Iron gall ink corrosion - the role of collection keepers

Collection keepers play an important role in the preservation of objects damaged by iron gall ink. Iron gall ink corrosion is found in both archival collections and museum collections. Despite their common problem, the difference in the amount and type of objects damaged by iron gall ink requires keepers to develop different approaches.

Introduction
There can be little doubt that iron gall ink corrosion is a serious threat to the cultural heritage of western society. The astonishing range and number of afflicted materials is conclusive evidence for anyone who might have had doubts about the seriousness of the problem. Certainly no one will deny the cultural significance of master drawings by such artists as Leonardo da Vinci, Rembrandt van Rijn, Guercino, Claude Lorrain, Eugene Delacroix, or Vincent van Gogh - just to mention the most famous names represented. But it is not only the works of the most famous artists that are endangered. An preliminary estimate shows that of all seventeenth-century Dutch drawings, at least 25% are susceptible to iron gall ink corrosion in varying degrees. If one examines the drawings of Rembrandt and his school in particular, matters are even worse. Up to 50 % of these works are drawn in iron gall ink.

Apart from the visual arts, rare and unique cultural documents are threatened. Manuscripts and music scores of such important authors and composers as Victor Hugo, Johann Sebastian Bach, Edvard Grieg, and Gustav Mahler are all written in iron gall ink. Ink corrosion is so advanced in the writings of Bach and Hugo that such priceless materials may be lost completely if an effective treatment is not developed in the near future. Of equal importance are the countless maps, architectural drawings, letters, legal documents that have been written in iron gall ink from the late middle ages to the early decades of this century. In Europe alone many kilometers of documents in archives are seriously threatened, and an estimated 80% of these are likely to be lost within the next century if the problem of ink corrosion is not addressed. Such alarming statistics are unequivocal proof that an essential part of our cultural heritage is in jeopardy.

Damage assessment
One of the first issues that all collection keepers - in archives, libraries and art museums - must address is the extent of the damage in their collections. This is not only a prerequisite for any major conservation project, but for several other important reasons as well. In the first place, a survey of this kind will aid research into the historical use of iron gall ink. When was it used and for what purposes? This information is particularly valuable in combination with a thorough survey of historic recipes for iron gall ink. One of the problems that a keeper will face in the process of making such an inventory is the lack of a standardized system to describe the damage. Furthermore, it may be difficult to distinguish iron gall ink from other historically used brown inks, even for trained paper conservators. Several institutions are currently developing a 'damage atlas' to standardize terminology used to describe different stages of corrosion, and an 'early warning system' to facilitate identification of materials at risk.

An assessment of the present damage caused by iron gall ink corrosion, in combination with an estimate of potential losses, is particularly helpful in stimulating support for research and treatment. As demonstrated by the enormous press coverage - bigger than that of many blockbuster exhibitions - of the Museum Boijmans exhibition on iron gall ink, there is great interest in the conservation of what is considered to be the core of our cultural heritage. Collection keepers should not be afraid to "use" such famous names as Bach, Da Vinci, and Van Gogh in order to increase public awareness and support for research into the problem.

Ethical questions
Even at this early stage of research it is of the utmost importance that collection keepers work together with conservators and scientists to define the aims and directions of current research. As keepers are ultimately responsible for the care of objects in their collections, interdisciplinary cooperation is especially important in addressing ethical questions that are expected to be raised during the course of research. Examples of such dilemmas are easy to find. For instance, a curator or archivist might reconsider the acquisition of works drawn or written in irongall ink as long as no preservation method exists. Even more important is the question of when, and if, a newly developed treatment should be applied to historic objects. A collection keeper may be able to provide objects of little value to researchers to experiment with in the initial stages of research, but how many years of practical research are necessary before treating a letter by William of Orange or a drawing by Delacroix? How exactly does one weigh the long term effects of a newly developed treatment against the certainty of current deterioration?

If effective treatment methods are developed in the near future, it is possible that these will be expensive and perhaps only suitable for small quantities. If so, what are the priorities? How are we going to decide which objects should be treated first, which later or which should not be treated at all? To set priorities in a well-founded manner there is again the need, as mentioned earlier, for a detailed inventory of damage in a collection.

Not the least of issues which keepers must address is the appearance of an object, which may be significantly altered after treatment. As this is a subject that fires the imagination of a much larger public - one only has to think of the discussions about the Sistine Chapel - keepers and conservators must carefully consider when an altered appearance is acceptable, and when it is not. Even so, one should keep in mind that by removing visual damage, such as blurred outlines, or by restoring colors to their original tonality, an object may be returned to a more historically authentic state. Such decisions must be supported by a curator's extensive research of the artist's techniques combined with a conservator's understanding of media and how such materials change over time.

Archives, Libraries and Museums: a different approach?
Keepers of collections with works on paper must all deal with problems concerning ink corrosion. It is therefore important that keepers of these collections - traditionally belonging to completely different networks - collaborate to address this issue. The interdisciplinary symposium at the Boijmans Museum on Iron Gall Corrosion in 1997 showed that such an approach can be highly successful. However, it is quite clear that there are different interests and priorities for keepers of art collections and archival collections. The former must address the needs of individual works whose primary importance lies in their visual qualities, whereas the latter must generally address the documentary and historic importance of papers within the context of a large archive.

There is an enormous difference in quantity of affected objects between museums and archives. Of the 15,000 drawings in the Boijmans Museum, at least 2,250 old master drawings are executed in iron-gall ink. Of this group, several hundred show signs of serious damage, while many others show lesser symptoms. Although many undisputed masterworks are seriously deteriorated, the problem is at least manageable. In contrast, large state archives often hold many linear kilometers of damaged documents. As a result, archives have a much more difficult task of setting priorities as to what should be treated first, what later, and what should not be treated at all.

On the other hand, archives are comparatively less concerned with the aesthetic appearance of works in their collection. Their first need is, at least in general, to preserve documents for use by researchers and the general public. For art curators it is essential that a drawing is preserved as a work of art, and not as a document. Keepers of print rooms thus tend to be more cautious regarding experimental treatments and will also be extremely hesitant before allowing the most precious drawings to be treated.

In the end, however, such differences are less important than the fact that all collection keepers have a common goal: the preservation of a vital part of our cultural heritage. It is therefore essential that, despite differences in interests, keepers of museum and archive collections work together with conservators, scientists, and policy-makers to develop the best solution for the problem of iron gall ink corrosion.

Dr. Manfred Sellink
Stedelijke Musea Brugge
Dijver 12
B-8000 Brugge
Belgium
T +32 50 44 8711
F +32 50 44 8737
E manfred.sellink@brugge.be