Inpainting

Inpainting ANTONIO IACCARINO IDELSON Conservator, Equilibrarte, Italy LEONARDO SEVERINI Independent Conservator, Italy The noun inpainting is a prepositional compound with “in”: in + painting, that is, “painting inside.” It seems to have appeared in the conservation literature of the United States in 1935 (Metzger, Maines, and Dunn 2011), when it was proposed by G. L. Stout and described as “placement of new paint in the lacunae of the old film” (Stout 1935). Buck and Stout (1940) offered a definition of inpainting as “compensation of losses with no new paint put over that which is old and original,” thus avoiding arbitrary intervention, and distinguished it from overpainting which goes “beyond mere compensation in the area of loss.” This approach characterizes the modern profession of “conservator,” which was then being established in Europe and in the United States; conservators were replacing the outdated approach of the restorers of the previous generations, whose overpainting often obliterated and modified original parts of the painting. “Retouching,” a more widespread term, though older and less specific, describes the artist’s action of perfecting his or her painting with touches of color. In the United States more than in Europe, the term “inpainting” is preferred to retouching, because it speaks to the aim of modern conservation practice to introduce new ethical standards and techniques. Compensation for losses has been a crucial point in all theoretical and ethical approaches to conservation (Hill Stoner and Rushfield 2012). The conservator may reduce the visual disruption caused by the loss or alteration of the original paint layers by adding color, either through mimetic (imitative) retouching or in a differentiated way. Being among the conclusive steps of a conservation treatment, inpainting is also the one that acts as mediator in the relationship with the public and facilitates understanding of the painting. It is therefore not surprising that inpainting is often identified with the entire process, especially since to restore literally means to reinstate the missing parts of an object. Pietro Edwards, chief restorer for the public paintings in Venice in the late eighteenth century, recommended the least possible amount of integration, mostly within the losses, and with varnish-bound colors that could be removed with no damage to the original painting. The instructions in his writings reveal a deep understanding of the realities of the process—an understanding that derives from his personal involvement in the treatment of paintings (Tranquilli 1996). Imitative and interpretative overpainting prevailed until the beginning of the twentieth century, when a more rational and respectful approach was reinstated in the field of painting conservation. The International Conference for the Study of Scientific Methods for the Examination and Preservation of Works of Art, held in Rome in 1930, is considered to have been a seminal event for the establishment of the modern discipline of conservation (International Museums Office 1997). The subject of retouching held a central place in that discussion, identifying the distinction between the modern imitative techniques and the traditional “deceptive” ones. The importance was made clear of limiting the intervention to the areas of loss, working with reversible materials, and ensuring the recognition of inpainted areas through photographic documentation. At the Rome Conference Helmut Ruhemann (1968) proposed to work on differentiated retouching; but later on he went back to mimetic reintegration, as no method seemed satisfying. Imitative inpainting is based on a long-standing tradition and its principles and development are empirical rather than based on philosophical reasoning. Indeed, imitative techniques are those most often used at an international level. Prioritizing the unified appreciation of the painting, they allow for the important element of the conservator’s subjectivity when facing the great variety of damages sustained by the original paint layer. The Encyclopedia of Archaeological Sciences. Edited by Sandra L. López Varela. © 2018 John Wiley & Sons, Inc. Published 2018 by John Wiley & Sons, Inc. DOI: 10.1002/9781119188230.saseas0330 2 I N PA I N T I N G The need for shared and structured principles has motivated the redaction of guidelines for ethics. In the Code of Ethics and Guidelines for Practice issued by the American Institute for Conservation, we read (https://www.nps.gov/ training/tel/Guides/HPS1022_AIC_Code_of_ Ethics.pdf): Any intervention to compensate for loss should be documented in treatment records and reports and should be detectable by common examination methods. Such compensation should be reversible and should not falsely modify the known aesthetic, conceptual, and physical characteristics of the cultural property, especially by removing or obscuring original material. (23: Compensation for Loss) The concept of “authenticity” is connected to that of “autography” and even to that of “truth”—notions that have always aroused respect and reverence. At the core of the debate in the history of restoration and conservation, the conflict between authenticity and unified appreciation of the artwork has seen solutions ranging from stylistic reinterpretation to archaeological presentation of autograph fragments of paint layers. Nevertheless, the definition of authenticity has changed over the centuries, moving away from the “competitive” approach of the Renaissance and baroque periods, when older works were reshaped so as to acquire new value instead of losing it. During the Enlightenment, the progressive application of the scientific method to all the fields of culture directed new attention to the original materials, as demonstrated in the work of Pietro Edwards. A contemporary definition of authenticity is expressed in the 1994 Nara Declaration on Authenticity (available on the UNESCO website, at https://www.icomos. org/en/about-icomos/179-articles-en-francais/ ressources/charters-and-standards/386-thenara-document-on-authenticity-1994). According to the Nara statement, the conservation of cultural heritage is rooted in the values attributed to heritage by the stakeholders. Values, and authenticity more than others, depend on the degree to which the information sources related to them are credible or truthful. Such evaluations may differ from culture to culture, and even within the same culture. It is thus not possible to base judgments of value and authenticity on fixed criteria. The Italian approach to the problem of authenticity versus the subjectivity of the conservator is grounded in the comprehensive theory of conservation developed by the art historian Cesare Brandi between the 1940s and the 1960s as he aimed to guide the treatment of losses through a philological and critical approach (Brandi [1963] 2005). His best known concept of a “theory of restoration” (teoria del restauro, Brandi [1963] 2005) is that of the recognizable integration of losses achieved through the tratteggio verticale (“vertical hatching”). Similar hatching techniques, such as the selezione cromatica (“chromatic selection”) and the astrazione cromatica (“chromatic abstraction”), were proposed in Florence by Umberto Baldini in the 1970s (Casazza 1981). The teoria del restauro was developed within the philosophical discipline of aesthetics and had important contributions from Gestalt psychology, namely regarding the ability of the human brain to visually integrate specific kinds of losses and to differentiate between the respective roles of image and background—which proved to be particularly useful for works of art built with a stratigraphic sequence of distinct layers. These considerations resulted in a reduction of the amount of integration of losses that was necessary in order to establish a correct balance between the aesthetic and the historical cases. The typological differentiation of losses according to their position in the stratigraphy—whether they affected intermediary layers of paint or only the uppermost pictorial surface—was a key element. The choice that was considered to be the most respectful one was to treat the loss chromatically, in order to have it recede to a lower layer in the stratigraphy, thus reducing its perception by assimilating it into the background. A superficial paint loss can be assigned the perceptual value of an area where the preparatory layers, made visible by the lacuna, are easily interpreted as having that value. These areas looked clean and consistent and seemed to belong recognizably to a lower layer (with respect to color, surface texture, and level); thus their disruption of the readability of the painting was considerably reduced. This emphasized the original, surviving paint surface and allowed it to be more greatly valued. This I N PA I N T I N G “level switch” is as effective on paintings with a precise and constant stratigraphy (e.g., most easel and mural paintings) as it is on a variety of other artifacts (e.g., painted wooden sculptures and ceramics). Within the teoria del restauro, this technique—which, strictly speaking, is not inpainting but a different method for the treatment of losses—is always deemed preferable, though carefully weighed against the aesthetic limitations it imposes. For losses in which the reconstruction of the image is deemed necessary and possible without arbitrary interpretations, the teoria del restauro proposes the use of a technique of inpainting that is recognizable only through close examination: tratteggio. Thin vertical strokes of highly contrasting colors, traced in very close proximity to one another on the white base of the gesso fills, reconstitute the image with sufficient accuracy to guarantee the complete illusion of the absence of a lacuna. The broader influence of the teoria del restauro has been limited by several factors. Primary among these is its limited dissemination outside the Romance-speaking world, as it was not translated before the 1990s. Although many European countries have shared Brandi’s approach and methods, limitations arise, also in Italy, from considerations about the supposed need for a trained eye in the observer and about the higher costs of a longer process of loss compensation. Despite the fact that the teoria del restauro proposes a structured formula for the reintegration of losses (Mora, Sbordoni-Mora, and Philippot [1977] 1984), it also leaves margins for the necessary subjectivity of the ultimate choice among the various possibilities that each problem presented by the painting allows. Although both the mimetic and the recognizable inpainting methods are viable, for each specific problem, the process that leads to a solution can only be guided by gradual comprehension, which requires lateral thinking and is based on trial and error. More recently, by an interesting coincidence, the term inpainting has also been adopted in software language, in the reconstruction of missing parts in digital photographs and videos. Algorithms that extrapolate information from the surviving areas around these missing parts are used to reconstruct them according to the criterion of the minimum visual interference. 3 These semiautomated methods are structured according to the mechanisms of human visual perception described by Gestalt psychologists (among others) and are proposed for the treatment of missing parts in digital photographs of old paintings (Schönlieb 2015). Such techniques will soon become available for use in combination with digital printing methods, which have recently been successfully used for transferring printed images in the losses of wall paintings in order to assist and reduce manual inpainting. Prefabricated elements introduced in the integration work carried out by the conservator may add a new level of efficiency to the process and make the integration of large losses more cost-effective. When heritage has been damaged by war or by natural disasters, complete reconstructions are often asked for in order to preserve its symbolic meaning in terms of collective identity. The decision process ought to be rooted in the clear understanding of the requirements of the stakeholders, which need to be harmonized with the physical condition and needs of the artifact. In a time of frequent war conflicts and rapid technological developments, conservators need to exert special awareness. In conclusion, if inpainting has been the object of reflections and successful prescriptions, the part of it that is performed on the original paint has been, and still is, considered risky, even though it is now always performed with reversible paints. As a matter of fact, inpainting involves the risk of regressing to the practices of overpainting, from which the modern profession has moved away with determination. Inpainting is defined alongside its process and intrinsically connected with its action. For this reason most of the responsibility stays with the “critical action” of the conservator, which in turn depends on his/her sensitivity while facing constantly changing challenges. The maturity of the profession, nowadays guaranteed by the availability of highly specialized conservators and by their close interaction with the other professions, allows relying on a higher level of awareness at an international level. Nevertheless, most of the theoretical frameworks of inpainting have been produced by professionals who do not have direct responsibility (Muñoz Viñas 2005) for the operations performed on the artifact. 4 I N PA I N T I N G The new technological frontiers and the aesthetic demands of a world dominated by perfect images in an “age of tourism” raise new challenges for conservation ethics. In a global society that seems to be progressively less willing to accept the presence of imperfections in artifacts with a shared value, a bigger effort to discuss and bridge between professionals and the other stakeholders seems to be more urgent by the day. SEE ALSO: Archaeology and Tourism; Ethics in Conservation; Experts and Stakeholders REFERENCES Brandi, C. [1963] 2005. Theory of Restoration, edited by G. Basile. Florence: Nardini. Buck, R. D., and G. L. Stout. 1940. “Original and Later Paint in Pictures.” In Technical Studies in the Field of the Fine Arts, 1932–1942 (facsimile edition), edited by G. L. Stout, vol. 8: 123–50. Cambridge, MA: William Heyes Fogg Art Museum, Harvard University. (Reprint New York: Garland, 1975.) Casazza, O. 1981. Il restauro pittorico nell’unità di metodologia. Florence: Nardini. Hill Stoner, J., and R. Rushfield. 2012. Conservation of Easel Paintings. New York: Routledge. International Museums Office (IMO). 1997. Manual on the Conservation of Paintings. London: Archetype. Metzger C. A., C. Maines, and J. Dunn, eds. 2011. Painting Conservation Catalogue, vol. 3: Inpainting. Washington, DC: American Institute for Conservation. Mora, P., L. Sbordoni-Mora, and P. Philippot. [1977] 1984. Conservation of Wall Paintings. London: Butterwoths. Muñoz Viñas, S. 2005. Contemporary Theory of Conservation. Oxford: Elsevier Butterworth-Heinemann. Ruhemann, H. 1968. The Cleaning of Paintings: Problems and Potentialities. London: Faber & Faber. Schönlieb, C. 2015. Partial Differential Equation Methods for Image Inpainting. Cambridge: Cambridge University Press. Stout, G. L. 1935. “A Museum Record of the Condition of Paintings.” In Technical Studies in the Field of the Fine Arts, 1932–1942 (facsimile edition), edited by G. L. Stout, vol. 3: 200–16. Cambridge, MA: William Heyes Fogg Art Museum, Harvard University. (Reprint New York: Garland, 1975.) Tranquilli, G. 1996. “Aspetti tecnici dell’attività di Pietro Edwards: Metodologia di intervento e materiali utilizzati per il restauro dei dipinti su tela.” Bollettino d’arte 96–7: 173–88.