Conservation of Easel Paintings

Joyce Hill Stoner, Rebecca Rushfield, Joyce Hill Stoner, Rebecca Rushfield

• Publisher: Routledge
• Year: 2020
• ISBN:
  9780429680960
• Edition: 2
• Topic: Arte
• Subtopic: Arte generale

Conservation of Easel Paintings, Second Edition provides a much-anticipated update to the previous edition, which has come to be known internationally as an invaluable and comprehensive text on the history, philosophy and methods of the treatment of easel paintings.

Including 49 chapters written by more than 90 respected authors from around the world, this volume offers the necessary background knowledge in technical art history, artists' materials and scientific methods of examination and documentation. Later sections of the book provide information about the varying approaches and methods for treatment and issues of preventive conservation, as well as valuable reflections on storage, shipping, and exhibition. Including exciting developments that have taken place since the last edition was published, the book also covers new techniques of examination, especially MacroXRF scanning and Reflectance Transmission Imagery. Drawing on research presented at recent professional conferences, information about innovative methods for cleaning modern and contemporary paintings and insights into modern oil paints is also included.

Incorporating the latest regulations and understanding of health and safety practices and integrating theory with practice throughout, Conservation of Easel Paintings, Second Edition will continue to be an indispensable reference for practicing conservators. It will also be an essential resource for students taking conservation courses around the world.

Part I

Technical art history, examination, documentation, and scientific analysis

1

Art technological source research

Documentary sources on European painting to the twentieth century, with Appendices I–VII

Jilleen Nadolny, Mark Clarke, Erma Hermens, Ann Massing, and Leslie Carlyle

1.1 Introduction

To successfully care for cultural heritage, conservators must have an extensive understanding of the complex material and historical nature of objects. Professionals working in conservation and its related fields have increasingly favoured a multidisciplinary approach as the most effective manner in which to study paintings. Direct study of the objects, combined with scientific analysis and scholarship of contemporary texts of many different types, can provide both technical information and a unique insight into painters’ materials and methods. This chapter will review the latter type of material: the available types of historical documentary sources concerning the physicality of paintings.

The study of the materiality of art has increasingly been recognised as an important field, often referred to in the early twenty-first century as ‘technical art history’. Technical art history is interdisciplinary and can illuminate studies of art by combining art-historical research with detailed examination of the artefacts themselves, possible reconstructions of materials or methods, and scientific analysis. Technical art history frequently also includes scholarship concerning documentary sources, recently termed ‘art technological source research’ (ATSR). Although these activities often evolved alongside conservation, they may equally be the work of specialists. In 2005, a Working Group, ‘Art Technological Source Research’ (ATSR), was established within the International Council of Museums-Conservation Committee (ICOM-CC). Recent ATSR published conference proceedings can be recommended as examples of good practice (Clarke et al., 2005; Kroustallis et al., 2008; Hermens and Townsend, 2009). By using a holistic methodology that combines the study of documentary material along with reconstructions (see Chapter 2), scientific analysis (Chapters 17–22), and traditional art-historical research, a new degree of interpretative precision can be achieved (Clarke, 2009).

Sources for the history of art technology come in many forms. They can encompass realia (historical tools and materials), visual documents (images – self-portraits, illustrations for books, photographs – or even films of artists at work), or various textual sources. This section will concentrate on written sources, which may include technical treatises, manuals, recipe collections, colourmen’s ledgers, artists’ correspondence and diaries, and transcripts of artists’ interviews. These testimonies allow researchers and conservators to see the past with a broader understanding of the possibilities and limitations of artistic practice at the time the materials and techniques were used, and so to come to an improved appreciation of the relation of artists to their materials.

There are substantial numbers of documentary sources that survive. The present chapter therefore is not meant to be comprehensive, but rather should be read as an introduction to the ATSR field. The importance of context and background knowledge for source research cannot be overstressed. For example, while it would seem logical to assume that most artists’ treatises were written by artists for artists, in fact (as will be demonstrated) this was not always so. It might seem likely that published collections of technical information were commonly in use at the time of publication, but this was also not consistently the case. Thus, this chapter will outline the types of sources to survive from different periods, including appendices of the most important, influential, or well-known texts, and point to more comprehensive published bibliographies. But perhaps more importantly, it also aims to provide an introduction to the effective use of such sources: their value and use, their strengths and limitations, and suitable methods for their interpretation.

1.2 Interpretation

For anyone wishing to work with historical texts, it is important to be aware of the various forms in which such sources are available for study. Many texts of more recent date will be available in printed editions; others are easily accessible as re-publications. However, source research is not always so straightforward. Unique, handwritten texts (manuscripts) may be hard to decipher due to the style of handwriting or the use of abbreviations. When handwritten texts are copied (transcribed), this should be a literal rendering of the original handwritten text, either in another hand, or in printed form. The text may also be translated from one language to another. In each of these stages – translation, transcription, publication – mistakes and uncertainties may arise. Of all of these, translation is perhaps the most difficult, especially if the translation happens many decades or centuries later, as the exact meaning of the technical terminology may be lost and open to interpretation and re-interpretation. It is for this reason that new editions and translations of famous texts continue to appear (both the treatises of Cennino Cennini and Theophilus – see discussions below – each exist in over 35 editions, with more in the works). In the nineteenth century and the first half of the twentieth, translations and transcriptions were often reviewed. In reviews, scholars engaged in constructive debates, which often added further levels of understanding to the published versions of older texts. Unfortunately, this useful tradition is now often overlooked.

In order to understand and interpret manuscripts, scholars must consider all available forms of comparative material, including texts from the same period (where, with luck, one may find other examples of a term in use and, with great luck, even a definition), not excluding current scientific data and reconstructions. Since borrowing and copying from older sources was commonplace, recipes may not necessarily be contemporary with the handwriting or, later on, with the printed book. However, this tendency to recycle becomes less marked with works of a more modern date, and certainly the concept of scholarship in the modern sense is clearly evident in some eighteenth-century sources, and by the end of the nineteenth century it is common.

In general, use of a text should be approached with care since it reflects an interpretation, making the act of citing it an interpretation of an interpretation, and in the case of older texts, many times removed. When one wishes to use a text, it is useful to go through a brief checklist:

•When and where was the text written?

•By whom and for whom was it written?

•In what historical context was it written?

•What level of interpretation (transcription, translation, interpretation) has the text undergone, and what is the most recent/most respected interpretation of it?

The form that publications take reflects the priorities of their times. We may take, as an example, texts on pigment recipes. In the Middle Ages, such recipes were often compiled and copied by hand by monks (not painters) eager to preserve any and all forms of useful knowledge. In the late nineteenth century, texts on pigment manufacture and permanence could be written by chemists for the paint industry, not only for artists. Different again are the texts dealing with pigments produced by Renaissance humanists, which often discussed materials summarily, as their main objective was to convince the educated reader of the noble status of the painter, long seen as merely a craftsman (Clarke, 2008).

1.3 Technical terminology

In translating these technical documents, terminology remains contentious. Handwritten texts (especially those of the Middle Ages) suffer from inconsistencies in scribal copying, from copyists’ interpretations of earlier terminology, and from a lack of standardised spelling or the use of now obscure abbreviations. The spelling and function of some words changed over time and from one language to another (e.g. ‘minium’ and ‘vermilion’, which have exchanged meanings more than once), and many terms had multiple definitions; thus a word may not have meant what it appears to mean today. The lack of standardisation of substance names, particularly those of plants, can sometimes preclude their definitive translation. Certainty is likewise impossible in the elucidation of certain specific procedures. The technical literature is replete with examples that demonstrate circular reasoning, where researchers used published translations of recipes to arrive at interpretations of processes, while translators had used these same interpretations to suggest the meaning of a puzzling word or passage.

While source material can be concise and clear, establishing meaning should be approached with caution both when examining a copied version of a centuries-old text and when reading a printed tome on pigment manufacture from a hundred years ago. A single, fixed definition may not be possible. Equally, extreme circumspection when using or preparing translations is indispensable, and some reference should always be made to the original where feasible.

1.4 Text vs practice

The disjuncture between practice and text appears to be most characteristic of the early Middle Ages before ca. 1200, but remains an issue in certain works through to the eighteenth century. A spectrum of reliability is found; while some of the many instructions found in the treatises were clearly practical, others were not. New contributions were added gradually to the copied, older material that formed the compilations, and later, with the introduction of the printing press, older works were frequently simply repackaged or lightly updated. Scholarship is making progress in defining this relationship between text and practice. As a rule of thumb, texts in vernacular European languages (rather than in Latin) that appear from the fourteenth century onwards tend to be more direct records of contemporary workshop practices.

1.5 History of art technological source research

The earliest technological texts date from at least the seventh century bc (Assyrian recipes for ceramic glazes and coloured glass, arguably copies of earlier material). Art technological source research, including texts covering painting, is known to date from the first century, when Pliny and Vitruvius incorporated earlier texts into their own treatises (see below). Their texts appear to have been written for the ‘general reader’ rather than for the professional practitioner. This reworking of technical material for a non-technical audience has continued to the present.

Art technological source research as it is now understood began with the eighteenth-century publications of texts such as Lodovico Antonio Muratori’s Antiques Italicae medii aevii (1738–42, 6 vols), which included the important ‘Lucca Manuscript’, also known as the Compositiones ad tingere musiva, a recipe compilation from ca. 800 (Kirby, 2008: 8). Many eighteenth- and nineteenth-century publications simply reproduced the text of manuscripts, thus making them available to a wider public. This approach is typical of the contemporary antiquarian interest in recording textual documents of historic interest. In such cases, texts were published with little or no commentary or with wildly inaccurate interpretations.

An interest in texts was one necessary factor for the successful development of source research; however, it was not enough. Without supplementary information (trial reproductions, observations made from original objects, and, later on, analytical data), it is impossible to decipher the technical terminology found in historical texts....