings
were a suitable preventative measure. While this analysis
has been useful, many initial questions remain
unanswered. We have a foundation with which to test
future hypotheses on how these materials deteriorate,
although the methods for testing these hypotheses must
still be designed. Since the reconstructions were lined,
areas of impasto have already been observed to contribute
to lining delamination in the unstretched lined mock-ups,
Figure 17.3  SAAM 5 extracted ion chromatograms (EICs) in GC/MSD (top) and raising new questions about environment, tension, and
Py-GC/MSD (bottom). Limonene in Piccolyte S-85 is detected as a monomer at
136 m/z, dimer at 272 m/z, and trimer at 408 m/z. GC/MSD barely detected the percussive movement.
compound, as indicated by the jagged appearance of the baseline in all three
EICs. Py-GC/MSD yielded better results, with clearly defined peaks for the It is the hope of the authors that these mock-ups and this
compound. Chromatograms: SRAL, Winterthur Museum, Winterthur, Delaware preliminary study will provide a resource and reference for
/ Composite image: SAAM, Washington, DC future fellows and researchers to enrich our collective
understanding of the aging and failure mechanisms of
wax-resin linings.
CONCLUDING THOUGHTS AND
MOVING FORWARD ACKNOWLEDGMENTS
In most cases, FTIR is simply not suitable for characterizing Support for the two research trips to the Winterthur
most of these potentially complex recipes. It was also Museum was provided by the WUDPAC Edward and
difficult to detect the presence of synthetic waxes in many Elizabeth Goodman Rosenberg Award. WUDPAC and
of the samples using GC/MSD. This may depend on the University of Delaware scientists and conservators who
type of wax, the amount, or even the age of the sample assisted with the analysis collection and data
itself. Sampling excess wax-resin adhesive from all interpretation include Dr. Mike Szelewski, Dr. Rosie
unidentified textile linings is impractical, but the Grayburn, and Dr. Jocelyn Alcántara-García. The authors
reconstructions and analysis prove that even when known would also like to thank Joy Gardiner (Charles F. Hummel
materials are present, they are not readily identified. It is Director of Conservation at the Winterthur Museum,
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Garden, and Library) for releasing this research for Intermuseum Conservation Association, Ann Creager
publication. Conservation, Nina A. Roth-Wells LLC, and Pinova Inc., a
subsidiary of DRT (Dérivés Résiniques et Terpéniques).
External institutions and private practice conservation
studios also donated their time and materials to the SAAM NOTES
wax-resin lining research project. Most of these donations
were coordinated in response to SAAM’s April 2019 “Call 1. 7-oxo-dehydroabietic acid always accompanies dehydroabietic acid, but
for Wax-Resin Materials” posting on the American Institute not vice versa; the former tends to be present only after a sample has
for Conservation Higher Logic community platform. degraded and/or been subjected to extreme heat.
External collaborators included Lauren Bradley and Josh
Summer at the Brooklyn Museum, Barbara Ramsay and Back Next
Elizabeth Robson at the John and Mable Ringling Museum    
of Art, Andrea Chevalier and Charles Eiben at the
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