Phytate - The Huygens casestudy
Birgit Reissland, Karin Scheper and Sabine Fleischer (2007)
The chapter starts with a introduction into the conservation project of the Christiaan Huygens manuscript-collection at the University Library of Leiden. During this project, the paper conservators experienced the everyday difficulties of decision making regarding treatment of ink-corroded artefacts. Occurring problems and hands-on experiences that were obtained during this project lead to the idea of writing this chapter. It is hoped that this initiative will save time and prevent trouble for those paper conservators who intend to apply the calcium-phytate / calcium-bicarbonate method.
Anticipated increase of use - a reason for treatment
A few months before his death the world famous Dutch mathematician and physicist Christiaan Huygens bequeathed his scientific papers to the University of Leiden, the institution in which he had studied from 1645 to 1647. In the 19th century the Leiden ‘Codices Hugeniorum’ were extensively enlarged by the donation and acquisition of manuscripts from family possessions. In 1882 the Royal Netherlands Academy of Science (KNAW) started a publication project of the works of Christiaan Huygens, inventor of the pendulum clock and discoverer of light as undulation. A team of editors worked over 65 years on the 22 volumes ‘Oeuvres completes’. With this edition, large parts of Huygens’ unpublished writings (workbooks, drafts, loose sheets and letters) became available in print, but not all of them. Despite many being available in print, the originals continued to be frequently used, since the 'Oeuvres complètes' actually are not as complete as their title implies. Furthermore, the editors published the texts according to their own subject arrangements. The American scientist Dr. J. Yoder is currently completing a detailed catalogue of all Huygens papers which will improve the accessibility and probably enhance the use of the ‘Codices Hugeniorum’. Since only 10 % of the collection is accessible as microfilms, the original manuscripts are to be studied by the scholars instead. The anticipated increase of use conflicts with the condition of the manuscripts. After more than three centuries, the papers show evidence of intensive use. Because of Huygens’ habit to write through into the margins, every damaged edge of paper presented a risk for loss of content.
Initiation of a conservation project
For that reason, in 2002 a condition survey was carried out for the entire collection. Based on its results, a subsidy was granted by the Stichting Academisch Erfgoed in 2003, from which a three year conservation project could start. Since neither digitalization nor microfilming was included in the grant, the aim of the conservation was to guarantee the access to the collection by stabilizing the damaged artefacts.
General condition of the collection
The conservation of the papers consisted for a major part of the repair of the dirty and damaged curling edges, partly caused by inadequate storage in portfolios that were to small. Nearly all of the text is written in iron gall ink which in many cases is quite stable and does not or hardly causes paper degradation. Some papers, however, are damaged by ink corrosion. Sometimes it occurs on drawings that illustrate text or belong to calculations. Drawn circles or triangles are in danger of falling out of the paper.
Which treatment is appropriate?
These areas required a repair with Japanese paper and starch or gelatine. Both adhesives are based on water as a solvent. The moisture introduced by the adhesive bears the risk to transport corrosive ions and acids, worsening the condition of the paper. Therefore a combined calcium-phytate / calcium-bicarbonate treatment was chosen to inactivate detrimental compounds and to prevent ink corrosion. Applying this relatively new treatment involves certain risks. These risks and the long term effects on real objects are not yet fully known, but several international studies confirm the positive influence of calcium-phytate on ink corroded manuscripts (Kolar et al. 2005, Zappala and de Stefani 2005, Botti et al. 2005, Kolbe 2004, Hofmann et al 2004, Simbürger et al. 2004, Neevel 2000, Reissland and de Groot 1999). The calcium-phytate treatment was applied on loose sheets and letters only because it is a wet treatment. Bound textbooks were not disbound and therefore the pages are not treated as yet.
Initial treatment - what had gone wrong?
An initial treatment was carried out on the basis of the recipe and instructions from a workshop ‘Iron gall ink treatment’ held at the Netherlands Institute for Cultural Heritage (ICN, Amsterdam) in 1998. In actual practice, however, many questions arose. The first results were not entirely satisfying. Several unexpected side effects such as the formation of cracks and loss of substance occurred within original manuscripts. Both the conservator and the collection keeper regarded them as unacceptable. What had gone wrong? Could one prevent these side effects?
It was decided to carry out a second test together with the ICN, in order to survey and document treatment-related problems and to implement procedures to avoid their side effects. The group agreed that the results should be made accessible to the field of paper conservation in general, therefore an internet – publication has been chosen.
The assessment for treatment and the carrying out of the treatment will of course differ from collection to collection and conservation workshop to conservation workshop. The same goes for making the selection of the objects that are to be treated, as many factors play a role in that decision-making process. We tried to account for the decisions made during this project as clearly as possible.