Partners and Projects

Science-Guided Conservation of a Miniature Diorama of a Kwakwaka'wakw Village

The miniature diorama of a Kwakwaka'wakw village in the American Museum of Natural History (AMNH M/135), before treatment © Objects Conservation Laboratory, Division of Anthropology, American Museum of Natural History

A renovation campaign of the Northwest Coast Hall at the American Museum of Natural History provided an opportunity to undertake the conservation of the large-scale Kwakwaka'wakw village model, continuously on view since 1896 and expected to remain part of the redesigned permanent exhibition. The village model had been previously repaired and additional components added; however, no written records document the date of these interventions, identification of added elements, or the materials used. Scientific analysis performed by the NICS team revealed the exact formulation of plasticine, used to form the human figures, and identified its degradation products in the form of sulfurous yellow crystalline efflorescence and soft brown extrusions consisting of wax and oils. This project aimed to call attention to plasticine’s poor aging characteristics and its likely occurrence in dioramas across anthropological collections.

Secrets of Decorated Objects from Eastern Siberia

Left to right: Birch bark container, AMNH Anthropology catalog # 70/663A; Reindeer hide apron, AMNH Anthropology catalog # 70/5602C; Gut skin parka, AMNH Anthropology catalog # 60/3585A. Courtesy of the Division of Anthropology, American Museum of Natural History, New York

A selection of artifacts from the Eastern Siberia collection of the American Museum of Natural History, formed in 1896 through 1902 as part of the Jesup North Pacific Expedition, was analyzed to support a conservation intervention. The materials that required characterization included a reindeer-hide apron with a red-painted decoration, a birch-bark container with black paint, and the pigments applied on a gut-skin parka. In all cases, scientific analysis was carried out with the main goal of documenting the materials and technology employed on these objects, which differed from the more usual means of decoration observed on other pieces in the museum's collection.

Blue Dyes in 19th- and 20th-Century Chinese Textiles

Left to right: Woman's dress, AMNH Anthropology catalog # 70/2341; Embroidered piece, AMNH Anthropology catalog # 70/4593A; Fabric, AMNH Anthropology catalog # 70/13433; Quilt, AMNH Anthropology catalog # 70.3/6506. Courtesy of the Division of Anthropology, American Museum of Natural History, New York

This project was initially inspired by anthropologist and historical geographer Berthold Laufer's textile collection acquired during his travel to China during 1901 through 1904. Originally focused on the use of natural blue-dye indigo—normally associated with ethnic minorities and southern mountainous areas—in the context of Han Chinese, the study has then developed into a broader investigation of both natural and synthetic blue dyes, aiming to gain insight into the advancement of the Chinese textile industry during the time Laufer visited China. Scientific analysis of a selection of Chinese textiles has helped determine which blue dyes were used by the Han Chinese population between the end of the nineteenth and early twentieth century, ultimately shedding light on the degree of progress of the Chinese textile industry overtime.

The Hidden Polychromy of Tsimshian Totem Poles

Left to right: Totem pole, AMNH Anthropology catalog # 16/565; Totem pole, AMNH Anthropology catalog # 16/566; Totem pole, AMNH Anthropology catalog # 16/567; Totem pole, AMNH Anthropology catalog # 16/568. Courtesy of the Division of Anthropology, American Museum of Natural History, New York

This project was undertaken in support of the conservation of a selection of Tsimshian totem poles located in the museum's Pacific Northwest Hall that have accumulated surface grime and darkened coating layers obscuring the underlying polychromy. Microscopic examination has determined the number of coating layers present and how they were intermixed with dirt and paint, while scientific analysis has offered insight about their chemical composition, thus informing the development of a proper removal method. While some of the colors could be successfully cleaned based on the information provided, the green paints' darkened coatings have proven difficult to remove. Thus, a second analytical campaign has aimed at identifying the pigments used in the green paints in order to understand their problematic character and anomalous behavior, in hopes of informing the optimization of a suitable cleaning treatment.

Materials Analysis and Radiocarbon Dating of an Olmec Mask

Olmec mask, AMNH Anthropology catalog # 30.2/9373. Courtesy of the Division of Anthropology, American Museum of Natural History, New York

An ancient Mexican mask of wood, culturally identified as Olmec and customarily dated between 1500 and 400 B.C., was purchased by the American Museum of Natural History from the Brummer Gallery shortly after the death of one of the Brummer brothers in 1947. Radiocarbon dating of this object was performed at the University of Arizona to determine its date with greater accuracy. Additional questions for scientific analysis that are relevant to the field of Olmec—and hence Mesoamerican—scholarship included the identification of the type of wood, the examination of the jade inclusions, and the analysis of color remnants observed in certain areas. Currently, the extant body of Olmec masks, made of various types of stone, is understood to be without additional coloring, so any evidence indicating that there was color on one might provide an opportunity to investigate other masks more carefully.

Mapping Original and Restoration Pigments in Blackburn’s Portrait of a Woman

Joseph Blackburn (American, active, ca. 1750-1780). Portrait of a Woman, ca. 1762. Oil on canvas, 44 x 35 13/16 in. (111.8 x 91 cm). Brooklyn Museum, 50.57; Dick S. Ramsay Fund

Joseph Blackburn's Portrait of a Woman is a splendid example of the artist's early/mid-career work. An English expatriate, Blackburn spent time in Bermuda and New England, painting prominent colonists before returning to the British Isles in his later years. Held by the Brooklyn Museum since 1950, Portrait of a Woman features a vase of tulips next to the sitter. One of the flowers, a variegated blossom in the center, has suffered extensively from pigment deterioration, overcleaning, and permissive restoration. The most recent conservation treatment has unearthed what little remains of Blackburn's original floral design, which was thought to contain arsenic-based pigments. Non-invasive analysis with a newly acquired mapping system shed light on the variety of coloring materials used in Blackburn's original floral design and subsequent restoration campaigns. This information will be used to accurately reconstruct the flower through retouching.

Egyptian Coffins Traveling the World

Left, Outer Sarcophagus of the Royal Prince, Count of Thebes, Pa-seba-khai-en-ipet, ca. 1075-945 B.C.E. Wood, gesso, pigment, 37 x 30 1/4 x 83 3/8 in., 287 lb. (94 x 76.8 x 211.8 cm, 130.2kg). Brooklyn Museum, Charles Edwin Wilbour Fund, 08.480.1a-b. Right, Scarab Coffin, 664–332 B.C.E. Wood, animal remains, 1 7/16 x 1 15/16 x 3 1/8 in. (3.6 x 5 x 8 cm). Brooklyn Museum, Charles Edwin Wilbour Fund, 37.1368Ea-c (Photo: Gavin Ashworth)

A coffin discovered in 1893 near Deir el-Bahari, Egypt, has been examined and treated in preparation for a loan from the Brooklyn Museum to the Korean National Museum. Scientific analysis of samples removed from this object was essential to addressing questions pertaining both to the history of the coffin and to its perplexing condition issue. A related project has focused on the characterization of a crystalline material that was found on the surface of an Egyptian scarab coffin after shipment to Seoul, Korea. The material was subjected to scientific analysis in order to determine whether it was related to packing materials or to the substance previously identified on the Brooklyn Museum coffin mentioned above.

Aiding the Conservation of an Egyptian Papyrus

Illustrated Book of the Dead of the Priest Herew, 360–200 B.C.E. Papyrus, ink, Large Box with Roll Inside: 5 13/16 x 7 11/16 x 30 1/16 in. (14.7 x 19.5 x 76.4 cm), "b" (large box with roll inside): 6 x 17 5/8 in. (15.2 x 44.8 cm). Brooklyn Museum, Charles Edwin Wilbour Fund, 37.1484Ea-b

The Brooklyn Museum holdings include a twenty-five-foot uncut Book of the Dead papyrus with a single smaller associated fragment. Both pieces—the long roll and the small fragment—were glued to a cotton support before arriving to the museum in 1937. The object had previously been at New York Historical Society (NYHS), coming from the Abbott Collection (a well-established nineteenth-century collection). It is unclear whether the cotton support was applied at Brooklyn Museum or at NYHS. Over time, the fabric support had buckled, and the papyrus was held unevenly and rather precariously on the support. The paper conservators at Brooklyn Museum had tried to determine whether the support could be removed and, if so, what the optimal procedure would have been. Scientific analysis of samples from the papyrus was carried out with the main goal to inform the development of a suitable treatment plan.

Infinite Blue Shades from 19th-Century Garments

Left to right: Dress, American, cotton, 1815-1820; 2009.300.7598. Dinner dress, British, silk and cotton, ca. 1820; 2009.300.3370. Wedding dress, American, silk and cotton, ca. 1860; 2009.300.923. Evening slippers, American, silk, ca. 1885; 2009.300.5753a,b. Stockings, American, silk, ca. 1890; 2009.300.7759a,b. Metropolitan Museum of Art, New York

Natural and synthetic blue dyes in nineteenth-century garments from The Met's Costume Institute were studied in support of the Brooklyn Museum's exhibition Infinite Blue, which took place between November 2016 and November 2017. The exhibition featured blue in all its variety, from ancient times to the present day, and included paintings, sculptures, prints, drawings, the decorative arts, illuminated manuscripts, printed books, and contemporary artworks from Asia, Africa, Egypt, the Americas, and Europe. Infinite Blue was part of A Year of Yes: Reimagining Feminism at the Brooklyn Museum, a yearlong series of ten exhibitions celebrating the tenth anniversary of the Elizabeth A. Sackler Center for Feminist Art.

Vibrant Color and Complex Technology of a Nasca Masterwork

Nazca Poncho or Tunic, 100-200 C.E. Camelid fiber, 74 7/16 x 27 9/16 in. (189.1 x 70 cm). Brooklyn Museum, Alfred W. Jenkins Fund, 34.1579

Scientific analysis of a Nasca textile masterwork belonging to the Brooklyn Museum was performed in support of an upcoming exhibition. In ancient times, such object was repurposed into a tunic, with embroidered neck slit and shoulder fringe. In addition to noninvasive examination, several samples were removed from the textile for micro-invasive analysis aiming to provide a complete characterization of the dyes used in this piece. Among all the colors identified, the anthraquinone dye madder was detected in all the red shades examined, except for the embroidery at the outer edges that, on the other hand, was found to have been dyed with cochineal. One additional fiber sample from the purple embroidery thread at the neck opening was then analyzed to verify the possible presence of a red dye different from madder, likely cochineal, which would support the hypothesis that such embroidery could be a later addition.

Materials and Techniques of Romano-Egyptian Funerary Portraits

Left to right: Mummy Portrait of a Man, ca. 120-130 C.E. Wood, encaustic, gold leaf, 17 1/4 x 7 3/4 x 1/16 in. (43.8 x 19.7 x 0.2 cm). Brooklyn Museum, Charles Edwin Wilbour Fund, 40.386. Mummy and Portrait of Demetrios, 95-100 C.E. Painted cloth, gold, human remains, wood, encaustic, gold leaf, 13 3/8 x 15 3/8 x 74 13/16 in., 130 lb. (34 x 39 x 190 cm, 58.97kg). Brooklyn Museum, Charles Edwin Wilbour Fund, 11.600. Brooklyn Painter (active Fayum, Egypt, A.D. 200-A.D.250). Boy with a Floral Garland in His Hair, ca. 200-230 C.E. Wood (European linden, lime), tempera, 11 3/4 x 7 13/16 x 3/8 in. (29.9 x 19.8 x 0.9 cm). Brooklyn Museum, Charles Edwin Wilbour Fund, 41.848. Noblewoman, ca. 150 C.E. Encaustic on wood, 17 5/16 x 11 5/16 x 1/8 in. (44 x 28.7 x 0.3 cm). Brooklyn Museum, Gift of the Ernest Erickson Foundation, Inc., 86.226.18

The Brooklyn Museum owns six Romano-Egyptian funerary portraits, four described as encaustic and two as tempera on panel. The museum's participation in the APPEAR Project, a Getty-supported initiative, has provided an impetus for the thorough documentation and analysis of all six portraits, with the goal of developing a clear understanding of the original painting materials and techniques, as well as distinguishing areas of restoration. The study initially aimed at investigating the presence of indigo in the portraits based on the preliminary examination of series of historically accurate paint-outs through multiband imaging techniques; the response obtained in areas thought to contain such blue colorant was then verified with noninvasive equipment and in series of samples. In addition, further analysis with complementary instrumental tools aimed at ascertaining the nature of the binding media in the portraits.

Study of the Cracking System of a Khaemhat Statue

Fragmentary Kneeling Stelephorus Statue of Khaemhat, front, side and back views, ca. 1539–1075 B.C. Granite, 18 1/2 x 9 1/8 x 10 13/16 in. (47 x 23.2 x 27.5 cm). Brooklyn Museum, Charles Edwin Wilbour Fund, 37.48E

The Egyptian stone sculpture Fragmentary Kneeling Stelephorus Statue of Khaemhat, belonging to the collection of the Brooklyn Museum, is being prepared for an upcoming exhibition and loan focusing on iconoclasm and intentionally damaged Egyptian sculpture. This sculpture shows extensive, deep, and blind cracking throughout the structure, which appears to radiate from the center of the stone outward. Based on ancient records reporting on the destruction of sculptures by fire, it has been hypothesized that this piece might have suffered such damage from heating. The literature indicates that sculptures with similar cracking either have high content of iron-rich minerals that oxidize and expand causing cracking or have been subjected to high heat. Scientific analysis aimed to determine the type of stone, the cause of the cracking, and to characterize the brown accretions found on the surface of the statue.

Assisting the Cleaning of J. Q. A. Ward's 7th Regiment Memorial

Right: John Quincy Adams Ward (1830-1910). 7th Regiment Memorial, 1869. The Central Park Conservancy, New York.

As part of the cyclical preservation maintenance of its collection of more than fifty outdoor bronze sculptures, the Central Park Conservancy has recently undertaken the conservation of the Seventh Regiment Memorial (1869) by J. Q. A. Ward. The treatment consisted of lacquer-coating removal and refurbishment, and the new coating is a two-part system shown to increase corrosion resistance while maintaining the appropriate aesthetic. Various other actions, such as bronze surface stabilization, securing the gunstock, and integrating a stone "Dutchman" repair on the granite base, were also completed. Samples of coating residue, bronze filings, and corrosion products were collected from inside and outside the figure and analyzed to guide the treatment and help to fill in the blanks of incomplete historic documentation.

Supporting the Conservation of P. Manship's Lehman Gate

Paul Manship (1885-1966). Lehman Gate, 1961. The Central Park Conservancy, New York

Lehman Gate, aka Boy with Goats (1961), stands above the entryway of the Children's Zoo in Central Park and memorializes the fiftieth anniversary of Governor H. Lehman and his wife. Because of very challenging site conditions, the bronze sculpture was temporarily removed for treatment at a park facility. Its conservation plan included the removal of many layers of deteriorated coating, welding repairs, and application of a new coating system, culminating with the work's reinstallation in May 2018. In light of this, several samples were collected to help inform the treatment procedure by identifying specific constituents of the metallic alloy, degradation products, organic coatings, and investment materials. The analytical findings aided with the approach for mitigating corrosion and welding methodology, and permitted a more accurate assessment of the founding of the sculpture and past treatment history.

Guiding the Treatment of B. Pickett's Samuel Morse

Left: Byron M. Pickett (ca. 1834–1907). Samuel F. B. Morse, 1871. The Central Park Conservancy, New York

A collaborative project proposed by the Central Park Conservancy sought to support the conservation of the Samuel F. B. Morse statue, created in 1870 by Byron Pickett and located at Fifth Avenue and 72nd Street entrance to the Park Drive. A first phase of this long-term project, carried out in the summer of 2018, aimed at characterizing the degradation products that are heavily affecting some portions of the surface and the organic coatings that protect the bronze. More recently, a second phase was devoted to monitoring and supporting the laser cleaning treatment using non-invasive techniques, with a special focus on the detection of variations in the levels of sulfur and chlorine as markers of the degree of degradation. The additional examination of a cross section revealed that the main copper/tin/zinc ternary alloy, constituting the bulk of the sculpture, is covered by several corrosion layers containing cuprite and copper sulfates.

Our current collaboration with the Cooper Hewitt Smithsonian Design Museum is on hold due to the COVID-19 pandemic. We look forward to sharing project descriptions and images when available.

Materials Analysis of Koegler's Unidentified Man Medallion

Mathias Koegler (?). Unknown Man, front and back views, 1778 or later. Stone, frame in gilt copper alloy, diam. 3 1/8 in. (7.92 cm). The Frick Collection, 2016.2.214; gift of Stephen K. and Janie Woo Scher, 2016. © The Frick Collection

A medal in the Frick Collection titled Unidentified Man (1778), possibly by Mathias Koegler, was analyzed in support of the exhibition The Pursuit of Immortality: Masterpieces from the Scher Collection of Portrait Medals (May 9 through September 10, 2017). This medal, thought to be made of a glass paste, was described in a publication on the Scottish gem engraver and modeler James Tassie (1735–99) as "made of a paste which simulates marble most effectively but is quite unlike any glass used by Tassie. Extensive research so far has not shed any light on who Koegler was, nor has the gentleman been recognized." A combination of microscopic examination and scientific analysis ruled out the use of a vitreous substance, and indicated that the medal is made of a naturally formed gypsum rock, such as a fine-grained alabaster.

The Origin of Three Italian Renaissance Marble Busts

Left, Francesco Laurana (ca. 1430-ca. 1502). Bust of a Lady, ca. 1470s. Marble, 18 3/8 x 18 x 9 3/8 in. (46.7 x 45.7 x 23.8 cm). The Frick Collection, 1916.2.01; Henry Clay Frick Bequest. Center, Francesco Laurana (ca. 1430-ca. 1502). Beatrice of Aragon, 1471-74. White marble, 16 x 15 7/8 x 8 in. (40.6 x 40.3 x 20.3 cm). The Frick Collection, 1961.2.86; bequest of John D. Rockefeller, Jr., 1961. Right, Andrea del Verrocchio (1435-1488).Bust of a Young Woman, 15th century. White marble, 18 5/8 x 19 3/16 x 9 3/8 in. (47.3 x 48.7 x 23.8 cm). The Frick Collection, 1961.2.87; bequest of John D. Rockefeller, Jr., 1961. © The Frick Collection

Three important fifteenth-century Italian Renaissance marble busts—namely Bust of a Young Woman by Andrea del Verrocchio and Francesco Laurana's Beatrice of Aragon and Bust of a Lady—were analyzed in an attempt to authenticate the latter, whose attribution and date have been called into question, and to identify the marble used and corresponding quarries for the three objects. Results will be compared with those obtained from similar fifteenth-century Italian busts in other institutions, such as the Circle of Verrocchio's A Lady and Laurana's A Princess of the House of Aragon, from the National Gallery of Art, Washington, D.C.

A Technical Study of Bertoldo di Giovanni's Shield Bearer

Right: Bertoldo di Giovanni (1420/1430–1491). Shield Bearer, early 1470s. Copper alloy, with extensive traces of gilding, 8 13/16 × 3 3/4 × 2 3/4 in. (22.4 × 9.5 × 7 cm). The Frick Collection, 1916.2.03; Henry Clay Frick Bequest. © The Frick Collection

In his early years a disciple of Donatello, Bertoldo di Giovanni helped to develop the art form of the bronze statuette during the Italian Renaissance, and was a sculptor and medal-worker at the court of Lorenzo the Magnificent in Florence. An upcoming exhibition at the Frick Collection that focuses on Bertoldo's Shield Bearer has provided an opportunity to carry out an in-depth technical study of this object in relation to similar ones in other institutions. Scientific analysis aimed at investigating the gilding, the corrosion products, the organic coatings, as well as the composition of the metal alloy and solder in original and restored portions of the bronze statuette.

Lacquered artifacts from the viceregal Colombia

Left: Portable writing desk (interior of the lid). Pasto, Colombia, ca. 1684. Barniz de Pasto lacquer on wood, H 19 × W 36 × D 30.5 cm, LS2000. Top right: Casket. Pasto, Colombia, 1625-1650. Barniz de Pasto lacquer, H 15 x W 18 x D 8.6 cm, LS2361. Bottom right: Coffer. Pasto, Colombia, ca. 1650. Barniz de Pasto lacquer on wood with silver and gold leaf and silver mounts, H 19.2 x L 26 x W 12.3 cm (L with feet 27.2 cm; W with feet 13.7 cm), LS2067. Courtesy of The Hispanic Society of America.

The Hispanic Society of America owns a small group of South American viceregal lacquers, largely acquired in the last three decades, which were created by indigenous artisans for a European aesthetic and meant to imitate Asian lacquers. Among them, a lacquered gourd made in Pasto (LS2400) has already been object of an in-depth scientific study. Following the outstanding findings on the gourd, the research has been expanded to other objects decorated using Barniz de Pasto in the seventeenth-century. The main goal is to determine pigments and dyes used to color the resin, establishing a timeline in their use through scientific analyses. Of particular interest will be the investigation of the use of cochineal as red dye, already reported on the gourd, as well as of calomel and lead white used as white pigments.

In Search of the Colors of a Colonial Spanish-American Lacquered Gourd

Gourd Vase (Barniz de Pasto). Pasto, Colombia, 17th century. Lacquer, Barniz de Pasto, H 12 cm, LS2400. Courtesy of The Hispanic Society of America, New York

The Hispanic Society of America owns a small group of South American colonial lacquers in its collection made by indigenous artisans for a European aesthetic and meant to imitate Asian lacquers. Among these is a gourd made in Pasto, Colombia, in the seventeenth century. This object is decorated with barniz de Pasto, an indigenous technique that uses local, raw materials including natural dyes, silver leaf, and a resin extracted from a plant native to tropical rainforests in the upper Andes and commonly known as mopa mopa. Scientific analysis enabled the NICS team to confirm the identity of the resin and compare the variety of dyes and pigments found in this object to those listed by von Humboldt, German naturalist and explorer who travelled through the region in 1801. Radiocarbon dating was also performed at the University of Arizona to correlate the exact date with details of the decorative motifs and fabrication technique.

Fingerprinting Luisa Roldán's Terracotta Works

Luisa Roldán (1652–1704). Left, The Repose in Egypt, ca. 1690. Terracotta group, polychrome, 16 1/8 × 18 1/8 × 12 in. (41 × 46 × 30.5 cm), D821. Right, The Ecstasy of Saint Mary Magdalene, ca. 1690. Terracotta group, polychrome, 12 × 17 1/2 × 9 7/8 in. (30.5 × 44.5 × 25.1 cm), D822. Courtesy of The Hispanic Society of America, New York

The Hispanic Society of America owns three important terracotta groups by Luisa Roldán (1656–1704): The Mystical Marriage of Saint Catherine, The Repose in Egypt, and The Ecstasy of Saint Mary Magdalene. In addition, two terracotta heads—The Head of St. John the Baptist and The Head of St. Paul, which also entered the collection in 1912 as part of the same purchase—have been recently attributed to Roldán. These sculptures had suffered several campaigns of overpainting, making the polychrome surface flat and deadening the movement of the sculpted figures. A selection of samples removed from unadulterated sites of the three terracotta groups has been examined to ascertain the composition of the clay and identify the pigments used by the artist. This data were compared with those collected from the two attributed heads in the Hispanic Society collection and The Met's own Roldán terracotta.

A Technical Study of Black Book of Hours Across Collections

Horae Beatae Mariae secundum usum curie romane [Black Book of Hours], Spain (?), ca. 1458. Black tinted parchment with gold and silver illumination, H 14.7 x W 10.1 cm, B251. Provenance: María of Castile, queen of Alfonso V of Aragón; Bishop Juan de Palafox y Mendoza. Courtesy of The Hispanic Society of America, New York

One of the rarest items in the Hispanic Society's manuscript collection is a Black Book of Hours on vellum stained with black ink or painted with black pigment. This manuscript is unfinished in that the artist left space on the pages facing the beginning of each office for a miniature. The calendar is appropriate for the Crown of Aragon, with the canonization of St. Vincent Ferrer in 1455 as the earliest possible date of composition of the manuscript. Possibly related to another Black Book of Hours in the Morgan Library collection previously analyzed by NICS scientists, this manuscript was subjected to scientific analysis to determine whether such relationship subsists, through assessment of the existing similarities in terms of chemical composition of the inks used for the lettering and decorations, as well as the artist's palette.

The Visconti-Sforza Tarot Cards and the Prayer Book of Michelino da Besozzo: unravelling the secrets of Milanese illumination in the early to mid-fifteenth century

Left to right: MS M. 944, fol. 11v; MS M. 630.1, The Juggler; MS M. 630.5, Temperance; MS M. 630.4, The Pope; MS M. 630.35, The Ten of Swords. Courtesy of The Morgan Library & Museum.

The Visconti-Sforza Tarot Deck is a rare example of playing cards dating back to the mid-fifteenth-century. The deck, originally composed of 78 cards, was commissioned as a wedding gift for Francesco Sforza and Bianca Maria Visconti, in 1441. The Morgan Library & Museum holds 35 of the extant 74 playing cards attributed to Bonifacio Bembo and two additional artists circa 1450. The cards are illuminated with figural representations as well as decorated pip cards. Sixteen cards have been examined with an array of non-invasive and micro-invasive techniques, for evidence of manufacture, exploring the nature of pigments and binders used, the type of metal used for the illumination, and the method of application. Additionally, the Prayer Book of Michelino da Besozzo, a masterpiece of the early-fifteenth-century Lombard illumination written and illuminated in Milan in ca. 1430, has been included in the study, due to its potentially direct impact on the style, technique, and materials used by Bonifacio Bembo on the tarot cards.

This study, conducted in collaboration also with Yale University's Beinecke Rare Book and Manuscript Library, the Yale Library Center for Preservation and Conservation, and Yale’s Institute for the Preservation of Cultural Heritage, will add significantly to the understanding of Milanese illumination in the early to mid-fifteenth century.

Color, Collation, and Curious Creatures in 15th-Century Block Books

The Morgan Library & Museum, left to right: PML 8 fol. 43v, PML 3 fol. 12b, and PML 10 fol. 4v. Purchased with the Bennett collection, 1902. Photographic credit: The Morgan Library & Museum, New York

The Morgan Library & Museum owns the largest collection of block books in North America, most of which are attributed to the Netherlands and Germany and dated to ca. 1460–1480. Block books are multi-page works produced entirely from hand-colored woodcuts, with both text and image carved in relief in a single block. Although created for only a few decades in the late fifteenth century, block books represent a parallel production method, as the invention of typographic printing was introduced and quickly dominated the book market. As little is known about the composition of early printing inks and, more broadly, of the materials constituting the block books, scientific analysis has focused on the identification of the brown and black inks, as well as the range of mineral pigments and natural dyes used in these objects. In the future, the work performed thus far may be expanded to include block books from other institutions in the NICS program.

Royal Purple and Burgundian Black in Medieval and Renaissance Illuminated Manuscripts

The Morgan Library & Museum, left to right: MS M.23, fol. 38V, photography by Maria Fredericks; MS M.495, fol. 50V, photography by Frank Trujillo; MS M.319, fol. 10V, photography by Frank Trujillo; MS M.493, fol. 57R, photography by Frank Trujillo

The Morgan Library holdings includes series of medieval illuminated manuscripts that have had questions raised regarding their manufacture. This collaborative study focused on two main body of works: purple and black manuscripts. Scientific analysis by means of noninvasive techniques has provided preliminary information on the type of natural colorants possibly used to dye or paint the purple folios, as well as on the composition of the metallic inks and pigments found in the most relevant illuminations. Micro-invasive investigations were also performed to answer outstanding questions on dye and pigment identification and their degree of fading. Examination of the black manuscripts aimed to determine the chemical composition of the black coating. Additional analyses have addressed the identification of binding media in a selection of illuminations from both groups.

Tracing the Restoration of an 11th-Century Illuminated Manuscript

The Morgan Library & Museum, MS M.651, left to right: fol. 8V; fol. 127R; fol. 1V. Photography by Frank Trujillo

Preliminary studies of the pigments used in a deluxe eleventh-century gospel book from Cologne, Germany—now in the Morgan Library—had revealed the presence of a cobalt-containing pigment, likely cobalt blue (first synthesized in 1802), suggesting a possible retouching of the four main miniatures. Because this manuscript is such a rare and relevant example from a particularly rich period in the history of painting in Cologne (only two comparable manuscripts have survived), a more in-depth scientific study aimed to shed light on the nature and scope of any retouching that may have occurred. Results showed the presence of several traditional pigments, but no cobalt blue; however, scientific analysis found cobalt yellow—a brilliant, transparent yellow pigment, commonly known by the name aureolin, that was introduced as an artists' pigment in 1852 and that was thus added to the miniatures at a later date.

Study of Original and Restoration Materials in Coptic Manuscripts

The Morgan Library & Museum, left to right: MS M.574, fol. 1V; MS M.567, fol. 1V; MS M.567, fol. 2R; MS M.588, fol. 8V. Photography by Maria Fredericks

A collaborative project on the analysis of Coptic manuscripts from the Morgan Library collection was undertaken in preparation for a symposium coinciding with an exhibition about bookbinding and related craft and decorative traditions from Late Antiquity. Among the topics discussed was the history of conservation treatments applied to the museum's late Coptic manuscripts, from the Fayoum region of Egypt and dated mostly to the ninth through tenth century, and their bindings. Shortly after being excavated in 1911, the manuscripts were sent to the Vatican for restoration, and a hypothesis was put forward that losses to some leaves may have been filled with cast gelatin hardened with formalin. Scientific analysis shed light on the variety of inks and pigments, as well as the exact chemical composition of the fill material—that is now brittle and beginning to shatter—in order to guide future conservation treatments.

Thomas Gainsborough's Experimental Drawing Techniques

Thomas Gainsborough, (1727–1788). Left, Hilly Landscape with Cows on the Road, The Morgan Library & Museum, III, 62. Center, Study of a Lady, The Morgan Library & Museum, III, 63b. Right, A Woman and Three Children, The Morgan Library & Museum, III, 59. Photography by Steven H. Crossot, 2014

Celebrated in his lifetime as an outstanding draftsman and renowned painter of portrait and rural landscapes, Thomas Gainsborough (1727–88) remains a central figure in the history of British art and, more generally, of eighteenth-century art. An in-depth examination and technical study of his twenty-five drawings owned by the Morgan Library was performed in preparation for the exhibition Thomas Gainsborough: Experiments in Drawing (May 11 through August 19, 2018) and related catalogue. The show narrates Gainsborough's artistic journey in a powerful sequence of drawings and offers an exploration of his work as a draftsman, with a closer look at his technical innovations, his mastery of materials, and his development of a new and original approach to drawing. In this context, scientific analysis has focused on the identification of white pigments, binding media, and varnishes used by the experimental British artist.

Gouache Colorants and Pigments Used by Henri Matisse

Left, Henry Matisse (1869-1954). Maquettes for a set of red and yellow liturgical vestments, ca. 1950. Gouache on cut-and-pasted paper, mounted on paper. Museum of Modern Art, New York, 176.1953.5; acquired through the Lillie P. Bliss Bequest (by exchange) © 2018 Succession H. Matisse / Artists Rights Society (ARS), New York. Right, study set of painted paper samples, ca. 1947–54. Gouache on paper, seventy-nine pieces. Gift of the Matisse family, 2014 © MoMA

In the last two decades of his career, Henry Matisse started using cut paper and colorful gouaches as his primary medium. In the fall of 2014, MoMA organized Henry Matisse: The Cut-Outs (October 12, 2014, through February 8, 2015), the most comprehensive exhibition ever devoted to this innovative body of work. The exhibition included a set of seventy-nine samples of painted paper cutouts that were discarded by Matisse and donated to MoMA by the artist's heirs, providing a unique opportunity to study and thoroughly characterize his colored gouaches. In addition to providing valuable information on the range of painting materials used by Matisse, a full characterization of the colorants and pigments in his gouache paper samples was crucial to inform the development of proper conservation treatments and preservation strategies that may prevent or minimize light-induced damage.

Photographic Technique and Color Retouches in the Arctic Exploration Album

Dog-Team Under Way with Sail, without (left) and with (right) retouching, from Arctic Exploration, MFY+ 96- 4073. The Miriam and Ira D. Wallach Division of Art, Prints and Photographs, Photography Collection. The New York Public Library, Astor, Lenox and Tilden Foundations

A project proposed by the New York Public Library involved the technical analysis of a selection of photographs from a group of 157 made during the 1894-1897 Jackson-Harmsworth expedition to Franz Josef Land. In the early twentieth century, the library assembled photographs from various Arctic expeditions, including the Jackson-Harmsworth, into one scrapbook. Gifted from publishing houses, the photographs are heavily re-worked with overpainting, masking, as well as drawn and collaged elements. As ephemeral transitional objects, intermediate phases between negative and book illustration, it is unusual that these edited photographs survived to the present. Scientific analysis was requested to evaluate the extent of color retouching and to verify the presence of silver halides within any of the prints, which would have supported the hypothesis that some of them may have been printed on-site, in the Arctic, and incompletely processed. 

Elizabeth Buehrmann's Photographic Process

Left to right: Julie Hudak, 1912; Edith Emerson, 1904-1921; Paul Haviland and Maurice de Zayas, 1914; Mrs. Herman Atkins MacNeil, 1906-1908. The New York Public Library Digital Collections. The Miriam and Ira D. Wallach Division of Art, Prints and Photographs: Photography Collection, The New York Public Library

The New York Public Library holds a significant amount of photographic prints by American photographer Elizabeth Buehrmann (ca. 1886–1963). A collaborative study on a selection of twenty-six photographs has been performed in support of their conservation treatment and curatorial research on Buehrmann and her work that was presented in October 2017 at Princeton University's symposium Rethinking "Pictorialism": American Art and Photography from 1895 to 1925. Noninvasive scientific analysis with X-ray-based instrumental techniques shed light on the photographic process used by the artist in these prints, which were identified as silver prints over a baryta layer or platinum prints. This study has also allowed the conservation and curatorial team to correct the process identification cataloging records for the entire collection of Buehrmann prints of the New York Public Library and The Met.

Materials Analysis and Preservation of Monumentos Guadalupanos

Left, Spencer Collection, The New York Public Library, Oceletepec, Santa Maria, 1700-1750, The New York Public Library Digital Collections. Center and right, Manuscripts and Archives Division, The New York Public Library, Nican Mopohua, 1500-1600, The New York Public Library Digital Collections

Another project proposed by the New York Public Library has entailed the scientific analysis of the Nican Mopohua—a beautiful example of classical poem in Nahuatl language and one of the treasures of the museum's collection of American Indian literature—and a Mexican codex. The first manuscript belongs to a set of documents known as the Monumentos Guadalupanos, or Guadalupan Monuments, related to the worship of the Virgin of Guadalupe and her apparitions there. Noninvasive examination of the objects and micro-invasive analysis of samples has aimed to provide an in-depth characterization of the manuscripts' inks, pigments, and colorants in order to shed light on the variety of materials used, propose a range of possible dates, and inform future preservation strategies.

Addressing the Conservation of Two Paintings by Georges Braque

Georges Braque (1882-1963). Left, Piano and Mandola (Piano et mandore), winter 1909–10. Oil on canvas, 36 1/8 x 16 7/8 inches (91.7 x 42.8 cm). Solomon R. Guggenheim Museum, New York, 54.1411. Right, Violin and Palette (Violon et palette), September 1, 1909. Oil on canvas, 36 1/8 x 16 7/8 inches (91.7 x 42.8 cm). Solomon R. Guggenheim Museum, New York, 54.1412

Collaborative work with the Solomon R. Guggenheim Museum includes a study of Georges Braque’s Piano and Mandola (1909-1910) and Violin and Palette (1909), both significant examples of analytical Cubist works that typify Braque's revolutionary approach to painting, characterized by multiple viewpoints and fragmented forms. A previous treatment, which impregnated the fine linen support and absorbent ground, caused the space to appear much flatter and homogenous than originally intended. In addition, wax residues render the surface inappropriately glossy. Scientific analysis has shed light on the color palette, on the identity of the wax used for lining, and on the stratigraphy of the paint in areas of the works that are thought to include possible surface coatings. These results inform the rigorous process of designing a treatment strategy to regain the surface without compromising the fragile structure of the paintings. Funding for the conservation of these artworks was generously provided through a grant from the Bank of America Art Conservation Project.

Revealing Édouard Manet's Hand in Woman

Right: Édouard Manet (1832-1883). Woman (Femme), ca. 1877–80. Oil on canvas, 68 5/8 x 32 7/8 inches (174.3 x 83.5 cm). Solomon R. Guggenheim Museum, New York, 78.2514.28; Thannhauser Collection, gift, Justin K. Thannhauser, 1978

A scientific study of Édouard Manet's Woman in Striped Dress (1877–80) has given conservators deeper insight into the artist's materials, techniques, and artistic process. This painting has had a severely discolored varnish applied on the surface that obscured the lively brushwork, shifted the colorful palette, and distorted the work's spatial relationships. Also, historical photographs indicate that the picture was cut down and looked significantly different in Manet's studio right after his death. Scientific analysis of a sample removed from the painting surface has provided information on the chemical composition of the varnish, thus informing the optimization of a treatment plan suitable for its removal. In addition, examination of several cross sections taken from various areas of the artwork has shed light on the painting materials used, as well as on the extent and exact location of the later reworking.

Fading Colors and Altered Surfaces in Three Vincent van Gogh Paintings

Vincent van Gogh, (1853-1890). Left, Roadway with Underpass (Le viaduct), 1887. Oil on cardboard, mounted on panel, 12 7/8 x 16 1/8 in. (32.7 x 41 cm). Solomon R. Guggenheim Museum, New York, 78.2514.17; Thannhauser Collection, gift, Justin K. Thannhauser, 1978. Center, Landscape with Snow (Paysage enneigé), February/March 1888. Oil on canvas, 15 1/16 x 18 3/16 in. (38.2 x 46.2 cm). Solomon R. Guggenheim Museum, New York, 84.3239; Thannhauser Collection, gift, Hilde Thannhauser, 1984. Right, Mountains at Saint-Rémy (Montagnes à Saint-Rémy), July 1889. Oil on canvas, 28 1/4 x 35 3/4 in. (71.8 x 90.8 cm). Solomon R. Guggenheim Museum, New York, 78.2514.24; Thannhauser Collection, gift, Justin K. Thannhauser, 1978

The subject of this study is three works by Vincent van Gogh, namely Roadway with Underpass (1887), Landscape with Snow (1888), and Mountains at Saint-Rémy (1889), all of which exhibit some degree of color alteration. Moreover, the earliest painting has a thick, discolored varnish that covers a brown layer, both applied during an early restoration, resulting in a disfiguring appearance, obscured spatial and color relationships, and abraded areas from an earlier cleaning. Due to this unusual and compromised appearance, questions arose regarding authenticity. Scientific analysis determined the type and distribution of materials used in these works, indicating that both the brushwork and artist's palette of all three paintings are consistent with other van Gogh works. Most notably, an eosin-based lake (a pigment historically sold as Geranium Lake) has been detected in areas that display severe fading.

History of Repainting Alexander Calder's Motorized Sculptures

Alexander Calder (1898-1976). Half-circle, Quarter-circle, and Sphere, front and back views, 1932. Painted metal and wood with motor, 76 5/8 × 35 1/2 × 25 in. (194.6 × 90.2 × 63.5 cm). Whitney Museum of American Art, New York, 69.258; purchase, with funds from the Howard and Jean Lipman Foundation, Inc. 2018 © Calder Foundation, New York / Artists Rights Society (ARS), N.Y.

The Whitney Museum of American Art owns one of the largest motorized works made by renowned American artist Alexander Calder, titled Half-circle, Quarter-circle, and Sphere (1932). This mobile sculpture, featured in the exhibition Calder: Hypermobility (June 9 through October 23, 2017), displayed several issues, including the application of multiple repainting layers. Scientific analysis provided insight into the stratigraphy of Calder's painted surfaces, revealing in some cases the presence of materials that were available in the early 1930s, which supports the hypothesis that a layer of original paint may be present in certain areas of the work. In addition to enabling conservators to comprehend and restore the object's original appearance and kinetic motion, this study informed the optimization of a treatment plan tailored for the safe removal of the overpaint to uncover the original layer, wherever present.

Carmen Herrera and Solvent-Based Acrylic Paints in Post-War Europe

Carmen Herrera (born 1915). Left to right: Untitled, 1948. Acrylic on canvas, 48 × 38 in. (121.9 × 96.5 cm). Collection of Yolanda Santos. Photograph by Roberto Ortiz. Siete, 1949. Acrylic on canvas, 46 × 30 in. (116.8 × 76.2 cm). Collection of Paul and Trudy Cejas. Iberic, 1949. Acrylic on canvas on board, diameter: 40 in. (101.6 cm). Courtesy the artist and Lisson Gallery. © Carmen Herrera

The Whitney Museum recently hosted a partial retrospective of the Cuban-American 103-year-old female artist Carmen Herrera titled Carmen Herrera: Lines of Sight (September 16, 2016, through January 9, 2017). On this occasion, it was noted that the artist had listed the binding media for all the paintings in the exhibit as acrylic even though the earliest works dated from the late 1940s to early 1950s, when Herrera was in Paris and acrylics were not yet known to be commercially available in Europe. Questioned about the unexpected media assignments, Herrera recalled buying early acrylic paints in an art supply store near her studio in the French capital. Scientific analysis of a selection of Herrera paintings dated from 1948 to 1952 offered insight on Herrera's painting materials and uncovered a complex progression of organic binders, shedding new light on the history of availability and use of acrylic-based artist's paints in Europe.

Materials Analysis and the Conservation of Plastic Artworks

Left, Jeff Koons (b. 1955). New Hoover Convertibles, Green, Blue; New Hoover Convertibles, Green, Blue; Doubledecker, 1981-1987. Four vacuum cleaners, acrylic, and fluorescent lights, overall: 116 × 41 × 28in. (294.6 × 104.1 × 71.1 cm). Whitney Museum of American Art, New York, 89.30a-k; purchase, with funds from The Sondra and Charles Gilman, Jr. Foundation, Inc., and the Painting and Sculpture Committee © Jeff Koons. Top right, Matthew Barney (b. 1967). Cremaster 3: Hiram Abiff, 2002. Chromogenic print in self-lubricating plastic frame, Overall (framed): 53 1/2 × 43 1/2 × 3/4in. (135.9 × 110.5 × 1.9 cm); Sheet (sight): 49 1/2 × 39 1/2in. (125.7 × 100.3 cm); Image (sight): 49 1/2 × 39 1/2in. (125.7 × 100.3 cm). Whitney Museum of American Art, New York, 2005.149a-b; gift of Dean Valentine and Amy Adelson © Matthew Barney; courtesy Gladstone Gallery, New York. Bottom right, Matthew Barney (b. 1967).  CR 4: Loughton Ram, 1994. Chromogenic print in self-lubricating plastic frame, Overall (framed): 33 1/4 × 23 1/2 × 1 1/4in. (84.5 × 59.7 × 3.2 cm); Sheet (sight): 29 1/4 × 19 1/4in. (74.3 × 48.9 cm); Image (sight): 29 1/4 × 19 1/4in. (74.3 × 48.9 cm). Whitney Museum of American Art, New York, 2007.99a-b; gift of Linda and Ronald F. Daitz in honor of Adam Weinberg © Matthew Barney; courtesy Gladstone Gallery, New York

A collaborative effort with the Whitney Museum entailed the characterization of plastics in selected artworks from the museum's holdings, aiming to confirm plastic types, monitor aging and degradation, update storage needs, and inform future treatment and display parameters for the objects under examination. This project involved in-depth scientific analysis of specific series of plastics-containing works that are represented in multiple regional museums and have well documented fabrication dates. To date, noninvasive analysis of Jeff Koons's New Hoover Convertibles, Green, Blue; New Hoover Convertibles, Green, Blue; Doubledecker (1981–87) identified various types of plastics, as well as pigments, colorants, and fillers. In addition, the examination of samples removed from four objects by Matthew Barney provided information on the materials constituting the frames and backing boards.