Varnishes and Surface Coatings: Introduction

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The information presented on the Paintings Conservation Wiki is the opinion of the contributors and does not imply endorsement or approval, or recommendation of any treatments, methods, or techniques described.

Author: Sarah L. Fisher
Date: Submitted August, 1997
Compiler: Wendy Samet

Introduction to the "Painting Conservation Catalog"

The Painting Conservation Catalog is a collective volunteer project of the Paintings Specialty Group of the American Institute for Conservation of Historic and Artistic Works (AIC). In order to address the need for literature in the field, the AIC board has mandated that the specialty groups record their bodies of knowledge—the collection of techniques and information which make up their expertise. The purpose of the Catalog is to record information about a variety of materials and treatments in current use or with a history of use in painting conservation, to serve as a convenient reference for practitioners in the field. An attempt has been made to include a broad range of these materials and techniques and divergent opinions about them. The Catalog is designed for the practicing painting conservator and is not intended to establish definitive procedures nor to provide step-by-step recipes for the untrained. It is understood that the individual conservator is solely responsible for determining the safety and adequacy of a treatment for a given project and must understand the effect of his or her treatment. Inclusion of a specific material or treatment in the Catalog does not constitute endorsement or approval.

The Catalog project has been developed following the advice and experience of the AIC Book and Paper Specialty Group's Paper Conservation Catalog editorial board, with many thanks to Kate Maynor and other paper conservators for their insights. The Project Director for the Painting Conservation Catalog was chosen by the Painting Specialty Group at the Denver AIC Annual Meeting in 1993. The Project Director in turn chose the eight-member editorial board which has responsibility for production of the Catalog. The board sets policies and procedures for the project, schedules production, develops the chapter topics and general chapter outline, chooses chapter compilers, and edits drafts of the chapter entries for content. The eight-member board and project director meet regularly in the greater Washington, D.C. area.

Each chapter is put together by the compiler who controls and shapes it according to his/her concepts. One editorial board member serves as board liaison to the compiler, facilitating communication between the board and the compiler. Occasionally a board member also serves as chapter compiler, as is the case with the first chapter on varnishes and surface coatings. The chapter compiler and the editorial board work together to find the contributors. The contributors write the individual entries that comprise the chapter and are responsible for the information within those entries. Peer review has been provided by four outside readers for the first chapter, and the editorial board plans to continue the policy of peer review for coming chapters. A copy editor edits and helps organize the chapters and creates the cumulative bibliography and other appendices.

Due to its size, the present chapter is published here as the first full volume of the Painting Conservation Catalog. The editorial board plans to publish future volumes comprised of two or three chapters. However, the first chapter proved to be so long that it became a volume in itself. The planned order of production of chapters follows no specific sequence other than that dictated by the interest of a compiler. Chapters in process include “Stretchers, Strainers and Mounting,” Barbara A. Buckley Compiler, “Inpainting,” Jim Bernstein, Compiler.

In its first year of publication, each volume of the catalog will be distributed free of charge to Paintings Specialty Group members in good standing, and it will be made available to other AIC members for a lower fee and to non-members for a higher fee. In subsequent years, the volumes will be available to all for a fee, lower to AIC members and higher to non-members.

The Catalog chapter is provided in a looseleaf binder. The board envisions this as a flexible tool, convenient for studio use, with space for notations, additions to entries, and with pages easily removable to use at a work site. The board has had long discussions about this format and is interested in readers' opinions. The informal format is meant to encourage further notations of tips, workshop hints, and recipes which otherwise might not be passed on.

The Catalog project hopes to be as inclusive as possible, to encourage participation from many painting conservators in order to encompass a great variety of treatments, techniques, and approaches. The compilers and editorial board strive to include a representative cross section of materials and techniques while excluding those proven unwise. Materials and techniques which may have been historically important but are rarely in use may be included if they are commonly found on paintings. Anyone who has been in the conservation field for any length of time has seen fashions in materials and techniques come and go. Each new approach is claimed to be “more scientific,” “more artistic,” “less invasive,” or “truer to the artist's intent” than the last, and similar claims are made for each new material. However, the field has made enormous strides since the 19th century in building a factual and historical basis from which to assess new developments. The Catalog project will contribute to that foundation in articulating some of the practical information extant in the profession.

Introduction to Volume 1 Varnishes and Surface Coatings

The Painting Conservation Catalog editorial board chose varnishes as the subject for the first chapter because of their topicality. We wanted a materials-based chapter on a topic where current information is changing rapidly and convenient reference material is regularly needed. The task has proven more complex than expected: new research is constantly contributing new materials and ideas to the field and making earlier varnishing materials obsolete, and the aesthetics of varnishing is subjective and a difficult topic to organize.

The purpose of this chapter is to present materials and methods of varnishing used in painting conservation. Included are some considerations of the history of use and the factors attending the decision whether to varnish and, if so, with what and how. The chapter also provides a bibliography of related literature.

The chapter focuses on North American varnishing traditions and practices. European practice is referred to as needed and its profound influence is recognized but in no way systematically reviewed. The practices discussed are applicable only to easel paintings in the Western tradition with some reference to Western mural paintings; other cultural traditions are not addressed.

Each entry within this chapter can be used independently. Each has been printed so that it can be removed from the notebook and has an informative page format with the names of author(s) and the entry submission date on each page. The references are listed at the end of each entry and there is a cumulative bibliography at the end of the chapter. There may be repetition of information from entry to entry: this policy was followed in large part so that individual entries could stand alone.

The outline format for the individual varnish/resin entries was given to the contributors by the editorial board, although not all entries could be adapted to it. The choice of varnishes included in the chapter represents the board's considered decisions as to those which would be most useful. Many historical varnishes are not included. The inclusion of commercial varnishes was fraught with peril. Many are commonly used by conservators but may not be recommended for conservation use. Manufacturers' testing methods are not as rigorous as those of conservation scientists. The editorial board made a conscious decision that entries on proprietary varnishes should be brief to reflect the lack of independent comparative testing. Proprietary varnishes can best be evaluated by reading about each of their component resins. Manufacturers understandably often refused to divulge the exact contents of their varnishes. We well know that the contents can change from batch to batch and year to year, and that any specific information provided here may be obsolete before the print is dry.

The scientific data requested from each contributor was designed to include only reproducible, consistent data, thus avoiding the perils of varying test conditions and methodologies. The process of editing the scientific information pointed out the difficulties of summarizing and comparing complex scientific data and literature. An attempt was made to present a simple review of the information as clearly as possible. In many cases the reader is directed to the literature on the subject. Another editorial problem was varnish measurements: conservators traditionally have stated the proportion of resin to solvent as a percentage of a whole, which is scientifically inaccurate. The board, wherever possible, imposed a weight-to-volume measurement on the varnish recipes in the hope that such consistency would make the information more comparable. The Health and Safety sections at the end of the varnish entries are summaries of OSHA Material Safety Data Sheets and are meant to serve as a quick reminder of their information rather than a replacement for them.

The compiler and editorial board have tried not to fit each entry into a mold. In addition, each entry is the product of its author and the board has not checked every fact presented. The references have been checked by the copy editor for accuracy of titles, page numbers, dates, etc. but not by the board for content. Questions on the information presented should be directed to the contributor. The editorial board recognizes that successful varnishing is a product of years of practical experience and hopes that this chapter will be a useful aid in the accumulation of that experience.

Acknowledgements

The project has been funded in major part with a grant from the Samuel H. Kress Foundation and also by the AIC Paintings Specialty Group. The editorial board and the Paintings Specialty Group are deeply appreciative of the support of the Kress Foundation and its understanding of the need to record the treatment practices of the painting conservation field.

My most heartfelt thanks go to Wendy Samet, the compiler of this chapter, and to the editorial board, Barbara A. Buckley, Sian Jones, Cathy Metzger, Peter Nelsen, Mary Sebera, Jane T. Sherman, and Jill Whitten. Wendy's enthusiasm, creativity, hard work, and professionalism were essential in forming the chapter's contents, encouraging contributors, and getting the chapter through difficult moments. The board's cheerful donation of its time, reliable contribution of entries, new ideas and insights, and steady attendance at meetings has made work on the catalog a pleasure. Special thanks go to Jill Whitten for her numerous contributions.

We all acknowledge the great dedication of our contributors and thank them for their hard work, dedication, and flexibility which have made the project possible. The wise advisors we would like to thank include Jim Bernstein, Bob Feller, Mark Leonard, Chris Maines, Diane Dwyer Modestini, Steve Prins, and René de la Rie. We thank the many other conservators, too numerous to list, for their help on the project. And thanks must go to the manufacturers' representatives who have patiently put up with all our questions about their products and contributed much important information. Many thanks to the AIC office staff, especially Sarah Rosenberg, former AIC executive director, for advice and support. And warmest appreciation goes to our editor, Jessica Brown, whose unfailing cheerfulness, attention to detail, and advice have helped pull the project together.

Sarah L. Fisher
Project Director
August, 1997

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