Dr. Christine Seidel | 12.06.2014 | 9549 Aufrufe | Artikel

Secrets of medieval manuscript illumination

Notes on the study day Inside Illuminations – Art Technical Research & The Illuminated Manuscript (June 5th, 2014, Brussels, KIK-IRPA)

Art technical research on works of art has been a major field of interest for more several decades now. It was first and foremost pursued by conservators and used for object-based analysis carried out in the curatorial departments of museums all around the world. The first interdisciplinary studies in the field of panel painting such as the conference series Le dessin sous-jacent dans la peinture, which was first held in 1977, have brought attention to new methods and questions of research. Investigation techniques such as X-radiography, infrared reflectography and various methods of pigment analysis and molecular identification belong to the standard procedures of painting examination and are also used by curators in modern museums today. The increasing knowledge about material properties is considerable and can help in many ways not only to determine the condition of a work of art but also to better understand aspects of its creation, its alteration throughout time and the artists’ working methods. The interest in the technical study of illuminated manuscripts has long been neglected outside the conservation studios and, for a long time, was only rarely a point of interdisciplinary discussion between conservators and art historians.

Marina Van Bos (KIK-IRPA), Lieve Watteeuw (Illuminare) and Anne Dubois (KU Leuven & UCL) organized the study day held at the KIK-IRPA in Brussels, which turned into such a large success that it could have well filled a much broader conference program. The wide attendance of both manuscripts conservators, art historians and students has proven that the subject did not only touch questions of general relevance for all the disciplines but also revealed the need for a broader and more accessible presentation of methodologies and appropriate means of communication between science and humanities to fruitfully link both specialties.

The first part of the morning session was opened by the curator Stella Panayotova and her scientific research collaborator Paola Ricciardi, both of the Fitzwilliam Museum, who presented their research on the Grandes Heures of the duke Philip the Bold (ms. 3-1954). The study is part of the larger research project MINIARE, dedicated to the technical analysis of illuminated manuscripts at the University of Cambridge; its results will be presented to a broader public in a large exhibition at the Fitzwilliam Museum in 2016. Both presenters used the results of their non-invasive technical examinations – infrared reflectography (IRR) to investigate the underdrawing, UV reflectance spectroscopy and X-ray fluorescence (XRF) for pigment identification – to better differentiate technical properties and ultimately to find new arguments to support the attribution of the miniatures to different masters already established by art historians. Panayotova (“Inside the Grandes Heures of Philip the Bold. The Parisian Campaign of Illumination. Part I: The Artists”) presented the art historical characterization of the painters of the first campaign of illumination, executed between 1376-79 by the Master of the Bible of Jean the Sy and the Master of the Coronation Book of Charles V, and showed in what areas technical investigation could clarify the circumstances. Ricciardi (“Part II: The Materials”) presented the results of numerous non-invasive examination techniques including the identification of pigments used by the two painters to underline the art historical evaluation presented by her colleague. Especially the new findings concerning the underdrawing will be of enormous benefit for the art historical study of illuminated manuscripts, since there is so little known about this subject matter. On very informative outcome of the subsequent questioning included a discussion about the components of iron gall ink, which frequently seems to have been used for preparatory drawings in illuminated manuscripts, and their visibility in IRR. The experts agreed that – depending on the type of pigments used in the color layers and the range of reflected light through the use of band pass filters – other, non carbon-based drawing materials such as iron gall ink could also be made more visible.

The very efficient XRF analysis was also the topic of Nancy Turner’s (Getty Conservation Institute) paper. The newest development in this technique is the so-called Macro-XRF analysis that does not detect chemical elements in a particular spot but scans an entire surface and can subsequently map out the distribution of elements throughout the entire surface. The group of developers from the Universities of Antwerp and Ghent first presented the rather large machinery developed for the analysis of panel painting on the Amsterdam conference Painting Techniques (18-20 September 2013). It subsequently traveled to several North America and was used by the Getty to test its use for the analysis of manuscript leaves (the save use of books with the machinery that takes several hours to scan larger surfaces has not been figured out yet). Turner demonstrated the advantages of XRF-mapping especially in the evaluation of working procedures and restorations since it can also detect elements that are not in the surface layers and furnishes much clearer images of their distribution than X-radiography or infrared-reflectography. In contrast to the point analysis, the macro-XRF scanning has the advantage of showing the elemental occurrence in the context of its distribution throughout the painted area. Her paper made clear that especially in terms of the identification of later additions and repaintings, the macro-XRF scanning might be a powerful and efficient tool with numerous benefits for large collections.

The second session started with a paper by Lieve Watteeuw (Illuminare) and Marina Van Bos (KIK-IRPA) (“Inside an early 14th century Franciscan Antiphonary. Documentation and Analyses of a Flemish Choir book”), who presented a new mapping technique to display the surface properties of medieval manuscript leaves, which was developed in the ongoing RICH project (Reflectance imaging for Cultural Heritage). The so-called RTI (reflection documentation imaging) is based on polynomial texture mapping and creates a multidimensional image of the parchment surface under different light conditions. Distortions, losses and exact measures can thus be made more clearly visible. It is carried out with a hemispherical structure equipped with a video camera that captures images of the surface while the object is lit from different angles. The 14th century Franciscan Choir book made in the Ghent-Bruges area (its present location unfortunately escaped my attention), which was the subject of investigation, was also examined by means of XRF and µRaman for molecular and pigment identification that allowed a comparison with already collected data recuperated from manuscripts produced in the area. An interesting phenomenon was touched in the discussion: the interesting use of both gold and silver leaf lead to interesting observations of the still little-studied silver degradation in illuminated manuscripts. In the case of the Antiphonary, the combination with gold might have had an effect on the subsequent and probably very quickly advancing “silver bleeding”.

Robert Fuchs and Doris Oltrogge (Cologne Institute for Conservation Sciences and department heads of the only degree course for the conservation of works on paper and illuminated manuscripts in Germany), who started their interdisciplinary research project on the techniques of medieval manuscript illumination in 1984 and are among the most accomplished researchers in the field, began their paper with an overview over the methods applied in their long-term research projects, among them the use of band pass filters for infrared cameras that allow, through shorter intervals of wavelengths, a more narrow focus on particular aspects that are to be explored. In a second step they outlined relevant questions that could be clarified by the application of various methods of technical analysis. These were applied to the production of Ottonian manuscripts made on the Isle of Reichenau, with a particular focus on workshop practices and the partition of work (“The Dream of Nebukadnezar. Painting of the Ottonian Reichenau scriptorium”). Of particular interest were the different gilding techniques and the use of ground metal particles in pigments that were examined in a number of manuscripts conserved at the state library in Bamberg. Brass-based gilding for example is a particularity that never occurs in the Reichenau workshop; thus its occurrence in the 10th century Isaias glossatus (msc. bibl. 76) is a strong indication of a collaborating artist who only worked for a very brief period of time with the scriptorium. The use of ground metals and metallic glazes, as well as colored glazes on metal leaves was another particularity that the two scholars could point out with precision and successfully integrate into their argumentation of different participating painters in an otherwise homogenous production.

The last and longest session began with Anne Dubois’ (UCL, Louvain-la-Neuve) paper on the Brussels Fleur des histoires (“Some technical notes on the Fleur des histoires (Brussels, KBR, ms. 9231-9232) by the Mansel Master, the Thérouanne Master and Simon Marmion”). Not only did she present an excellent codicological analysis of the two volumes, finding very good arguments not only for the use of an iconographic reference system after which the illuminations were made, but based on these indications also could draw conclusions about the stages of their execution. Aided by photomicrography and the benefits of its high-resolution magnification, she presented a sharp division of hands and connected them to the workshop of Marmion. One very immediate benefit of the use of photomicrography in the study of illuminated manuscripts is without a doubt the possibility to visualize detailed variations in painting technique and the handling of paint that usually can only be studied in the original. Although high-magnification images are no substitute to the study of the original and also have the tendency to suppress the overall effect that ultimately forms the idea of an individual artistic character, they could become extremely helpful in communicating observations like brushwork, alterations, pentimenti and the partition of work in one miniature in later medieval manuscript illumination that were previously mostly limited to the descriptive qualities of the scholar.

The three subsequent presentations focused on the benefits and results of technical examination of entire collections: Maria João Melo and Adelaide Miranda (Institute of Conservation and Restoration and Institute of Medieval Studies, University of Lisboa) presented their agenda in the conservation of illuminated manuscripts in Portuguese collections in order to understand degradation processes of pigments and to develop more precise methods of conservation (“Colour in medieval Portuguese manuscripts: between beauty and meaning”). The Romanesque manuscripts from the scriptoria of Lorvão, Santa Cruz and Alcobaça were studied and generated a large amount of reference data. The properties of the binding medium, which can only be properly analyzed with the help of paint samples (a mixture of egg white and parchment glue was identified in the examined manuscripts), plays an important role in the modern-day color appearance and the halting of degradation processes that are not only a consequence of particular chemical properties of a pigment but can also be caused by combination with others, such as orpiment that can have devastating irreversible effects on the chemical stability of neighboring colors.

The British Library uses diverse non-invasive measuring techniques such as digital microscopy, multispectral imaging and visible reflectance spectroscopy to measure and characterize existing damage and the condition of manuscripts in their more recent history. This is an efficient method to verify whether changes have occurred for example after times of exhibition these objects. Christina Duffy, Paul Garside and M. Beltran de Guevara (London, British Library) presented the case of the famous Lindisfarne Gospels (MS Cotton Nero D IV), a pinnacle of 7th century Anglo-Saxon manuscript illumination, which was recently exhibited at the Cathedral Library of Durham (1 July – 30 September 2013) and attracted a large number of visitors that used the opportunity to see the spectacular manuscript (“Monitoring Pigment Stability in the Illuminated Treasures of the British Library”). Especially the pigment stability with the presence of orpiment and fugitive red and yellow lakes are a concern of the conservators, as well as crack patterns throughout the color layers, which they call micro-fracturing of the paint. This allows the identification of areas of particular concern and an exact measurement of thinkable alterations, leading ideally to optimized conservation measures and display methods in future exhibitions. Following this intense study illustrated with beautiful photomicrographic documentation it was a reassuring conclusion to hear that the display of the Lindisfarne gospels last year did not cause any measurable change to the pigment structure or the painted surface of this precious manuscript.

The last paper presented by Aurélie Mounier (Bordeaux University) focused on the technical study of the manuscript leaves in the treasury of the Cathedral of Bordeaux (“Multidisciplinary study of medieval illuminations of the Marcadé Collection (Treasury of Saint-André Cathedral of Bordeaux, France)”). A set of forty-two manuscript leaves dating from the 13th to the 16th century, of French, Italian, Spanish, German and Flemish origin, was given to the cathedral in 1947. The miniatures were studied with hyperspectral imaging and fluorescence spectroscopy, assigning a particular reflectance spectrum to the pigments that are then identified by comparison to existing spectra in a reference database but are only conclusive for few pigments. This necessitates complimentary methods, such as XRF and Raman spectroscopy. It is however a non-invasive technique that can in certain instances help to develop further questions on the nature of organic components.

The different presentations gave a representative and very promising overview over the latest developments in analytical methods and the ongoing projects of the leading researchers in the field. It was only fitting that an art historian, Catherine Reynolds, was asked to close the day with some final remarks. It is a very positive signal for the future of art technical research that most of the projects were the result of a collaborative work between scientists and art historians and are conducted in important manuscript collections, such as the Fitzwilliam Museum, the British Library, the J. Paul Getty Museum and the State Library of Bamberg. Even though certain analytical methods and results do not seem to have an immediate effect on the work of an art historian for now, common themes of interest emerged in the discussion, such as the composition of inks, the use of metals in various forms and the diversity of the underdrawing, both in terms of identifying the materials and the possibility to make them visible. The more intense study of working techniques that have always occupied historians of the book will certainly benefit from these new analytical techniques and – this might be one of the most important aspects – can be made visible, and opened for new methodological approaches.

There can be no uncritical acceptance of technical tools that often create an abstract image of results that need to be interpreted by the researcher and thus always only show a variant or fragmented aspect of an entity. They will also not be the key factor in helping us to better understand the work of art as such, nor will their use in the understanding of material properties replace the interpretation through the trained eye of a connoisseur. But in an art historical perspective these promising techniques will certainly help to better name the reasons for particular appearances and conditions, to develop new questions concerning the working process, to explore underdrawings that are such a crucial part in the creative process, and – this might be the most promising aspect for a struggling academic discipline – to return to the uncompromised appreciation of the objects and the visual and artistic properties themselves.

A (very) short selection of interdisciplinary technical studies of illuminated manuscripts (assembled by an art historian, with no claims of being complete):

Anne H. van Buren, “Problems and Possibilities of the Reflectography of Manuscripts. The Case of the Turin-Milan Hours”, in Le dessin sous-jacent et la technologie dans la peinture. Perspectives, ed. by Roger van Schoute and Hélène Verougstraete, Louvain-la-Neuve, 1997, pp. 19-28.

Marigene H. Butler and J. R. J. van Asperen de Boer, “The Examination of the Turin-Milan Hours with Infrared Reflectography: A preliminary Report”, in Le dessin sous-jacent dans la peinture. Colloque VII: Géographie et chronologie du dessin sous-jacent, ed. by Roger van Schoute and Hélène Verougstraete, Louvain-la-Neuve, 1989, pp. 71-76.

Ezio Buzzegoli, Diane Kunzelman, Duilio Bertrani et al., “Methods and Results of Non-Invasive Testing: Infrared Reflectography and False Colour”, in Heures de Turin-Milan. Inv. n° 47. Museo Civico d’Arte Antica, Torino. Commentary, ed. by Anne H. van Buren, James H. Marrow and Silvana Pettenati, Lucerne, 1996, pp. 209-216.

Brigitte Dekeyzer, “The Mayer van den Bergh Breviary (Ghent-Bruges, early 16th century“, in La peinture dans les Pays-Bas au 16e siècles, ed. by Hélène Verougstraete and Roger Van Schoute, Louvain-la-Neuve, 1999, pp. 303-316.

Anne Dubois, “The Donne Hours. A codicological puzzle”, in Journal of Historians of Netherlandish Art, 6.2014,1.

Robert Fuchs and Doris Oltrogge, Die Maltechnik des Codex Aureus aus Echternach. Ein Meisterwerk im Wandel (Wissenschaftliche Beibände zum Anzeiger des Germanischen Nationalmuseums, 27). Nuremberg, 2009.

Robert Fuchs, Oliver Hahn and Doris Oltrogge, “Konzeption und Ausführung: Maltechnische Untersuchungen des Stundenbuches”, in Das Stundenbuch der Sophia van Bylant, ed. by Rainer Budde, Roland Krischel, Cologne, 2001, pp. 97-118.

Robert Fuchs and Doris Oltrogge, “Painting materials and painting technique in the Book of Kells”, in The Book of Kells. Proceedings of a Conference at Trinity College Dublin, September 1992, ed. by F. O‘Mahonny, Aldershot, 1993, pp. 133-171.

Doris Oltrogge, “Zerfallen – nicht lesbar – nicht sichtbar. Die Bandpassfilter-Reflektographie als Hilfsmittel der Handschriftenkunde”, in Totenbuch-Forschungen. Gesammelte Beiträge des 2. Internationalen Totenbuch- Symposiums (Studien zum Altagyptischen Totenbuch 11), ed. by Burkhard Backes, Irmtraud Munro and Simone Stohr, Wiesbaden, 2006, pp. 273-282.

Nancy Turner, “The suggestive brush. Painting techniques in Flemish manuscripts from the collections of the J. Paul Getty Museum and the Huntington Library“, in Flemish Manuscript Painting in Context. Recent Research, ed. by Elizabeth Morrison and Thomas Kren, Los Angeles, 2006, pp. 57-74.

Lieve Watteeuw (Ed.), The Anjou Bible. A Royal Manuscript Revealed: Naples 1340, Leuven, 2010.

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Seeing the world of an artist through a lense: different mixtures of blue pigments and powdered gold mixed with a binder applied as highlights in a medieval illumination

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