Seeking Balance: Material and Meaning in a Polychrome Guanyin

The Cloak of Decay

Seated with one leg hanging pendant and the other bent at waist level, an arm draped casually over the knee, the Guanyin at the Art Institute of Chicago (fig. 1; see also its object page) is one of several large, carved in the round, polychrome wood sculptures thought to represent either the Water-Moon Guanyin (Shuiyue Guanyin, 水月觀音) or the Guanyin of the Southern Seas (Nanhai Guanyin, 南海觀音; see, for example, figs. 2–6).^[1] Both are distinctly Chinese manifestations of the bodhisattva of compassion known in India as Avalokiteśvara, and they are frequently depicted in painting and sculpture in the pose of “royal ease.”^[2] The cult of Guanyin (“perceiver of sounds”) became popular in China during the tenth century, coinciding with the establishment of the pilgrimage site Putuo Island, which was believed to be the location of the mythical mountain Potalaka (Putuoluojia, 普陀洛迦) that is mentioned in the Avatamsaka Sutra as the home of Guanyin.^[3]1

Figs. 2–6

Some comparable sculptures in western collections of the Nanhai Guanyin with significant surviving polychromy.

Before undergoing conservation in 2017, the Chicago Guanyin appeared as if strangely frozen in transition. Half of its face was dingy, gray, and cracking, and the other half was white with scattered bright red spots (see fig. 7). The proper right arm and hand, extending elegantly into the viewer’s space, had similarly uncohesive surfaces: a bright white finger and arm emerged from a gray shoulder and a reddish torso. And yet the figure’s rich gilded drapery attested to better times. The sculpture still exerted power through its dynamic form, but with its disrupted paint surface presenting a muddled appearance, damage and decay had become the dominant subject matter.2

Archival photographs from thirty years prior indicate that the sculpture once looked much different. Cloaked in a dark gray haze, it must have appeared vaguely metallic (see fig. 8)—perhaps like a sooty ancient bell—but that gray haze turned out to be decades of accumulated dust, grime, and previous restoration materials. In a treatment likely dating to the early twentieth century, conservators had applied wax over the sculpture’s surface to stabilize delaminating paint.^[4] Although the wax would have been transparent when applied, over time it attracted particulate dirt and darkened: the gray visage that graced the museum galleries for decades had never been intended. Like yellowed varnish on an oil painting, the grimy wax layer lent a patina of age to the sculpture but concealed older, and potentially vivid, paint decoration below. In the hope of recovering a more historical appearance, the sculpture was deinstalled in the 1980s and conservators began to examine and carefully expose what was beneath the haze.3

Removal of the wax, however, revealed a surface with a complex history. Rather than a coherent presentation of a single period in the object’s life, it was a palimpsest of deteriorated polychromy from at least three different phases. Looking under the patina revealed an open-ended and unstable identity; the notion of a single true or authentic appearance of the Chicago Guanyin was illusory. If the work was to be restored, therefore, conservators had to ask: toward what essential character or appearance should this material crisis be resolved? Without consensus on how the sculpture should look, conservation work paused in the early 1990s, leaving the sculpture suspended between its past and current conditions. Efforts resumed again in 2017 in conjunction with a technical study undertaken by the authors of this paper. Although the dilemma remained— arguably compounded by the ambiguities of the earlier, unfinished conservation intervention—a growing impetus to re-exhibit the sculpture after several decades of public inaccessibility called for a resolution.4

This paper presents and reflects on the complex materiality of this important Chinese Buddhist sculpture. We begin by presenting the technical findings about the object, which we hope will not only contribute to the growing body of material evidence on polychrome wood representations of this Guanyin type but also elucidate why the sculpture appears as it does today. But any technical investigation can both benefit and haunt those tasked with an object’s interpretation: it brings a richer understanding of the complexity of the object, but with that knowledge comes the awareness that no single interpretation is adequate. In that vein, we then discuss how the Chicago Guanyin’s unstable identity provoked an interpretive crisis for conservators making critical decisions that alter the sculpture’s final aspect.^[5]5

The Benefit (and Curse) of Hindsight: Object as Evidence

Centuries of material degradation and the deposition of particulate dirt, as well as alteration from use and human intervention, will invariably change the appearance of art objects: paint colors darken, fade, or shift tonality, luster dulls, and details are obscured or lost to time. Through technical analysis of a work, it is possible to note the traces of materials applied from the moment of its manufacture to its present; to precisely characterize those materials; and, with luck, to order them into a kind of rough physical biography and determine how they were intended to look. The results of technical study have the potential to correct and supplement observations by the naked eye. This section presents the materiality of the Chicago Guanyin as currently understood through optical examination, instrumental analysis, and comparison with other published sculptures of the same type.^[6] It builds upon and revises previously published material data and approaches the object as the bearer of evidence of its own past.^[7] Although the technical findings are summarized in table 1 (below), here we attempt to collate and interpret the findings into a narrative of the object’s material history. We have opted to present this information chronologically because this most clearly conveys the sculpture’s changing appearance over time and easily maps onto our subsequent discussion of the sculpture’s reception history as evinced by the deliberate alterations made by subsequent viewer-makers.6

Date of Origin

Although the original context of large wood Nanhai Guanyin sculptures like that at the Art Institute is unknown and debated, the dating of their manufacture has primarily depended, in a few cases, on radiocarbon analysis of the wood, and on the assumption that the rise in popularity of the cult of Guanyin during the Song period (960–1279) would have been accompanied by a concomitant demand for Guanyin icons. Radiocarbon analysis on the wood of the Chicago Guanyin offers a range between 1036–1158 for the felling of the tree from which it was carved, suggesting an origin in the Song, Liao (916–1125), or Jin (1115–1234) dynasties.^[8] The wood genus is Paulownia—commonly known as foxglove, a fast-growing tree found throughout China—whose use in sculpture of this period has been suggested as evidence for manufacture and patronage in southern Shanxi Province, which would support an origin in the Song dynasty.^[9] X-radiography points to a solid three-block construction: the head, torso, and proper left (PL) arm comprise one block, the pendant PL leg a second block, and the bent proper right (PR) leg and upper PR arm a third.^[10] Large tenons and dowels with adhesive (see fig. 9) are the primary joining method.7

First Phase: Naturalistic Polychrome

Our ability to reconstruct the details of the first polychromy and derive a sense of its appearance is limited by the fact that the front side of the sculpture was entirely covered over at a later date. Fortunately, the paint scheme is still extensively visible, albeit deteriorated, on the back side, which shows pale pink flesh tones for the body, a blue-and-green striped shawl with yellow trim, and a short overskirt painted in a patchwork of contrasting patterns featuring medallions, floral scrolls, and delicate arabesques (see fig. 10). The stepped color changes in the pattern on the left imitates brocade, wherein color shading must be rendered stepwise with distinctly colored threads, rather than in a continuous blended gradient as in paint media. This detail attests to the deliberately imitative style of this phase, which contributes to a sensorily rich encounter with the sculpture.8

The first polychromy is also exposed in small areas on the front side where later paint layers have flaked off. Close inspection reveals that the short overskirt featured another pattern consisting of large floral shapes outlined in black. The interior color and detail are largely missing from these shapes, but a painted pattern in a better state of preservation on a Guanyin sculpture at the Rijksmuseum, Amsterdam, seems to be a close match.^[11] The delicate red medallion seen on the back also repeats on the overskirt at the PL thigh, establishing continuity between front and back. On the longer robe worn underneath, exposed areas at both knees show a red background decorated with a delicate cut-gold (jiejin, 截金) pattern (see fig. 11); this technique appears on the robes of several other Guanyin sculptures in various patterns.^[12] The jiejin design on the Chicago Guanyin uses four straight intersecting lines to create repeating stars, which is similar (although not identical) to the pattern on the Amsterdam sculpture. Studies of cut-gold (in Japanese, kirikane) patterns on Japanese Buddhist sculpture, of which many more examples survive, find that such star patterns emerge at the beginning of the Kamakura period (1192–1333), again supporting a date for the Guanyin in the Song or a contemporaneous dynasty.^[13] Lower, at the PL shin is an area of curvy, delicate black brushstrokes on a white background. Paint cross-section analysis could not confirm whether this layer belongs to the first polychrome scheme—in which case the contrasting patterns could be ascribed to the longer skirt as well—or served as a preparatory drawing for the subsequent decorative scheme.^[14]9

To supplement these visual observations, we took microscopic paint cross-sections from the hair and crown: the hair was blue, possibly with fine lines of jiejin accentuating the carved lines, and the crown was gilded.^[15] Hardly anything survives from the flesh areas on the front, and we therefore know nothing about how the lips, eyes, and physiognomy were modeled. The eyeballs, represented by two dark glass pieces (either spheres or hemispheres), were set in from the front.^[16] We assume that this first phase also featured an ūrṇā, or divine eye, represented by a precious stone set into a circular hole at the center of the forehead. The stone is now lost, but the concavity that held it remains.10

Although there is ample evidence that in the first phase of decoration the front and back sides were painted as a coherent image (that is, the shawl is blue and green on both sides, the overskirt has the same repeating patterns on both sides, and so on), there is also evidence that the back is a simplification of the front. For example, the border of the short overskirt on the PR thigh is decorated with a wide strip of flat gold but continues to the back as only a stripe of ocher-yellow paint (see fig. 12). Similarly, the jiejin star pattern over a red background on the front is just red paint on the back, without the jiejin. We must therefore curb the urge to extrapolate wholesale from what is seen on the back to the front, as it is evident that the front was more ornately decorated and finished. The rather plain shawl on the back, for example, was likely enhanced on the front with gold leaf or other additions.^[17] We can also deduce from these material simplifications that although the sculpture is carved in the round, it was not meant to be seen, or seen well, from the back. Thus, in its first phase, the sculpture was perhaps placed against a wall or pillar, or in a niche. This in turn suggests that the object could not have been carved or painted in situ.11

In its representation of pale-pink flesh and robes of patchwork embroidery, the first polychrome scheme would have complemented the carved form’s casual pose and draped clothing that conforms to the figure’s contours.^[18] The vibrantly dressed, human-like depiction of the bodhisattva seems notable for its accessible and literally personable aspect, at any moment ready to shift its weight and walk off its perch. A polychromy in a better state of preservation would provide valuable information pertaining to the aims of the artists’ visual choices: for instance, whether—and to what extent—a lifelike optical mimesis of the earthly world was the goal. Were the textile patterns painted to follow the folds of drapery—as appears to be the case in the Lingyan Temple arhats (luohan, 羅漢), enlightened followers of Buddha manifesting as monks (see fig. 13)—or were they imposed flatly on the three-dimensional form? These questions remain provocative and unanswered, due in part to the limited surviving material evidence from the first polychrome phase.12

Second Phase: Gilded Monochrome

The sculpture’s second major phase of surface decoration entirely covered the first paint scheme on the front. Almost all areas were gilded, including the formerly pink-toned body. The colorful drapery was decorated with an intricate raised-and-gilded-line (lifen duijin, 瀝粉堆金) design of clouds and dragons (see fig. 14), and tiny traces of blue paint on top of the residual gilding on the face describe fine blue eyebrows, a thin blue moustache, and delicate blue beard (see fig. 15). The lips were probably deep red, although the paint traces there cannot be correlated conclusively with the gilded scheme. A few features were redone in the mode of the previous scheme: the hair was repainted blue and the crown was regilded. Altogether, the sculpture would have had a comprehensive golden-bronze surface with facial features and hair brightly picked out in contrasting colors. Indeed, it may have been easy to mistake the sculpture for metal rather than decorated wood. Instead of representing a human-like figure wearing clothing as in the first scheme, this gilded monochrome scheme may have suggested a statue of chased and gilt metal. We assume an ūrṇā was visible at this phase, although we do not know if its original material was preserved from the first phase or replaced. Evidence suggests that the ūrṇā was lost or removed later in this second phase, and the cavity was plugged with wood and painted, possibly in imitation of aged gilding.^[19]13

Gilded monochromy has been associated with the Ming (1368–1644) and Qing (1644–1911) periods.^[20] In comparable Guanyin sculptures with gilded monochromy in their material history, paper interleaving layers were found between phases and sampled for radiocarbon analysis.^[21] Results for the paper found directly below the gilded monochrome layer in a Guanyin sculpture in the collection of the Nelson-Atkins Museum of Art in Kansas City, Missouri, corroborate attribution to the fourteenth century.^[22] No evidence of paper interleaving was found on the Chicago Guanyin, but similarities between the sequence of its decorative schemes and that of the Nelson-Atkins Guanyin suggest that a Ming date for the second phase of surface decoration is reasonable.^[23]14

The aims and motivations for implementing the second decorative scheme are not clear. That only isolated fragments of the first polychromy survive below it on the front side could mean that the sculpture’s poor condition prompted a historical restoration, presenting an opportunity to update its appearance. The fragmentary condition of the earlier paint layers, however, could equally mean that they were deliberately scraped off to prepare for a new decorative surface. In either case, a dramatic change in appearance resulted. Notably, the gilding stops abruptly at either side of the sculpture, as though it was not necessary or not possible to access the back. Thus it seems likely that the sculpture was in situ against a wall, pillar, or in a niche at the time of the application of the gilding, which strongly suggests that the alterations were conducted within a continuing context of veneration.15

Third Phase: Partial Overpaint

The coherence of the Ming decorative scheme on the front was later interrupted by a deliberate modification. In this third phase, only the body and face of the figure were covered over in a kind of partial reinterpretation that kept the raised gilding in the clothing. The face and body were painted pink, the eyebrows blue, and the lips bright red, which returned the figure from a metallic appearance to a fleshy one. Any remaining indication of the ūrṇā was completely hidden by this paint layer. The overall effect was of a human-like figure, quite ruddy in coloring and wearing clothing of embroidered gold like the opulent textiles worn by imperial officials of the Ming and Qing dynasties (see fig. 16). Analysis revealed that zinc white, a pigment rarely used until the early nineteenth century, was consistently present in the flesh, under the eyebrows, and in the lips, providing a terminus post quem for the application of this partial overpaint.16

Again, the motivations behind the decorative scheme are uncertain. Thanks to the technical examination, we know that the Ming period gilding on the body and face survives only in scant traces underneath this pink overpaint. Its condition differs markedly from the excellently preserved gilding on the clothing, suggesting a deliberate scraping down of the face and body in preparation for the partial overpaint. Material analysis of the third-phase paint indicates that the white ground layer contains calcite and aragonite, a composition typical for shell white, a pigment commonly associated with Japanese painting and sculpture.^[24] This finding is in contradistinction to the kaolin-based ground layers of the two earlier surface decoration schemes.^[25]17

Fourth Phase: Partial Abrasion

During the fourth phase, in yet another alteration, the top layer of pink paint of the third phase was intentionally abraded to expose the white ground layer below it, which ultimately lightened the skin tone.^[26] Yet again, the motivations are unclear, but the visual effect of the intervention is not without comparison: a Guanyin sculpture in the collection of the Museum of Fine Arts, Boston, underwent a similar transformation, likely in the late nineteenth or early twentieth century. When it was acquired from an art dealer in the 1920s, this sculpture had been completely overpainted white, and not until recent conservation were earlier polychrome schemes revealed underneath.^[27] A Guanyin sculpture at the Princeton University Art Museum shows traces of white paint on its surface as well.^[28] These shifts toward white may have been concerned with conforming the sculptures to modern expectations for representations of Guanyin. While there were many manifestations of Guanyin depicted in Middle Period China (c. 900–1200), by far the most ubiquitous and popular manifestation since the Qing dynasty (1644–1911) is known as the White-Robed Guanyin (Baiyi Guanyin, 白衣觀音).^[29] In addition to being female, the White-Robed Guanyin is almost always depicted in paintings with white skin, and in sculptures in blanc de chine, or Dehua porcelain—which is to say, completely white (see, for example, fig. 17). In painted depictions specifically, even the Water-Moon Guanyin has been associated with white or pale skin since the tenth century, an association that became further entrenched as the iconography of the Water-Moon Guanyin merged with that of the White-Robed Guanyin in painted depictions.^[30] Seen in this context, the modern shift toward white skin tones in large wood sculptures of Guanyin may have been influenced by more common images of the deity in other media.18

A Crisis of Material and Meaning

Through this tour of the layered materiality of the Chicago Guanyin, we now have a better sense of the palimpsest that confronted conservators when the grimy wax patina was removed. On the back was a coherent, if distressed, surface from its Middle Period phase, representing the human-like body of a bodhisattva wearing elaborate monastic robes. On the front, opulent Ming gilding in the drapery was juxtaposed with a severely compromised jumble of later interventions in the body and face. While the torso was reddish and mottled, the face and arms were white with a heavy craquelure pattern. These conditions contributed to an incoherence that disrupted the aesthetics and legibility of the sculpture. The remains of the partial overpaint were also physically unstable and actively flaking, presenting a risk to older material below. We also reasoned that the partial overpaint, stripped to its underlayer, no longer expressed the third phase’s intentions for pink flesh. And, as a fourth phase in its own right, the “return” to white skin was based on a notion of an authentic appearance of Guanyin that did not factor in the unique material history presented by the object itself. These judgments about the remains of the third phase of polychromy prompted us to decide to remove it when conservation work resumed in 2017.^[31] Since the Ming gilding in the clothing was the predominant material factor determining the appearance on the front, the aim was to approximate the appearance of the Ming phase in the face and body, thus keeping the sculpture within a single, coherent, and historical phase of its material history.19

Removal of later layers fully exposed the extent of the damage to the Ming phase monochrome in the face: the gold leaf was almost totally gone, and only the white and red preparatory layers remained, but in a disfiguring manner reminiscent of a skin disease (see fig. 18). In conservation, decisions about loss compensation are guided by the related concept of wholeness: “Logically, the presence of loss depends on a countervailing opposite: the notion of wholeness. Loss is affected by an expectation of what a complete form should be.”^[32] In the case of the Chicago Guanyin, the complete form that historically corresponds to the gilding in the drapery would be a similarly gilded face and body.^[33]20

Accomplishing this in practice, however, would require a heavy-handed modern intervention over much of the sculpture, resulting in an unacceptable decrease in its uniquely aged character. A more conservative approach would follow the lead of the object’s material condition by shifting the face’s overall white-red gestalt toward the more homogenous red tones on the rest of the body, especially the torso. This too is problematic, however, since there is no evidence that this figure was intended to be red.^[34] Compensating in red tones would in effect render the appearance of the figure historically, and perhaps iconographically, inaccurate. Yet another approach would be to allow the modern expectation of a pale-skinned Guanyin to guide restoration decisions: in practice, this would require minimal retouching in the face (which was already mostly white) but heavy retouching and covering of historical material in the torso. We considered other treatment options, including not to compensate at all. Of course, no single option perfectly suited the material complexity of the object.21

The poor condition of the sculpture’s body, especially in the crucial area of the face, ultimately left the appearance and meaning of the object open and unspecified, generating an interpretive crisis for the conservation team. Its layered materiality, rich biography, and compromised state contained several potential identities, or expressions of the deity, but which was most authentic? The polysemous nature of objects can be fulsomely discussed and adequately conveyed in text, but designing a treatment that honors that multiplicity is much more challenging, given that the actual physical aspect of the object will be altered. Thus, while a conservator may agree with scholars of art history, material culture, semiotics, and other allied disciplines that there is no single “correct” or “authentic” appearance for a given object, the answer to the practical question—in the case of the Chicago Guanyin, to which color should the figure’s body be restored?—still must be convincingly supplied and materially achieved.22

The conservation dilemma around the Guanyin was further intensified in one important respect: in specifying its visual aspect, the restoration might participate in unintentional interpretation and redefinition of the object’s meaning and status, fixing it to one identity when multiple are valid. The aesthetics, legibility, aged character, and historical significance of the sculpture were the main factors influencing treatment decisions, but the conservation team was keenly aware that its decisions would have potential implications for future material and visual research on the sculpture. For instance, conserving the object so it reflects just one phase in its life might hinder exploration of the significance behind the historical changes to its material identity and visual appearance. In its initial phase, the bodhisattva was presented as a human-like, dynamic figure both in form and surface polychromy. In its second phase, the body and clothing were golden in color, at the very least expressing the visual properties of gold and possibly imitating a metallic object. These deliberate changes express choices about the visual representation of the bodhisattva that likely correspond to a shift in notions around the visuality of the divine body and of the icon’s efficacy. How did viewers and makers conceptualize these changes and what they saw? Beyond expressing changing stylistic preferences, what might the divergent polychromies of flesh and metal represent?23

It is possible that this variation reflects changing beliefs about the nature of representation itself. Scholarship on Chinese Buddhist reception of much earlier sculptural representations of the Buddha tracks shifts in the understanding of these objects’ ontology, from the “true visage” (zhenrong)—an identical replacement for the divine entity itself—to “as if real” (ruozhen), in which the material representation invokes or manifests the absent divine entity.^[35] Buddha sculptures were also understood as “auspicious images” (ruixiang), which are acknowledged as made by human hands but nevertheless considered authentic, even miraculous, representations of the divine entity.^[36] These three categories apply not only to representations of the Buddha but also appear in seventh-century texts discussing images of bodhisattvas as well.^[37] Did the historical changes to the surface appearance of the Chicago Guanyin reflect a shift in its status as representation? Current scholarship has limited understanding of how these abstract concepts of “the real” could be instantiated in material form, if at all. More research on the changing visual identity of the Chicago Guanyin, and comparable objects, may contribute to the discourse.24

Similarly, the later occlusion of the ūrṇā might signify a change in ontological status of the sculpture: perhaps its removal was part of a ritual deactivation of the Guanyin, or perhaps its concealment corresponded to a judgment about the object’s diminished ability to effectively represent the deity due to its aged appearance. Each of these propositions is conjecture. No cavity other than that of the ūrṇā, nor any inserted items such as relics or sutras to consecrate the sculpture, were detected within the Guanyin.^[38] But might its many polychromies—each in a sense concealed within a cavity created by the next encasement of paint—have performed a consecratory function? Rather than each previous polychrome phase being simply replaced by the newer layer, might the earlier layer “within” have served as an activating material or source of sacred authority?25

It is merely speculation to ask whether deliberate and dramatic changes to the sculpture’s polychrome surface constitute anything other than an expression of stylistic preference, but such questions are essential to assessing the art historical significance of the life and afterlife(s) of the sculpture. Iconography and ontology are just two modes with which to situate and interpret the material data of the Chicago Guanyin in the broader visual culture of Middle Period China. The patron-makers’ reasons for altering the sculpture may originate in a variety of considerations, including but not limited to aesthetic, economic, and political factors. The study of how concepts of the divine body in the form of sculptural icons changed over time will greatly benefit from new material data on deliberate modifications to sacred objects. Close examination of visual trends and material changes to secular representations, such as statues of imperial figures produced during the Middle Period, would provide valuable comparative data.^[39]26

At stake is the fundamental question: what precisely is the artwork to be conserved? Until we have a richer understanding of alterations to sacred and secular objects, we cannot satisfactorily answer this basic question, and critical interpretive decisions will continue to weigh heavily on conservators confronted with an object whose compromised condition renders its identity open and unstable. Publication of material data, treatment protocols, and the processes behind conservation decision-making is a necessity. But research collaboration between conservators and scholars of allied disciplines is crucial to our ability to articulate, with specificity, how conservation affects both the material and immaterial characteristics of an object, which continues to evolve after being restored. Further collaboration between conservators, scientists, curators, and art historians is much needed, not only when making conservation and restoration decisions about works of art, but in identifying fruitful avenues of research that will inform and undergird our collective interpretation of the material evidence that these complex objects embody. Recognizing that for most objects there is no single authentic mode, the collective act of analysis, documentation, examination, and interpretation will ultimately preserve the multivalent and polysemous nature of these unique and powerful objects.27

The Chicago Guanyin in Modern Secular Reception

The discipline of art history has long recognized how fraught it is to interpret works of art “removed in time and place” from us, works whose contingent meaning creates “a real danger of misreading even the most elementary feature.”^[40] And this is so even when the material integrity of the work we are reading or misreading is relatively intact (if not its original location, context, or purpose). How then is a conservator to approach an object so materially disrupted from its past identities that crucial aspects of its appearance are open to interpretation? As this paper demonstrates, the stakes of this question are hardly limited to aesthetic matters such as wholeness, legibility, and visual appeal. Art historians, for example—despite bringing diverse concerns and questions to the objects they study—often converge on the idea that a work of art is an index of the context of its making. However, as the Chicago Guanyin exemplifies, the material identity of a work of art is rarely a product solely of its original moment of facture. Rather, that “context of making” continues up to and through the modern conservator-scientist’s interpretive actions. It is in this dynamic and unstable zone of shifting identities and meanings that art history and conservation could so fruitfully benefit from working together.28

Without recourse to external criteria of authenticity and absent specific knowledge of the signification of materials in Middle and Late Imperial Period China (the Ming and Qing dynasties, about 1300–1800), decisions about the conservation treatment necessitated by the Chicago Guanyin’s material instability were ultimately based on the values and belief systems of the modern viewer as conservator-scientist-curator. Fear of an anachronistic presentation (one that mixes two or more phases of polychromy that were never seen together) and reverence for the unique materiality and long trajectory of the sculpture as ascertained by empirical observation and scientific analysis meant privileging the age value and historic value in the decorative scheme of the Ming period: the body and face were toned in reddish-golden hues to mimic and integrate surviving traces (see fig. 19). Adherence to professional codes of conduct (e.g., minimal intervention, reversibility of treatment) translated, in practice, into an unusual retouching technique using dyed tissue paper that can be removed with a cotton swab.^[41]29

The conservator’s professional concerns are far from those of the Middle Period makers and viewers. Yet fear, reverence, and devotion describe an attitude perhaps not so different from the phenomenological experience of worshippers in Middle Period China encountering the sculpture. The activities of close looking, knowledge and truth seeking, and image consecration are as much a part of the sculpture’s modern secular reception as they undoubtedly were in its historical Buddhist contexts. In this respect, it may not be unreasonable to consider this particular conservation treatment as the most recent instance in a long series of widely ranging responses to an object in evolution. The following passage, written about an object far removed in space and time from the origins of the Guanyin, nevertheless seems apt: “in many respects the meaning of the work is imposed on it by users and viewers after its manufacture …. In time, owing to the care that is given to the figure its features change; the work becomes smoother, softer, and the whole surface assumes a beautiful sheen … [which] makes it clear how important the user is both in giving meaning to the work and, at least in some cases, in modifying its form.”^[42]30

During the 2017 conservation treatment, we approached the Chicago Guanyin as the evocative physical form of a spiritual icon that was conceived in the Middle Period and reinterpreted during the Ming dynasty. This definition of the object, like any given by previous makers and viewers, is contingent and temporary. What this case study makes clear is that conservators are no less haunted than art historians by the visual effects and expectations of an object. On the contrary, the privilege and responsibility of directly manipulating the materiality of an object in the hope of enabling it—whatever it may be—to endure, makes conservators’ plight that much more acute.31

Appendix: Analytical Methods

Pyrolysis-GC/MS with thermally assisted hydrolysis and methylation (THM-Py-GC/MS): Samples of a few micrograms were placed in Agilent microvials with tetramethylammonium hydroxide reagent (1.5 μL of a 2.5% solution in methanol) in an Agilent Thermal Separation Probe and inserted into the Multimode Inlet of an Agilent 7890B GC. The GC was equipped with an Agilent HP-5ms Ultra Inert column (30 m, 0.25 mm i.d., 0.25 μm film) and interfaced to a 5977B MS. The inlet, operated in splitless mode, was ramped from 50°C to 450°C at a rate of 900°C/min to perform THM and pyrolysis. The final temperature was held constant for 3 min and then decreased to 250°C at a rate of 25°C/min. The GC oven was programmed from 40°C to 200°C at 10°C/min, then to 310°C at 6°C/min, and held isothermally for 20 min; total run time was 54 min. The MS was run in scan mode (m/z 35–550 from 5 to 25 min, and 50–700 from 25 min).32

Scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS): Morphological observation and elemental characterization were carried out on cross sections using a variable pressure SEM (Hitachi S-3400 N-II) equipped with Oxford x-act SDD. Accelerating voltage was 20 kV, pressure 80 Pa, and probe current 70–90 for EDS. Samples were mounted on carbon tape on an aluminum pin stub mount. SEM-EDS analyses were performed at the Electron Probe Instrumentation Center (EPIC) facility of the Northwestern University Atomic and Nanoscale Characterization (NUANCE) Center at Northwestern University, Evanston, Illinois.33

Raman spectroscopy: Samples were analyzed using a Jobin Yvon Horiba LabRAM 300 confocal Raman microscope equipped with multiple excitation lines (532, 632.8 and 785.7 nm), an air-cooled CCD detector, holographic notch filter and 1800 lines/mm dispersive grating. A 100× objective was used and power at the samples was kept below 1 mW by a series of neutral density filters.34

Fourier transform infrared spectroscopy (FTIR): Samples were mounted on a Specac diamond compression cell and analyzed in transmission mode between 4000 and 400 cm⁻¹ at 4 cm⁻¹ resolution and 256 scans per spectrum using a Bruker Hyperion microscope with MCT D315 detector, interfaced to a Tensor 27 spectrometer bench.35

Proteomics: Protein extraction and enzymatic digestion with LysC and Trypsin was performed as described in Mackie et al.^[43] The resulting peptides were desalted on C18 spin columns and analyzed by LC-MS/MS using a DionexUltiMate 3000 Rapid Separation LC system and a linear ion trap - Orbitrap hybrid Elite mass spectrometer or QEHF (Thermo Fisher Scientific). The LC was equipped with a 75 μm × 10.5 cm PicoChip analytical column packed with 3 um ReproSil-Pur® beads. The flow rate was kept at 300 nL/min. Solvent A was 0.1% FA in water and Solvent B was 0.1% FA in ACN. The peptide was separated on a 120-min analytical gradient from 5% ACN/0.1% FA to 40% ACN/0.1% FA. The mass spectrometer was operated in data-dependent mode, source voltage was 2.40 kV and the capillary temperature was 275°C. MS1 scans were acquired from 400 to 2000 m/z at 60,000 resolving power. The top fifteen most abundant precursor ions in each MS1 scan were selected for fragmentation by collision-induced dissociation. Proteomic analysis was performed at the Northwestern Proteomics Core Facility. Raw data were searched against a SwissProt database (January 2017), followed by other searches with different homemade databases downloaded from UniProt, and processed with MaxQuant software version 1.6.1.0. For specific parameters refer to Mackie et al.^[44]36

Banner image: Detail of fig. 1.37