Preface

The last three decades have witnessed major developments in conservation science. Colloids and interface science, together with materials science, which belong to the realm of popular nanosciences, have contributed concepts, techniques, expertise and tools to increase understanding of the most common degradation processes of works of art. Likewise these disciplines have provided reliable methods for durable and, as far as possible, compatible conservation.

The idea of writing a book on the application of colloid science concepts to conservation traces back to a conversation with my friend Barry Ninham, a well known scientist in the field of colloids and soft matter. He was in Florence on sabbatical leave and we were discussing the “evolution” of scientific views: “a subject or discipline is defined by a freemasonry, the members of which are united by a common lore. The received beliefs of adepts are reaffirmed by recitation and repetition of the lore, and reinforced by the weight of authority embodied in the literature of the discipline. The more venerable the literature, the more conservative is the freemasonry. Challengers to the canon are at first dismissed as heretics or apostates, but if, later, their claims are conceded to have validity, they and their theories are eventually accepted into the fold. The discipline moves on”.¹  What Barry was teaching me was what I had already experienced together with my mentor, the chemist Enzo Ferroni, when he devised the first scientific approach to the conservation of wall paintings, damaged by the Arno river flood in 1966 in Florence. His ideas gained great advantage by the strict cooperation with Dino Dini, the restorer in charge of restoration of the Beato Angelico*s frescoes in San Marco Basilica. The rigorous approach of Ferroni*s method was barely accepted among the restorers in Florence at that time, when most of the restoration interventions (and not only in Italy) relied on the use of polymers, which were later proven to be harmful for the paintings. I continued working, with Ferroni, on the development of the Ferroni method during the restoration of Beato Angelico in San Marco and on the development of new methods for conservation; a few years later, Luigi Dei joined us. Restoration was indeed a fascinating field, but it was at the border of official science, so we worked on the subject in our spare time. It was a sort of hobby, exciting, but something that was not useful for an academic career or to improve our bibliometric indicators, not to mention funding. However, working in the historical center of Florence was an inexhaustible source of inspiration and motivated us to continue working in that field.

I was convinced that this research subject was not interesting to “real scientists”. In 1998 Jean Marc di Meglio, a friend of mine working with Pierre Gilles de Gennes at College de France, asked me to give a speech at the meeting in Les Houches celebrating the 65^th birthday of Pierre Gilles. That was the first speech I gave to scientists on conservation and, to my surprise, it attracted a certain interest in the audience. However the field was not yet mature; a few years later, Barry*s idea of writing a book on “our” new methods for conservation failed miserably when a famous publisher considered the subject too interdisciplinary to be worthy of publication.

Since the Florence flood, conservation science has developed along two main lines: 1) the use of advanced diagnostic techniques for the study of artworks; 2) the production of innovative materials and methods for the cleaning, consolidation and protection of different artistic objects. The authors of this book, through their research work, have mainly contributed to the second area.

This book is intended to provide the reader with the basic concepts of colloid and interface science that have constituted our scientific background to deal properly with conservation issues, and builds on our research experience and active experimentation in colloids and surface science, fuelled by continuous exchanges and feedback with end-users belonging to the restoration community, such as freelance restorers, private and public conservation institutions, and museums.

There are several books dealing with conservation, but there is a lack of a unique treatise showing the potential, and in most cases real, impact of nanosystems to restoration. The main idea behind this book is indeed to fill the gap between the traditional restoration methodologies that are based on “classical chemistry”, and the most recent methods that benefit from the cultural framework of colloids and material science. In this sense, this book is unique in providing detailed information on how to produce and to use advanced systems for conservation. In fact, in the last few years we have been solicited by several colleagues to write a theoretical and practical textbook on this subject. We are therefore grateful to RSC for giving us this possibility.

We have selected material from several Masters and PhD courses, held by the editors and authors of this book, in the Conservation program of the Faculty of Science of the University of Florence, to create and shape the chapters reported in this book, always taking into account the point of view of restorers and end-users.

Writing such a treatise was not a straightforward task. The most insidious risk was to emphasize the theoretical aspects of colloids science over the conservation applications, or vice versa, weakening the fundamental message that we wish to deliver, i.e. that the union of a strong expertise in colloids and material science with the practical knowledge derived from the restorers* needs is fundamental to developing innovative and effective methods that are compatible with the properties of the works of art to be preserved, to grant long-term preservation of cultural heritage.

Several sections of this book are indeed conceived as practical tools to guide conservators and restorers through the production and application of nanomaterials for the conservation of works of art. Real case studies are approached and discussed, where the use of nanoparticles and other systems belonging to the colloidal domain has proven fundamental and innovative with respect to traditional restoration techniques.

Besides conservators and restoration end-users, the audience for which this book is of interest includes both academic scientists who approach the subject of conservation science for the first time, and advanced undergraduate or postgraduate students. In this sense, this treatise can be used as a textbook for teaching or as a reference and inspiration for further research work in this challenging and exciting field. In particular, students will find the “Review and Questions” sections beneficial in order to ensure full comprehension of the treated topics and to stimulate discussion of the most crucial aspects. On the other hand, curiosity-driven scientists, who wish to get involved in this emerging field, will find a widely interdisciplinary scientific background, different from conventional conservation science, which exhibits a strong overlap between the different “Science” and “Humanities” ways of thinking.

This book is organized in chapters that provide the cultural background for the comprehension of the systems that are used in most of the interventions for the conservation of both movable and immovable works of art, and others that highlight the application of innovative systems to real conservation case studies.

Some recommendations are necessary for conservators that are particularly interested in the applicative and case study sections, which cover the most common conservation interventions. A warning message that we want to transfer is that most of the innovative formulations (especially those for cleaning) are based on self-assembling systems, meaning that any modification to their composition possibly leads to a dramatic change in the physico-chemical properties (and effectiveness) of these systems. If conservators really want to modify such systems the best approach, we suggest, is an interactive cooperation with scientists who are expert in the field of colloids and materials science in order to maximize the effectiveness of the adopted nanostructured systems. This would also produce a progressive refinement of the involved technology and the tuning of the proposed systems to address specific conservation issues. In one word, cooperation is the key.

As a final, but most important note, I would like to express my deep gratitude to David Chelazzi, who shares the editing of this book and has carried an impressive burden on his shoulders.

Together with David, I would like sincerely to thank all the authors with whom we are in debt for the realisation of this work. A special thanks to Pierandrea Lo Nostro for his invaluable criticism and constant support, through this intense writing experience. We also wish to thank all the conservators who indirectly contributed to the refinement of the conservation methods we developed. Finally, we wish to acknowledge both the European Union (which has financed the “Nanoforart” FP 7 project) and CSGI (Consorzio Interuniversitario per lo Sviluppo dei Sistemi a Grande Interfase - Center for Colloid and Surface Science), which is the main source of funding and the driving force of this “side activity”, for financial support.

Piero Baglioni