BIERSTADT'S LATE PAINTINGS: METHODS, MATERIALS, AND MADNESS
DARE MYERS HARTWELL
ABSTRACT—In his late paintings Albert Bierstadt (1830–1902) experimented with materials and techniques not found in the more technically orthodox paintings of his heyday. His choice of materials has sometimes had a deleterious effect on the appearance and condition of these paintings. Graphite paint, used as a ground layer, was by far the most unusual of these materials. It seems likely that Bierstadt decided to experiment with graphite as a protective coating for painting canvas because contemporary advertisements recommended it for weatherproofing and preserving exterior canvas coverings. His use of panel-back stretchers and a letter written by him indicate his concern for protecting the painting canvas. The surface texture of many of Bierstadt's late paintings also suggests that he may have experimented with paint media, including perhaps an oil and water emulsion. For surface coatings in this period, Bierstadt recommended poppy oil and a varnish of copal dissolved in turpentine.
TITRE—Les derniers tableaux de Bierstadt: méthodes, matériaux et folie. RÉSUMÉ—Au cours des dernières années de sa vie, Albert Bierstadt (1830–1902) employa des matériaux et des techniques de peinture s'éloignant des techniques plus traditionnelles qu'il utilisait à l'apogée de sa carrière. Le choix de ces matériaux a parfois eu de mauvaises répercussions sur l'apparence et la stabilité de ces tableaux. La peinture à base de graphite qu'il utilisait en guise de couche préparatoire est sans doute le matériau le plus insolite. II semble que Bierstadt ait décidé d'adopter le graphite pour protéger ses toiles à cause de publicités de l'époque qui recommandaient ce matériau pour imperméabiliser et préserver les bâches. L'emploi de chassis à clefs avec panneau incorporé et une de ses lettres démontrent sa préoccupation pour protéger la toile de ses tableaux. La surface de nombreux tableaux tardifs de Bierstadt suggère aussi qu'il a essayé divers liants, comme peut-être une émulsion à base d'huile et d'eau. Durant cette période, l'artiste recommendait l'usage de l'huile de pavot et d'un vernis de copal dissout dans de l'essence de térébenthine pour protéger la surface de ses tableaux.
TITULO—Las pinturas tardías de Bierstadt: métodos, materiales, y locura. RESUMEN—En sus pinturas tardías Albert Bierstadt (1830–1902) experimentó con materiales y técnicas no encontradas en las pinturas más técnicamente ortodoxas de su período de apogeo. Su selección de materiales a veces ha tenido un efecto nocivo en la apariencia y condición de estas pinturas. La pintura a base de grafito, usada como capa de preparación, fue definitivamente el más inusitado de estos materiales. Es probable que Bierstadt decidiera experimentar con el grafito como recubrimiento protector para los lienzos de pintar debido a que los anuncios contemporáneos lo recomendaban para impermeabilizar y preservar los recubrimientos de lonas para uso al aire libre. Su empleo de bastidores con paneles por detrás y una carta escrita por él indican su preocupación por proteger los lienzos para pintar. La textura superficial de muchas de las pinturas tardías de Bierstadt también sugieren que pudo haber experimentado diferentes medios, incluyendo quizás una emulsión de aceite y agua. Como recubrimiento superficial en este período, Bierstadt recomendaba aceite de amapola y un barniz de copal disuelto en trementina.
Albert Bierstadt was at the height of both his artistic powers and his popularity in the 1860s. By 1874, however, critics and public alike found him passé, and although he countinued to produce paintings of quality, it is obvious that his artistic abilities were also in decline (Hendricks 1988). Nevertheless, technical examinations of his late paintings have revealed important information about his working methods as well as his tendency to experiment with materials in his decline, and it is on certain of these materials that I will focus here.
This investigation into Bierstadt's working methods and materials was precipitated when both versions of Bierstadt's most important late painting, The Last of the Buffalo, underwent conservation at approximately the same time, affording the conservators involved in their treatment a unique opportunity to compare the two pictures (Hartwell and Parkin 1999). The painting in the collection of the Corcoran Gallery of Art, Washington, D.C., was treated by the author; the version belonging to the Buffalo Bill Historical Center in Cody, Wyoming, was treated by Helen Mar Parkin and Perry Huston of Perry C. Huston and Associates, Inc., Fort Worth, Texas.
The two paintings are very close in size and composition, and comparison of cross sections taken from both of them show a similar layer structure of thick lead-white preparation over which one or more thin, relatively opaque layers of oil-based paint build up the design (figs. 1, 2). The pigments analyzed in each painting also proved to be the same (Berrie and Palmer 1986, 1988a, 1988b). Nevertheless, in the Cody picture there is an additional layer, highly refelective and almost black in color, between the lead-white preparation and the canvas. No traces of this layer are found in the Corcoran painting.
Albert Bierstadt, The Last of the Buffalo, 1888, oil on canvas. 180.5 × 301.5 cm (71 1/8 × 118 3/4 in.), Corcoran Gallery of Art, Washington, D.C., gift of Mary (Mrs. Albert) Bierstadt, 1909, acc. no. 9.12. Photomicrograph of a cross section from the blue sky, 418×. Photograph by Michael R. Palmer
Albert Bierstadt, The Last of the Buffalo, 1888, oil on canvas. 152.8 × 245.2 cm (60 1/4 × 96 1/2 in.), Buffalo Bill Historical Center, Cody, Wyoming, acc. no. 2.60. Photomicrograph of a cross section from the blue sky, 418×. Photograph by Michael R. Palmer
The black layer is continuous in the Cody picture. At the time of the treatment it was visible in areas of extensive abrasion, in the craquelure, and at the edges of the painting. Parkin and Huston speculated in the treatment report that the layer was “possibly graphite” because of its shiny, metallic appearance (Parkin and Huston 1985). After the cross sections were taken and the Scientific Research Department of the National Gallery of Art was asked to analyze the black layer because of its peculiar appearance, the preliminary identification was confirmed. The dark layer is a mixture consisting primarily of graphite with some clay and trace amounts of red iron oxide in linseed oil (Lomax 1989; Palmer 1989).
2 GRAPHITE GROUNDS
To find a layer of graphite oil paint in a painting is unusual to say the least, and leads to the question of its purpose. In the Cody version of The Last of the Buffalo, it plays no role in the intended appearance of the picture, covered over as it is by the thick lead-white layer.
Curiosity led me to pursue the matter by inquiring among my colleagues for other examples of paintings with graphitelike ground layers, either by Bierstadt or other artists of the period. Eventually I was able to identify a small group of such works—all by Bierstadt—and to obtain samples of the ground layers on four of them: Rocky Mountain Sheep(fig. 3); Indian Sunset: Deer by a Lake(fig. 5); Weeping Oaks, Clear Creek, California(figs. 4, 6); and View of Point Lobos at Sunset (private collection). A view of Old Faithful (at the Kennedy Galleries, New York, in 1991) also has a graphite ground, and graphite grounds are suspected for a few other Bierstadt paintings that it was not possible to examine closely.
Albert Bierstadt, Rocky Mountain Sheep oil on canvas. 128.2 × 108.5 cm (50 1/2 × 42 3/4 in.), private collection. Photomicrograph of a cross section of the sky, 198×. Photograph by Michael R. Palmer
Albert Bierstadt, Weeping Oaks, Clear Creek, California, photomicrograph of a crushed pigment sample of graphite from the tacking margin, 576×. Photograph by Michael R. Palmer
Albert Bierstadt, Indian Sunset: Deer by a Lake, ca. 1880–90, oil on canvas. 77.2 × 113 cm (30 3/8 × 44 1/2 in.), Yale University Art Gallery, bequest of Evelyn A. Cummings, acc. no. 1971.111.1
Albert Bierstadt, Weeping Oaks, Clear Creek, California, 1880, oil on canvas. 91.4 × 132 cm (36 × 52 in.), University of Denver Art Collection, gift of Albert Bierstadt, 1891, acc. no. 1891.0001
The samples were analyzed using light microscopy and powder x-ray diffraction. In each case the black ground was found to be a mixture of graphite with some clay and trace amounts of iron ores (Palmer 1989; see appendix). Of the group of paintings with graphite grounds, all those that can be dated fall between 18801 and ca.1888, which is the date traditionally assigned to The Last of the Buffalo because it was painted for the Paris Exposition of 1889.
Unlike the Cody version of The Last of the Buffalo, however, none of these paintings has an interleaving white layer. The paint is applied directly on top of the graphite ground (see fig. 3). Moreover, because all four paintings are unlined, it was possible to see that the graphite coating had also been applied to the reverse of the canvas.
All four paintings are still mounted on their original stretchers, which have wood panels inset between the crossbars (fig. 7). This is the type of stretcher that Bierstadt typically used on his paintings. In addition, Indian Sunset: Deer by a Lake and Old Faithful are mounted on panel-back stretchers with corner springs intended to provide automatic expansion and contraction of the stretcher in response to changes in humidity. Wright and Gardner patented this spring stretcher in 1875, and their labels can often still be found on the stretchers. Wright and Gardner stretchers were made both with and without the inset panels, but I have observed only the former on Bierstadt's paintings.
Bierstadt, Rocky Mountain Sheep, panel-back stretcher. Courtesy of Perry C. Huston and Associates, Center for the Conservation of Art.
The question remains as to why Bierstadt used graphite paint as a preparation. Rocky Mountain Sheep is an exception in that the ground color does appear to provide luminosity to this night scene (Parkin and Huston 1985). In the other paintings, brightly colored paint covers the dark ground so that it plays no part in the design, and for the Cody version of The Last of the Buffalo, Bierstadt actually provided a light substrate for the paint by covering over the graphite with a second, lead-white preparation.
Graphite in dry form was available from at least the early part of the 19th century, and commercially prepared graphite and linseed oil paint became a common product toward the end of the century. Companies manufacturing the paint include the Joseph Dixon Crucible Co. in Jersey City, New Jersey; the Atlantic Paint Company and the Elko Paint Co. in New York City; the Wisconsin Graphite Co. in Pittsburgh, Pennsylvania; the National Paint & Varnish Co. and the Sherwin-Williams Co. in Cleveland, Ohio; the United States Graphite Co. in Saginaw, Michigan; and the Detroit Manufacturing Co. in Detroit, Michigan. The earliest reference that I found to commercial graphite paint is a sales receipt dated 1874 from New York Black Lead Works for “Patent Plumbago Paint,” plumbago being another name for graphite. Advertisements for the product remained plentiful well into the first quarter of the 20th century (Warshaw Collection).
Graphite paint appears to have been manufactured primarily as a protective coating for metal exposed to weather, but late-19th-century advertisements also recommend it for canvas, wood, brick, and paper (fig. 8). Its touted properties include durability, elasticity, and imperviousness to water, chemicals, gases, and climate changes. The 1895 advertisement reproduced from the Detroit Graphite Manufacturing Co. (Warshaw Collection) in figure 8 proclaims:
This is a photograph of a common two-bushel grain bag, painted with Superior Graphite Paint in July 1892, and kept constantly filled with water since, without leaking. The bag is still soft and pliable, and although frozen solid three times, is in perfect condition. It does not leak a drop, apparently good for many more years' service. What better evidence could there be of the waterproof and preservative qualities of Superior Graphite Paint?
Part of an advertising brochure for Superior Graphite Paint, Detroit Graphite Manufacturing Co., 1895. Courtesy of the Warshaw Collection of Business Americana, Archives Center, National Museum of American History, Smithsonian Institution, Washington, D.C.
It may be assumed that the “canvas” the advertisements recommend waterproofing with graphite paint is for items such as tents, awnings, and tarpaulins. However, Bierstadt may have been aware of the claims made for graphite paint, as in the advertisement illustrated here, and decided to experiment with it as a protective coating for painting canvas. The fact that the coating appears on both sides of the canvas would support this theory.
We know that Bierstadt was concerned with protecting the canvas on his paintings. The panel-back stretchers that he used throughout most of his career are evidence of this concern, and written confirmation also appears in one of his letters in the archives of the Corcoran Gallery. Making reference to a man named Volmering who appears to have been a restorer in New York, Bierstadt writes:
He says that in Berlin and Vienna the principle [sic] galleries have had the backs of the stretcher frames covered with calico or thin cloth and then covered with shellac and glue. This keeps out all moisture and dust and preserves the canvas. The panel back does the same and I generally have both sides covered with shellac before the canvas is put on. This prevents the wood from absorbing moisture in any way and I think it very rare that even in dry times the canvas remains tight whereas in the ordinary stretcher the canvas is tight or loose according to the weather.
This must be bad. The colors we use are not elastic like rubber, and consequently the picture must crack in time.…
It stands to reason that dirt in any form is bad for a picture, it is sure to rot the canvas in time and I have known of so much dirt collecting upon the back of a canvas as to sustain vegitable [sic] life. You can understand this when a picture hangs against a damp wall (Bierstadt 1877).
It does seem possible that Bierstadt was using graphite paint as a preparation and reverse coating to provide additional protection for the canvas against moisture and dirt. It is obvious that Bierstadt was both concerned and knowledgeable about the preservation of paintings, and in fact, the canvases, even extremely large ones, that he mounted on panel-back stretchers often still do not require lining after more than 100 years, testifying at least to the efficacy of panel-back stretchers.
The question remains, however, as to why Bierstadt used a graphite priming layer on the Cody but not the Corcoran version of The Last of the Buffalo. I can only hypothesize that by the late 1880s he had determined that graphite paint was an inappropriate priming layer for oil paintings. He covered it over with a leadwhite preparation in what is believed to be the first version of the picture and abandoned it altogether for the Corcoran painting (Hartwell and Parkin 1999).
In fact, the efficacy of graphite paint for any purpose appears to rely on many variables, including the type of graphite, the method of manufacture, and the presence of additives. Bierstadt used a paint made of crystalline, or “flake,” graphite, which does not readily mix with oil. Additives such as silica, iron oxides, or calcium carbonate were generally combined with the graphite to correct this problem, and that might explain the clay and iron oxides found in the samples taken from Bierstadt's paintings. Moreover, in the analytical report on these samples Palmer (1989, 43 in the appendix following this article) states, “Although the graphite ground (as it exists on the canvas support) appears to be a discrete layer, it should be noted that the individual flakes or plates of graphite are arranged layer upon layer. Furthermore these layers, as seen in cross-section, are in varying states of adhesion to one another.” It also appears that oil paint does not form a strong bond with such a ground layer.
With this in mind, it is not surprising to discover that paintings with graphite grounds are generally reported to be sensitive to solvents and difficult to clean, and they have often suffered major damage. Indian Sunset: Deer by a Lake is one of the few paintings in this group that appears to be in relatively good condition. Mayer examined the painting in 1988 and found both the ground and paint to be exceptionally soluble (Mayer and Myers 1988). Although the records of the Yale University Art Gallery state that the painting was “cleaned and restored” in 1972, there is an old, yellowed varnish underneath a more recent synthetic varnish layer. The original varnish might never have been completely removed, and this might account for the painting's having escaped the damage suffered by the others.
It is probable that Bierstadt had become aware of some of the problems with graphite paint by the time he began the Cody version of The Last of the Buffalo, which seems to be the last painting to contain a graphite ground layer. For example, many of the paintings with graphite grounds have wrinkling in the paint layer. This wrinkling probably occurred as the paint dried and suggests poor adhesion between the paint and ground layers. Bierstadt could have noticed this problem occurring during the approximately eight years in which he used graphite.
Furthermore, paintings in which the design layer is applied directly over the graphite ground have probably darkened, as oil paint becomes more transparent with time. Whether Bierstadt was aware of this phenomenon is impossible to say, but it is tempting to suggest that his use of the interleaving white layer on the Cody picture indicates as much. Certainly by the time he turned to the Corcoran version of The Last of the Buffalo, he had abandoned graphite paint altogether.
3 PAINT MEDIA AND SURFACE COATINGS
Some of Bierstadt's late paintings have varying types of surface texture that contrast to the smoother surfaces his paintings usually exhibit. This surface texture cannot be blamed on a graphite ground layer because it also occurs in paintings without graphite, for example in the Corcoran version of The Last of the Buffalo. The surface in this painting has a curiously granular appearance, and it is possible that Bierstadt may actually have textured the ground layer. The paint is somewhat powdery and seems to suffer from a lack of oil binding medium. There are pinpoint losses throughout the paint layer that appear to correspond to the tips of the textured ground and may be the result of mechanical action during previous cleanings. Other late paintings seem to have a thick, rich, slightly wrinkled texture in the paint layer. One possible explanation is that Bierstadt was experimenting with paints in this late period, at least sometimes with unfortunate results. He might even have tried some of the paints containing oil and water emulsions for which patents are common by the 1880s. Wolbers (1991b) gives an example of a typical recipe of the period that includes water, linseed oil, and, in lesser amounts, white spirit, caustic soda, copal, potato starch, casein, and manganese abietate.
Wolbers (1991a) found that the paint in both versions of The Last of the Buffalo stains positive for both oil and protein, indicating that casein or glue may have been present in the medium. It is possible that Bierstadt experimented with an emulsion paint in which the ingredients did not dry to form a satisfactory paint film, or in which a particular combination of ingredients caused deterioration. Explaining the myriad surface effects of some of these late paintings will require further research.
William MacLeod's entry for July 22, 1886, in the curator's journal of the Corcoran Gallery of Art (8:149) sheds some light on Bierstadt's use of surface coatings: “Mr. Bierstadt called.… He recommends going over his ‘Mt. Corcoran’ with ‘poppy oil’ & says the best varnish ever made is of copal dissolved in boiling turpentine. Weidenbach dissents from it.” Copal spirit varnishes made without oil were commercially available in England in the 19th century. In experiments with copal at the Canadian Conservation Institute, Carlyle (1998) has found that the spirit varnishes are similar in appearance to mastic and damar. Unlike these better-known resins, however, after a period of artificial light-aging the copal spirit varnishes continued to yellow significantly when placed in dark storage, but some reversal in yellowing did occur when they were again exposed to normal light conditions for only a few weeks. Moreover, removability of copal spirit varnishes has not been tested, and they may prove more intractable than mastic or damar films (Carlyle 1998). I have not found any evidence of copal varnish being used in the treatment of paintings in the Corcoran Gallery of Art. However, from the curator's journal and existing evidence it is clear that paintings were sometimes oiled.
It seems apparent that throughout the 1880s Bierstadt experimented with materials and techniques in a manner not evident in the more technically orthodox paintings of his heyday. Furthermore, his choice of materials during this period has sometimes had a deleterious effect on the appearance and condition of his paintings today. It seems likely that his experimentation with materials arose at least in part out of a concern for the preservation of his paintings, but in some cases the effect has been just the opposite.
I would like to thank the Scientific Research Department of the National Gallery of Art; Richard Wolbers; and the conservators, curators, and institutions who provided me with information and samples of graphite ground layers: Perry Huston, Helen Mar Parkin, Lance Mayer, Ross Merrill, Diane Kotowski, and the Rocky Mountain Regional Conservation Center. I am also indebted to Joyce Zucker, who first called to my attention the use of graphite paint on houses.
1. Diane Kotowski of the Department of Art, University of Denver, dates Weeping Oaks, Clear Creek, California, to 1880
National Gallery of Art, August 29, 1989 Science Department Analysis Report
Analysis of ground layers from five paintings
Material: oil paintings on canvas
Ground layers from five paintings by A. Bierstadt (table 1) were analyzed using light microscopy and powder x-ray diffraction spectroscopy. In each case, the black ground was found to be a mixture of graphite, a clay material (possibly montmorillonite), and iron oxides.
TABLE 1. GROUND LAYERS FROM FIVE PAINTINGS BY A. BIERSTADT
Samples from The Last of the Buffalo (Buffalo Bill Historical Center) and Rocky Mountain Sheep (private collection) were delivered to the department in the form of prepared cross sections. Each possessed intact grounds and image layers. Small pieces of tacking margins from the remaining paintings were submitted for analysis. Although these samples possessed intact ground layers, image layers were absent. Scrapings of the ground layers were taken using a scalpel. The ground samples were mounted as dispersions in Cargille Melt-Mount (nD = 1.662). Optical properties and particle morphologies were documented using polarized light microscopy.
Each of the five dispersions was found to consist of a mixture of three different components and/or particle types. Gray-black flakes or plates represented the predominant constituent. Although completely opaque, the gray-black flakes appeared to be coarsely crystalline and were compacted into numerous thin layers. Unmounted gray-black flakes were easily crushed with the tip of a stirring rod and left a dark smudge on the paper substrate. The flakes ranged from individual particles 2–3 μm in size to agglomerates 1–3 mm across. Optical and morphological properties exhibited by the unknown flakes are consistent with those for graphite (Gettens and Stout 1966; McCrone et al. 1979). X-ray powder diffraction spectroscopy yielded results consistent with JCPDS powder diffraction standards for graphite (e.g., JCPDS standard 13-0148 and 01-0640).
Light yellow-white through yellow-brown particles (size range = 1–114 μm) made up the second most abundant ground component. The particles were either isotropic or exhibited very low birefringence (nD = 1.662). Shape ranged from amorphous through angular, somewhat glassy fragments. Although Gettens and Stout (1966) state clay was frequently combined with graphite to serve as a binder, observable microscopic characteristics of the particles were insufficient for identifying the unknown as clay. Additionally, McCrone et al. (1979) states that clays are generally unidentifiable on microscopic bases alone. Therefore, powder x-ray diffraction (XRD) was chosen as an alternate analytical method.
Samples from two Bierstadt paintings were selected for analysis: 1. The Last of the Buffalo (Buffalo Bill Historical Center); and 2. Rocky Mountain Sheep. Results of the XRD analyses revealed the unknown to be montmorillonite. The identification was confirmed with a match to JCPDS standard 12–131. Montmorillonite is a member of the smectite group of clays. The basic chemical formula of the group is Al4Si8O20(OH)4 • nH20 (Deer et al. 1966). Chemical variation yields the clays in the smectite group. Montmorillonite has the formula (Na)0.7(Al3.3Mg0.7)Si8O20(OH)4 • nH2O.
The least abundant particle type in the ground layer samples was represented by highly birefringent (nD > 1.662) red through orange and yellow particles. These particles occurred in minor to trace amounts. Particle morphology was heterogeneous and varied from elongate and splintery through finely divided, somewhat opaque spherulites. Characteristics exhibited by the unknown particles are consistent with those for iron oxides and compared favorably to laboratory standards.
In conclusion, ground samples from the five Bierstadt paintings examined were composed of a mixture of graphite, clay, and iron oxides. The clay, for at least The Last of the Buffalo and Rocky Mountain Sheep, was demonstrated to be most closely allied to montmorillonite, a member of the smectite group of clays. For the remaining paintings, a more specific identity of the clay component was not assigned. It should be noted that Deer et al. (1966) describe smectite clays as being useful in the formulation of paints, paper, rubber, ceramics, and a variety of other materials.
Although the graphite ground (as it exists on the canvas support) appears to be discrete layer, it is noteworthy that the individual flakes/plates of graphite are arranged layer upon layer. Furthermore, these layers, as seen in cross section, are in varying states of adhesion to one another. It is difficult to determine how many applications were necessary to achieve the ground thickness observed.
Finally, the iron oxides present in the ground cannot necessarily be classified as an additive. Toch (1907) states that iron oxides, silica, or calcium carbonate were often added to graphite paint in order to provide a more suitable surface on which succeeding films could adhere. Gettens and Stout (1966), however, describe iron oxides as naturally occurring in clays. The reason for the presence of iron oxides in the grounds examined is unknown.
MICHAEL PALMER, Conservation Scientist RENE DE LA RIE, Head, Scientific Research Department
. A Leitz Orthoplan with Npl objectives was used. Several of the black particles were mounted in Cargille Melt-Mount (nD = 1.662) and examined at magnifications of 250× to 630×.Powder diffraction was carried out on all samples using a Phillips 3100 x-ray generator equipped with a copper anode and nickel target. Current settings were 45 kV and 25 mA. A 114-mm Gandolfi camera was used. Runtimes ranged from 5 to 12 hours in air.
Deer, W. A., R. A.Howie, and J.Zussman. 1966. An introduction to the rock-forming minerals. London: Longman Group.
Gettens, R. J., and G. L.Stout. 1966Painting materials: A short encyclopedia. New York: Dover Publications.
McCrone, W. C., J. G., Delly, and S. J.Palenik. 1979. The particle atlas, Vol. 5. 2d ed.AnnArbor, Mich.: Ann Arbor Science.
Toch, M.1907. The chemistry and technology of mixed paints. New York: D. Van Nostrand Company.
REFERENCESNote: All unpublished reports are available upon request from the author.
Berrie, B. H., and Palmer, M. R.1986. Analysis report/Bierstadt, A.The Last of the Buffalo/9.12 Corcoran Gallery. Corcoran Gallery of Art, Washington, D.C.
Berrie, B. H., and Palmer, M. R.1988a. Analysis report/Bierstadt, A./The Last of the Buffalo/Owner: Buffalo Bill Historical Center (Cody, WY). Corcoran Gallery of Art, Washington, D.C.
Berrie, B. H., and Palmer, M. R.1988b. Analysis report/Bierstadt, A./The Last of the Buffalo/9.12/Owner: Corcoran Gallery. Corcoran Gallery of Art, Washington, D.C.
Bierstadt, A.1877. Letter to William MacLeod [?], curator, June 27. Archives of the Corcoran Gallery and School of Art, Washington, D.C.
Carlyle. L. June 1998. Personal communication. Canadian Conservation Institute.
Hartwell, D. M., and H. M.Parkin. 1999. Corcoran and Cody: The two versions of The Last of the Buffalo, Journal of the American Institute for Conservation38: 45–54.
Hendricks, G.1988. Albert Bierstadt. New York: Harrison House.
Lomax, S. Q.1989. Analysis report/The Last of the Buffalo/Bierstadt/The Buffalo Bill Historical Center, Cody, WY/Analysis of media of ground sample. Corcoran Gallery of Art, Washington, D.C.
Mayer, Lance, and G.Myers. 1988. Examination report, Indian Sunset: Deer by a Lake. Yale University Art Gallery, New Haven, Conn.
MacLeod, W.1986. Curator's journal. Archives of the Corcoran Gallery and School of Art, Washington, D.C.
Palmer, M. R.1989. Analysis report/Bierstadt, A./Analysis of ground layers from five paintings. Corcoran Gallery of Art, Washington, D.C. This report is published in the appendix.
Parkin, H. M., and P. C.Huston. 1985. Treatment report for The Last of the Buffalo (Buffalo Bill Historical Center). Perry Huston & Associates, Inc., Fort Worth, Tex.
Warshaw Collection of Business Americana. Archives Center, National Museum of American History, Smithsonian Institution, Washington, D.C.
Wolbers, R. C.1991a. Analytical reports on samples from both versions of The Last of the Buffalo. Corcoran Gallery of Art, Washington, D.C.
Wolbers, R. C.1991b. Syllabus for Cleaning of paintings: A refresher course with Richard C. Wolbers, “Slides” section. University of Delaware, Newark, Del.
DARE MYERS HARTWELL has been the chief conservator at the Corcoran Gallery of Art, Washington, D.C., since 1983. She has a master's degree in art history from the University of Minnesota and received her conservation training at the Minneapolis Institute of Arts and the Institut Royal du Patrimoine Artistique, Brussels, Belgium. Her study in Brussels was funded by a Fellowships for Museum Professionals grant from the National Endowment for the Arts. She was previously the assistant painting conservator at the Upper Midwest Conservation Association in Minneapolis and the associate conservator at the North Carolina Museum of Art in Raleigh.