Smithsonian Institution Scholarly Press smithsonian contributions to museum conservation • number 3 Smithsonian Institution Scholarly Press New Insights into the Cleaning of Paintings Proceedings from the Cleaning 2010 International Conference Universidad Politécnica de Valencia and Museum Conservation Institute Edited by Marion F. Mecklenburg, A. Elena Charola, and Robert J. Koestler SERIES PUBLICATIONS OF THE SMITHSONIAN INSTITUTION Emphasis upon publication as a means of “diffusing knowledge” was expressed by the first Secretary of the Smithsonian. 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The Smithsonian Contributions Series are distributed via mailing lists to libraries, universities, and similar institu- tions throughout the world. Manuscripts submitted for series publication are received by the Smithsonian Institution Scholarly Press from authors with direct affilia- tion with the various Smithsonian museums or bureaus and are subject to peer review and review for compliance with manuscript preparation guidelines. General requirements for manuscript preparation are on the inside back cover of printed volumes. For detailed submissions require- ments and to review the “Manuscript Preparation and Style Guide for Authors,” visit the Submissions page at www.scholarlypress.si.edu. smithsonian contributions to museum conservation • number 3 New Insights into the Cleaning of Paintings Proceedings from the Cleaning 2010 International Conference Universidad Politécnica de Valencia and Museum Conservation Institute Edited by Marion F. Mecklenburg, A. Elena Charola, and Robert J. Koestler WASHINGTON D.C. 2013 ABSTRACT Mecklenburg, Marion F., A. Elena Charola, and Robert J. Koestler, editors. New Insights into the Cleaning of Paintings: Pro- ceedings from the Cleaning 2010 International Conference, Universidad Politécnica de Valencia and Museum Conservation Institute. Smithsonian Contributions to Museum Conservation, number 3, x + 243 pages, 142 figures, 22 tables, 2013.— The present volume brings together the papers and posters presented at the “Cleaning 2010 International—New Insights into the Cleaning of Paintings” conference that was held at the Universidad Politécnica de Valencia in Spain, in collaboration with the Smithsonian’s Museum Conservation Institute. This was the first major international conference on this topic in two decades. The 20 papers and 19 extended abstracts presented at the conference are included in this publication, grouped into four main categories: Ethics, Aesthetics, Training, and Documentation; Traditional Media: Egg Tempera and Oil; Modern Paints; and Cleaning Systems. Within each category, the papers and extended abstracts are grouped by the specific topic they address to make it easier for the reader to find all related material in one section. A summary of panel discussions held at the end of the conference has also been included. All papers and abstracts included in this publication have been peer reviewed. The aim of the conference was to provide a knowledge exchange forum and to produce a publication that assembles the latest develop- ments in the various studies addressing the problems that affect paintings. These range from normal soiling to removal of aged varnishes, from the effect of solvents on paints to the subsequent changes in their mechanical behavior. The cleaning of unvarnished paintings is one of the most critical issues that was discussed. Finally, different cleaning techniques, such as gels, soaps, enzymes, ionic liquids, and foams, as well as various dry methods and lasers, are discussed in various papers and extended abstracts. Although the conference was organized in Spain, the United States contributed 21% of the contents, fol- lowed by Spain and Italy, both with 16%; the United Kingdom and Germany, each with 9%; and Canada, the Netherlands, and Portugal, all with 5%. The rest are individual contributions from Australia, Norway, Switzerland, Poland, and Greece. Cover images, from left to right: Figure 1 from García and Marín; Figure 1 from Cremonesi; and detail of Figure 1 from Osmond and Carter. Published by SMITHSONIAN INSTITUTION SCHOLARLY PRESS P.O. Box 37012, MRC 957 Washington, D.C. 20013-7012 www.scholarlypress.si.edu Compilation copyright © 2013 Smithsonian Institution The preface and acknowledgments are in the public domain. The rights to all other text and images in this publication, includ- ing cover and interior designs, are owned either by the Smithsonian Institution, by contributing authors, or by third parties. Fair use of materials is permitted for personal, educational, or noncommercial purposes. Users must cite author and source of content, must not alter or modify copyrighted content, and must comply with all other terms or restrictions that may be applicable. Users are responsible for securing permission from a rights holder for any other use. Library of Congress Cataloging-in-Publication Data Cleaning International Conference (2010 : Valencia, Spain) New insights into the cleaning of paintings : proceedings from the Cleaning 2010 International Conference, Universidad Politecnica de Valencia and Museum Conservation Institute / edited by Marion F. Mecklenburg, A. Elena Charola, and Robert J. Koestler. pages cm. — (Smithsonian contributions to museum conservation, ISSN 1949-2359 ; number 3) Includes bibliographical references and index. 1. Painting—Cleaning—Congresses. 2. Painting—Conservation and restoration—Congresses. I. Mecklenburg, Marion F., editor of compilation. II. Charola, A. Elena, editor of compilation. III. Koestler, Robert J. (Robert John), 1950– editor of compilation. IV. Title. ND1650.C43 2012 751.6’2--dc23 2012041342 ISSN: 1949-2359 (print); 1949-2367 (online) The paper used in this publication meets the minimum requirements of the American National Standard for Per- manence of Paper for Printed Library Materials Z39.48–1992. Contents PREFACE vii ACKNOWLEDGMENTS ix ETHICS, AESTHETICS, TRAINING, AND DOCUMENTATION The Removal of Patina 1 Stephen Gritt Considerations of the Cleaning of Paintings 7 Konrad Laudenbacher The Art and Science of Cleaning Paintings 11 Stephen Hackney Surface Cleaning of Paintings and Polychrome Objects in Italy: The Last 15 Years 17 Erminio Signorini Extended Abstract—A Preliminary Investigation into the Surface Characteristics of Paint and the Implications for Restoration 23 Laurent Sozzani Extended Abstract—Noncontact and Noninvasive Monitoring of Overpaint Removal with Optical Coherence Tomography 27 Magdalena Iwanicka, Dagmara Kończalska, Piotr Targowski, and Bogumiła J. Rouba Extended Abstract—A New Documentation System: Stratographic Units Recording Sheets Applied to the Cleaning of a Fifteenth-Century Painting 31 José Manuel Barros García and Eva Pérez Marín Extended Abstract—Computer Applications and Cleaning: Teas Fractional Solubility Parameter System in Conservation 35 Amparo Saera Vila and José Manuel Barros García TRADITIONAL MEDIA: EGG TEMPERA AND OIL The Chemistry of Egg Binding Medium and Its Interactions with Organic Solvents and Water 39 Antonella Casoli, Michela Berzioli, and Paolo Cremonesi iv • SMITHSONIAN CONTRIBUTIONS to MUSEUM conservation Solvent Leaching Effects on Aged Oil Paints 45 Ken Sutherland Oil Paints: The Chemistry of Drying Oils and the Potential for Solvent Disruption 51 Charles S. Tumosa and Marion F. Mecklenburg The Influence of Pigments and Ion Migration on the Durability of Drying Oil and Alkyd Paints 59 Marion F. Mecklenburg, Charles S. Tumosa, and Edward P. Vicenzi Effects of Organic Solvents on Artists’ Oil Paint Films: Swelling 69 Alan Phenix An Evaluation of Color Change in Nineteenth-Century Grounds on Canvas upon Varnishing and Varnish Removal 77 Meredith Watson and Aviva Burnstock Extended Abstract—Oxalate-Rich Surface Layers on Paintings: Implications for Interpretation and Cleaning 85 Ken Sutherland, Beth Price, Andrew Lins, and Irma Passeri MODERN PAINTS Characterization and Stability Issues of Artists’ Alkyd Paints 89 Rebecca Ploeger and Oscar Chiantore The Nonideal Action of Binary Solvent Mixtures to Oil and Alkyd Paint: Influence of Selective Solvation and Cavitation Energy 97 Stefan Zumbühl, Ester S. B. Ferreira, Nadim C. Scherrer, and Volker Schaible Sensitivity of Oil Paint Surfaces to Aqueous and Other Solvents 107 Hannah Tempest, Aviva Burnstock, Polly Saltmarsh, and Klaas Jan van den Berg Extended Abstract—The Effect of Conductivity on Water Solubility: Cleaning a Modern Chinese Oil Painting 115 Gillian Osmond and Anne Carter Extended Abstract—Noninvasive Assessments of Cleaning Tests on an