CHRISTINE ROMANO, THOMAS LAM, and JIA-SUN TSANG
Technical Study and Treatment of Paintings by Clementine Hunter
ABSTRACT 
Twenty-two paintings by self-taught artist Clementine Hunter (1886 or 1887–1988) underwent treatment, analysis, and framing prior to 
exhibition at the National Museum of African American History and Culture. The examination of works ranging from the 1950s to 1980s 
revealed the artist’s use of underdrawing as well as her evolving technique. Analysis detected the presence of zinc soaps in passages of paint exhibiting 
unusual morphologies and protrusions in the painting Zinnias, ca.1970. Materials were documented and compared with previous analyses carried 
out on known Hunter paintings from a concluded Federal Bureau of Investigation forgery case. The exhibition and framing of selected works are also 
explored.
1. INTRODUCTION 2. TECHNIQUE
The 23 paintings by Clementine Hunter (1886 or 1887–1988) The paintings in the NMAAHC collection were executed 
represent the largest number of works by a single artist in the primarily in oil on a variety of supports, including plywood, 
National Museum of African American History and Culture cardboard, Masonite, paperboard, and a fabric window shade. 
(NMAAHC) collection. Clementine Hunter has become Clementine Hunter typically began a painting by drawing 
known as one of the most important American folk artists of the composition in graphite—a step she referred to as 
the 20th century. Born in Natchitoches Parish, Louisiana, “marking” the painting (Shiver and Whitehead 2012). An 
Hunter spent much of her life as a farm laborer and domestic example of Hunter’s compositional marking can be seen on 
servant at the Melrose Plantation along the Cane River. She the reverse side of Dancing, ca.1970, which was discovered 
began painting in 1939 around the age of 52 and is estimated after the painting was unframed for treatment (fig. 2). 
to have created over 5,000 works of art prior to her death in 
1988 (Shiver and Whitehead 2012). Known to paint on In her earlier works, Hunter painted with lean, economical 
window shades, ceramic jugs, cardboard, and other readily washes of color. According to Shriver and Whitehead (2012), 
found materials, Hunter often depicted scenes of work, Clementine Hunter made her first paintings using the dregs 
religious ceremonies, flowers, and memories from life at the of oil paint tubes discarded by Alberta Kinsey (1875–1952), 
Melrose Plantation (fig. 1) (Morgan 2005). Hunter an impressionist artist who painted while in residence at 
eventually gained recognition for her work and was awarded Melrose Plantation in the late 1930s. From this early period 
an honorary doctorate of fine arts from Northwestern State until around the mid-1950s, Hunter tended to first paint her 
University in 1985. “marked” figures and then fill in the background around 
them. Later in her career, Hunter began a work by laying in 
The NMAAHC works, acquired between 2012 and 2017, a wash of color overtop her marked compositions. As she 
were found to be in varying conditions, many with gained recognition and access to materials, Clementine 
significant accumulations of surface grime and localized areas Hunter’s technique gradually gave way to a wet-into-wet 
of cracking that necessitated cleaning and stabilization. A paint application, with heavy impastos on details of flowers, 
technical study was undertaken when deterioration in the clothing, and cotton bolls for which she is best known. The 
form of protrusions, cracking, and waxy, translucent passages progression of Hunter’s signature is also well documented. 
of paint was observed on three paintings. The investigation Her earliest works were signed “Clemence” by friend and 
sought to characterize the artist’s materials and identify the supporter Francois Mignon. Hunter began signing her 
underlying causes of deterioration in order to inform initials “CH” in the late 1940s to early 1950s (fig. 3a) 
strategies for treatment and exhibition. (Barabe 2012). In the 1960s, she reversed the “C” and 
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2  CHRISTINE ROMANO, THOMAS LAM, and JIA-SUN TSANG
paint samples were obtained from edges and areas of loss 
from these three paintings, mounted in cross-section, and 
analyzed with reflectance µ-Fourier transform infrared 
spectroscopy (µ-FTIR) [1] and scanning electron 
microscopy–energy dispersive x-ray spectroscopy (SEM-
EDX) [2] in order to characterize the materials and 
degradation products. Loose samples of paint associated with 
the cross-sections were analyzed with attenuated total 
reflection (ATR) FTIR where possible. Additionally, 22 of 
the 23 paintings were analyzed with portable XRF to 
qualitatively characterize the pigments present (one painting 
remained on view for the duration of this project). The 
results of these analyses indicate a modern palette containing 
both mineral-based and organic pigments (Table 1). 
Figure 1. Clementine Hunter, Zinnias, ca.1970, oil on paperboard,  Analysis of the binder with FTIR showed that oil paint was 
40.3 × 61 cm, Collection of the Smithsonian National Museum of used in all except one painting, Going to Church, ca. 1950s, 
African American History and Culture, Gift from the Collection of which had a casein binder. Three paintings, Zinnias, Wash Pot 
Sabra Brown Martin, © Cane River Art Corporation, Object No. Scene, and Dancing, all from the 1970s, exhibited paint 
2017.68.13 degradation in the form of protrusions, waxy-textured and 
wrinkled paint, a crystalline efflorescence, and localized 
gradually decreased the space between the letters, with the cracking. For the purpose of this postprint, only the 
backwards “C” eclipsing the “H” in the 1980s (figs. 3b–3d). degradation phenomena observed in Zinnias will be presented. 
The time period in which the NMAAHC paintings were 
created could be approximated using this system. 3.1 Zinnias, 1970s
Zinnias (fig. 1) was observed to be in stable structural 
condition, with an overall layer of surface grime and debris. 
3. ANALYSIS The work was executed in oil on an unprimed, 3/16-in. 
thick, four-ply laminated paperboard panel known as Upson 
As paint degradation was noted in three works from the board, identifiable by a green finishing sheet on the verso 
1970s, several other paintings from the same time period in (U.S. vs. William Toye 2010). It is signed “CH” (with a 
the NMAAHC’s collection were examined and compared. backward “C”), painted into wet paint toward the lower 
In collaboration with conservation scientists at MCI, discreet right. The work was executed with thick and thin passages of 
paint with visible brushstrokes and some color mixing done 
directly on the painting. Characteristic of the artist’s working 
method, several fingerprints are present along the edges 
where it was handled while still wet. 
Closer examination with optical microscopy revealed several 
passages of degradation and unusual paint morphology [3]. 
The red and green passages of paint exhibited the most 
significant states of deterioration, particularly in areas where 
they were layered over one another. Among the notable 
features, waxy agglomerations were observed below the paint 
layer in areas of loss (figs. 4a, 4f ). Brushstrokes that dried 
with a ribbon-like, wrinkled texture were found on the 
surface of the red paint as well as where green was layered 
over the red (figs. 4b, 4d). In addition, cracks were noted in 
Figure 2. Drawing on verso of Clementine Hunter’s Dancing, ca. 1970s, 
oil on paperboard, 17.1 × 30.3 cm, Collection of the Smithsonian red and green passages, and protrusions were observed 
National Museum of African American History and Culture, Gift between the yellow and green paint layers (figs. 4c, 4e). A 
from the Collection of Sabra Brown Martin, © Cane River Art white, crystalline efflorescence found near cracks was 
Corporation, Object No. 2017.68.9 identified as stearic acid, a free fatty acid, by FTIR (fig. 4b). 
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 Technical Study and Treatment of Paintings by Clementine Hunter 3
Figure 3. Details of the progression of Clementine Hunter’s signature: a. Wash Day, ca. 1950s; b. Baptism Scene, ca. 1960s; c. Zinnias, ca. 1970s; d. 
Black Jesus, ca. 1980s.
Table 1. Selection of Pigments Characterized in Clementine Hunter Paintings from the NMAAHC Collection
White Black Red Orange Yellow Brown Green Blue Violet Fillers
Titanium Ivory Cadmium Cadmium Cadmium Raw/ Viridian or Prussian Organic Barium 
white black red orange yellow burnt chromium- blue (in violet sulfate
umber based green one early 
work)
Zinc Mars/ Organic Organic Organic Iron  Organic green Organic Calcium 
white iron red orange yellow earths blue carbonate
black
Lead Cadmium green Manganese Zinc oxide
white or Cadmium blue
yellow + 
organic
Lithopone 
(possibly)
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4  CHRISTINE ROMANO, THOMAS LAM, and JIA-SUN TSANG
Figure 4. Details of degradation and unusual paint morphologies in Zinnias: a. Waxy agglomerations within loss; b. Wrinkled, ribbon-like paint and 
efflorescence; c. Lifted cracks; d. Wrinkled, ribbon-like paint; e. Protrusion and cracking; f. Waxy agglomerations on underside of paint.
FTIR analysis also indicated that the red and green passages (CH ) absorptions at 2918, 2849, 1456, 743, and 722 cm–1 
2
contained organic, dye-based pigments and crystalline zinc (Robinet and Corbeil 2003). The lack of a broad absorption 
soaps. The FTIR spectrum of a wrinkled, waxy around 1580–1590 cm–1 suggests that the zinc stearate is 
agglomeration from an area of loss is compared to zinc present in the sample as a crystallized zinc soap (Hermans 
stearate in figure 5. The red agglomeration sample shares et al. 2016).
several characteristic peaks with zinc stearate, including 
carboxylate stretches at 1538 and 1396 cm–1, and methylene 3.2 Sample X4: Protrusion
The protrusion shown in figure 4e was removed from the 
painting, mounted in cross-section (referred to in this section 
as Sample X4), and analyzed with SEM-EDX. An adjacent 
paint sample was analyzed with ATR-FTIR and found to 
contain both crystalline and amorphous zinc carboxylates. 
The optical image in figure 7a shows a lower black layer, a 
yellow and red protruding layer, and a portion of the green 
paint through which the protrusion emerged. The upper left 
portion of the yellow layer is translucent. 
The pigments and fillers can be characterized based on 
elemental mapping, shown in figure 6b. The lower black 
layer containing both calcium and phosphorus (indicated in 
yellow) is presumed to be bone black; the top green layer 
(indicated in green) contains a chromium-based pigment, 
such as viridian; the yellow layer is abundant in zinc 
(indicated in red) and likely contains a dye-based yellow 
pigment with zinc oxide fillers, based on the absence of other 
Figure 5. Comparison of FTIR spectra of the red waxy, wrinkled elements. Finally, barium sulfate filler particles (indicated in 
agglomerations from Zinnias and synthetic zinc stearate blue) are present in the lower portion of the sample. 
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 Technical Study and Treatment of Paintings by Clementine Hunter 5
Figure 6. SEM-EDX analysis of a protrusion from Zinnias: a. Optical image; b. Composite EDX maps for zinc (red), barium (blue), sulfur (blue), 
chromium (green), calcium (yellow) and phosphorus (yellow); c. Intensity map showing concentrations of chlorine within paint cross-section; d. 
Back-scattered electron micrograph with the regions of interest selected for EDX analysis in black (Area 1) and red (Area 2) boxes; e. Correspond-
ing EDX spectra for the black (Area 1) and red (Area 2) boxed regions of interest selected in (d).
SEM-EDX also detected distributions of chlorine in the phthalocyanine) may also be a component. The presence of 
green and yellow layers of the protrusion (fig. 6c). Shown in chlorine detected in low abundance within the yellow layer, 
an intensity map (where red indicates a relatively high and however, is less easily explained. Overlaid spectra from two 
blue indicates a relatively low concentration), chlorine is regions of interest, indicated by a black and red box in figure 6d, 
especially abundant in the green chromium-containing paint are compared with figure 6e. The red boxed region (Area 2), 
layer, suggesting a chlorine-containing pigment such as representing a zinc-rich area, has more counts of zinc, and 
phthalo green (copper(II) complex with chlorinated fewer counts of chlorine and carbon than the spectrum for 
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6  CHRISTINE ROMANO, THOMAS LAM, and JIA-SUN TSANG
Figure 7. a. Optical image of the region where the reflectance µ-FTIR map was performed; b. Reflectance µ-FTIR component map image from 
nonnegative matrix factorization (NMF); c. Reflectance µ-FTIR component spectrum from NMF image where the dashed lines at 1562 cm–1, 
1470 cm–1, and 1400 cm–1 are characteristic features for discussion.
the black-boxed region (Area 1). The protrusion’s the green paint layer, the zinc-rich area of the protrusion 
distribution of zinc through an otherwise carbon-rich layer layer, and the carbon-rich area of the protrusion layer (shown 
and the detection of zinc carboxylates in a nearby passage of in fig. 7b as gradients of dark blue, green, and yellow, 
the same material suggest that the protruding layer contains respectively). Figure 7c shows a component reflectance 
zinc soaps. Further, is it possible that the chlorine detected in spectrum, with the representative phase indicated by different 
the protruding layer may be associated in some way with color gradients. In this instance, the most zinc soap rich areas 
–
metal soaps, as it has been detected at the core of lead soap appear yellow, while materials that are the most contrasting 
protrusions by other researchers (Keune and Boon 2007). in composition (i.e., the green paint passage at the right side 
of the sample) are represented in dark blue. Characteristic 
In addition to ATR-FTIR and SEM-EDX, reflectance asymmetric carboxylate stretches (ν  COO, 1558 cm–1) and 
a
µ-FTIR mapping was carried out on the same mounted symmetric carboxylate stretches (ν  COO, slightly shifted to 
s
protrusion cross-section (Sample X4). The purpose of 1470 cm–1) and the CH bending typical in zinc stearate (δ 
2 
performing reflectance µ-FTIR mapping was to create a CH , at approximately 1400 cm–1) are observable.
2  
visual map of the protrusion’s organic material phases for 
correlation with inorganic data from SEM-EDX. Reflectance Visualizing both the inorganic and organic phases within the 
FTIR is a comparatively noisier technique than ATR-FTIR protrusion allowed us to approximate a scenario for the 
owing to atmospheric and specular interference. Therefore, a protrusion’s development. Presuming that the yellow paint 
nonnegative matrix factorization was applied to the layer was once flat rather than protruding, the distribution of 
reflectance µ-FTIR map using HyperSpy, an open-source the layer’s zinc oxide particles (fig. 6d) in relation to the 
library for the programming language Python. The carbon-rich areas illustrates a path of upward migration of 
component optical image (top left) and component µ-FTIR zinc soaps, which corresponds with the upward eruption of 
map (bottom left) related to the yellow layer of the protrusion the protrusion. It is also possible that the pigment volume 
(in which SEM-EDX detected carbon, zinc, and chlorine) are concentration of the organic yellow pigment in the 
presented in figures 7a and 7b. The pixelated appearance of protrusion layer was relatively low owing to the small 
figure 7b is caused by the 40 × 40 µm aperture of the particle size, thus allowing for the comparatively greater 
reflectance FTIR setup. Despite this, the map accurately amount of linseed oil and associated fatty acid species to react 
shows three main material components of the cross-section: with the zinc oxide filler. 
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 Technical Study and Treatment of Paintings by Clementine Hunter 7
In order to further support our analyses, expert analytical were cleaned and stabilized. As many of the colors analyzed 
reports were obtained from a concluded 2012 Federal Bureau contained zinc carboxylates or exhibited water sensitivity, 
of Investigation (FBI) case that investigated suspected dry cleaning was carried out with cosmetic sponges, Mr. 
Clementine Hunter forgeries. The documents included Clean melamine sponges, and a semirigid Pemulen-based gel 
technical studies carried out by two well-known analytical (applied only where it was safe to clear with water). Crushed, 
firms (Orion Analytical and the McCrone Group) in which distorted edges of laminated paperboard supports were 
suspected forgeries were compared with paintings by Hunter consolidated with wheat starch paste and brought back into 
with established provenance. The suspected and known plane using gentle weight. Areas of loss were inpainted using 
paintings were analyzed to identify differences in technique, chalk pastels, watercolor, and gouache. Each of the works 
pigments, supports, and surface characteristics using optical was documented before, during, and after treatment with 
microscopy, polarized light microscopy, SEM-EDX, FTIR, detailed photographs and reports.
and Raman spectroscopies. Among the differences were the 
detection of dolomite (anhydrous calcium magnesium One work in particular, Window Shade, ca.1950s, required 
carbonate) in the forgeries and the student-grade paints seized structural treatment. The painting, which was executed on a 
from the house of the now-convicted forger (U.S. vs. William thin canvas window shade with a commercially prepared 
Toye 2010). Data related to pigments and additives from the oil-containing surface, had been glued, stapled, and sewn to 
genuine paintings in the FBI case were found to correlate well a fabric-covered Fome-Cor board along the painting’s 
with that obtained from the NMAAHC paintings, providing bottom edge and on either side of the top roller bar. In 
further confirmation of Hunter’s palette and working methods. addition, the window shade support exhibited distortions 
from years of uneven tension as well as staining and tidelines 
from previous contact with water. The painting was 
4. TREATMENT AND FRAMING unframed, mechanically removed from its backing, and the 
front and back surfaces were dry cleaned using cosmetic 
The group of 22 paintings by Clementine Hunter were sponges. Areas of loss and staining were inpainted using 
examined and individually tailored treatment strategies were gouache and pastels. In spite of local and overall 
proposed and undertaken for each work. Following humidification attempts, distortions continued to return in 
documentation, the unvarnished surfaces of each painting the support. Following consultation with curators, the 
Figure 8. Mounting for framing and exhibition of Clementine Hunter’s Window Shade.
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8  CHRISTINE ROMANO, THOMAS LAM, and JIA-SUN TSANG
decision was made to line the window shade to an auxiliary 
lightweight lining fabric that could also be used in the 
painting’s exhibition mount (fig. 8). 
A number of lining tests were carried out on mockups of 
similar materials. A polyester monofilament fabric (from 
TestFabrics) was chosen as a lining support, as mockup tests 
confirmed that BEVA 371 film adhesive remained 
preferentially adhered to the polyester lining fabric when 
peel reversed from canvas. The roller bar was removed from 
the window shade, and the painting was humidified overall 
prior to the lining. The painting was then lined to the 
polyester fabric on a heated vacuum suction table using a 
single sheet of BEVA 371 film as the adhesive. 
The decision to honor the material origins of the window 
shade dictated the approaches to mounting the work for 
exhibition. In order to reattach the roller bar, a portion of the 
lining was mechanically reversed with a spatula along the top 
edge and trimmed to where the composition was intended to 
begin. An edge lining of the same polyester fabric and BEVA 
371 was attached to the top edge of the painting and adhered 
to the roller bar, which had been isolated with polyester film. 
The top edge was restapled using original holes, and the top 
portion was rerolled.
Next, excess polyester lining canvas along the bottom edge 
was folded into a pocket and secured to the verso. A 1/8-in. 
piece of plexiglass (3/4 in. in height) spanning the lower 
length of the window shade was inserted into the pocket on Figure 9. Clementine Hunter, Window Shade, ca.1950s, oil on window 
the verso in order to create an anchoring point that added shade, 102.1 × 91.1 cm (image area), displayed in exhibition frame 
gentle downward weight to the mounting system while also constructed by Eric Dixon, NMAAHC. Collection of the Smithson-
allowing for the work to be read as fabric, with a naturalistic ian National Museum of African American History and Culture, Gift 
drape. Finally, the excess lining fabric was passed through of the Rand and Dana Jack family, in honor of Rand’s grandmother, 
Blythe Rand, who early recognized and supported the special talents 
vertical slits cut in a Hexamount archival honeycomb paper of Clementine Hunter, © Cane River Art Corporation, Object No. 
panel, tensioned, and attached to the verso, employing a 2014.176.1
method similar to pass-through hinges used in float-
mounting works on paper. The roller bar was attached to the 
Hexamount panel using plexiglass “tombstones” fabricated stack of archival ragboard (chosen to absorb acids and to act 
in-house at the NMAAHC. The painting was framed and as an environmental buffer), with a window mat placed 
placed into a secondary exhibition frame intended to invoke slightly lower than the height of the artwork, allowing space 
a window molding (fig. 9). for the edges of the painting to be seen. The second frame 
type, designed for larger works, comprised a wood backing 
painted the same color as the window mats (fig. 10). In both 
5. FRAMING styles, the works were secured to their mounts with custom-
bent stainless steel headless pins covered by Teflon tubing. 
Of the 22 works treated, 13 were mounted and framed for The pins were pressure fitted into predrilled holes in the 
the exhibition in collaboration and consultation with wood backings as well as the laminated stacks of ragboard. 
numerous curatorial, collections, and design professionals The paintings were glazed and exhibited in walnut frames. 
within the Smithsonian. Apart from the window shade, the As a result of this framing process, the paintings, many of 
paintings were all executed on acidic supports, including which were small, were afforded sufficient visual space, with 
paperboard and plywood. Two types of frames were evidence of the artist’s handling of the edges visible to the 
designed: the first featured a sink mount made of a laminated viewer.
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 Technical Study and Treatment of Paintings by Clementine Hunter 9
Figure 10. a. Custom frame style #1 includes a window mat placed slightly lower than the artwork, held by pins drilled into a stacked ragboard 
backing; b. Clementine Hunter, Wedding, ca.1970s, oil on paperboard, 17.5 × 18.4 cm, Collection of the Smithsonian National Museum of African 
American History and Culture, Gift from the Collection of Sabra Brown Martin, © Cane River Art Corporation, Object No. 2017.68.10; c. 
Custom frame style #2, a painted wood backing into which pins are drilled to support the artwork; d. Clementine Hunter, African House, ca.1970s, 
oil on plywood, 15.2 × 20.5 cm, Collection of the Smithsonian National Museum of African American History and Culture, Gift from the 
Collection of Sabra Brown Martin, © Cane River Art Corporation, Object No. 2017.68.5. Frames constructed by FramesByRebecca, Inc. 
6. CONCLUSIONS data, red and green dye-based paints in Zinnias, ca.1970s, 
contained zinc oxide fillers that reacted with the oil binder to 
The comparison and study of Clementine Hunter’s paintings form zinc soaps. Crystalline zinc soaps were detected in 
within the NMAAHC’s collection has revealed insights into waxy agglomerations and translucent, wrinkled paint 
the artist’s evolving style and use of materials. Based on the passages. The dye-based colors appear to exhibit more zinc 
analysis carried out for both the NMAAHC paintings and soap–related degradation compared with mineral-based 
genuine works by Hunter in an FBI study, Hunter appears to pigments, possibly owing to their small particle size and 
have used high-quality oil paint lacking dolomite fillers estimated low pigment volume concentration. In addition, 
typically found in student-grade paints. Her paints contained low concentrations of chlorine were noted in more than one 
both mineral and organic pigments. In three paintings, cross-section containing paint affected by zinc soaps. Future 
passages of paint containing zinc soaps also exhibited work related to the effects of zinc-containing fillers on 
degradation and unusual morphologies. Based on SEM-EDX modern paints is needed. 
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10  CHRISTINE ROMANO, THOMAS LAM, and JIA-SUN TSANG
The works were treated with little to no use of water, as U.S. vs. William Toye, et al. 2010. 8:05-cr-00442 (District 
aqueous and solvent cleaning has been linked to the Court, D. Maryland 2012). Expert reports prepared by 
propagation of zinc soaps (Osmond 2012). The works Orion Analytical and McCrone Associates, Inc. 
were mounted and framed to honor the artist’s use of 
materials as well as to absorb acidic materials from the 
paintings’ supports and buffer from environmental FURTHER READING
fluctuations. 
Deaton IV, Randolph J. 2012. “FBI Investigation of 
Clementine Hunter Forgeries.” Paper presented at Divine 
ACKNOWLEDGMENTS Disorder: Conference on the Conservation of Outsider and Folk 
Art, National Center for Preservation Technology and 
The authors wish to thank Dr. Reneé Anderson, Dr. Training, Natchitoches, LA, February 15–16, 2012. 
Jacqueline Serwer, and Dr. Tuliza Fleming for their support https://www.ncptt.nps.gov/blog/fbi-investigation-of-
and collaboration in the study and conservation of these clementine-hunter-forgeries-by-william-toye/ 
works. Many thanks to FramesByRebecca, Inc. and Shelly Woods Jr., Naurice Frank. 2013. “Kindred Spirits of the 
Uhlir (National Museum of the American Indian) for their Imagination: Henry Ossawa Tanner and Clementine 
mounting and framing contributions, as well as Gina Hunter.” 455–465. Accessed June 28, 2020. http://www.
Whiteman, Eric Dixon, Andrea Medalie, and the jstor.org/stable/pdf/10.5323/jafriamerhist.98.3.0455.pdf
NMAAHC designers and collections staff who contributed 
to the exhibition. A special thanks to Dr. G. Asher Newsome 
and the staff at the Smithsonian Museum Conservation NOTES
Institute for their analytical support. 
 1. µ-FTIR noncontact mapping in reflectance mode was 
carried out with a Thermo Nicolet 6700 FTIR 
REFERENCES spectrometer equipped with a mercury cadmium 
telluride type A (MTC-A) detector, in addition to 
Barabe, Joseph G. 2012. “Discriminating Palettes: The ATR-FTIR. The mapping analysis of the embedded 
Painting Materials of Clementine Hunter and Her samples was carried out in a reflection mode with 500 
Imitator.” In Postprints of the Paintings Specialty Group, scans taken from 4,000 cm–1 to 650 cm–1 at a spectral 
Vol. 25. Washington, DC: American Institute for resolution of 1.928 cm–1. Mapping on uncorrected data 
Conservation of Historic and Artistic Works. 31–41. was performed using a 40 µm × 40 µm aperture with 
Hermans, Joen J., Katrien Keune, Annelies van Loon, an overlapping step size of 20 µm in the x and y axes. 
Robert W. Corkery, and Piet D. Iedema. 2016. “Ionomer- The FTIR maps were analyzed using HyperSpy version 
like Structure in Mature Oil Paint Binding Media.” RSC 1.5.2, an open-source Python-based software package 
Advances 6 (96): 93363–93369. for hyperspectral data processing (www.hyperspy.org). 
Site-specific samples were also extracted for ATR-
Keune, Katrien, and Jaap J. Boon. 2007. “Analytical Imaging 
FTIR and transmission through an infrared microscope 
Studies of Cross-Sections of Paintings Affected by Lead 
(µ-FTIR) using the Thermo Nicolet 6700 FTIR 
Soap Aggregate Formation.” Studies in Conservation 52 (3): 
spectrometer with Golden Gate ATR and MTC-A 
161–76.
detector. The data were collected at 4 cm–1 spectral 
Morgan, Stacy. 2005. “Clementine Hunter and Melrose resolution, using 64 scans in ATR-FTIR mode.
Plantation.” American Art 19 (1): 25–28. Accessed April 
 2. SEM-EDX was performed on carbon-coated embedded 
30, 2019. http://www.jstor.org/stable/pdf/10.1086/ 
samples in high-vacuum mode using a Hitachi 
429972.pdf
S3700-N scanning electron microscope (SEM). EDX 
Osmond, Gillian. 2012. “Zinc white: A Review of Zinc was performed using a Bruker XFlash 6|60 detector 
Oxide Pigment Properties and Implications for Stability with Esprit software version 2.1.2.17832. Samples were 
in Oil-Based Paintings.” AICCM Bulletin 33 (1): 20–29. analyzed at a 15-kV primary electron accelerating 
Robinet, Laurianne, and Marie-Claude Corbeil-a2. 2003. voltage. 
“The Characterization of Metal Soaps.” Studies in  3. Microscopy was performed with a HIROX KH-8700 
Conservation 48 (1): 23–40. digital microscope with the MXG-2500REZ dual 
Shiver, Art, and Tom Whitehead. 2012. Clementine Hunter: illumination lens and 2.11 megapixel CCD sensor. The 
Her Life and Art. Baton Rouge, LA: LSU Press. microscope is equipped with a motorized z control, 
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 Technical Study and Treatment of Paintings by Clementine Hunter 11
which allows for the collection of a focal stack that can THOMAS LAM
be rendered into a three-dimensional image with the Physical Scientist
HIROX KH-8700 embedded proprietary operating Smithsonian Institution
system and software package. Museum Conservation Institute 
4210 Silver Hill Road
Suitland, MD 20746
AUTHORS lamt@si.edu
CHRISTINE ROMANO
Paintings Conservation Fellow JIA-SUN TSANG
Smithsonian Institution Senior Paintings Conservator
National Museum of African American History and Culture Smithsonian Institution
Museum Conservation Institute Museum Conservation Institute 
4210 Silver Hill Road 4210 Silver Hill Road
Suitland, MD 20746 Suitland, MD 20746
romanoc@si.edu tsangj@si.edu
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