Teresa Espejo Arias, University of Granada and L. Crespo Arcá, National Library of Spain

The paper will be presented by Tania Estrada.

The Experience of matting single parchment documents for exhibition: The case of the 'Capitulaciones de Almería'

Technical and scientific publications provide an excellent means of supporting the on-going learning process of conservators. Such publications provide an insight into the techniques, materials and tools that help ensure that professionals who cannot attend workshops or other kinds of training in person can benefit from continual development. Those processes that are scientifically quantifiable are relatively easy to apply without the presence of the specialist who devised them. By contrast, there are other processes that appear easy to apply but that in reality are extraordinarily difficult as, in addition to knowledge of the techniques and materials, they require the practitioner to access their intuition and sensitivity – a skill that cannot be acquired by reading a book. In such scenarios there is a process of trial-and-error at play, during which erroneous conclusions can be drawn or the practitioner may even give up, particularly if they lack the necessary patience and expertise with which to understand all of the variables involved. One such example is the difficulty of mounting parchments securely, either for temporary exhibitions or for longer-term housing – a challenge that conservators are often faced with.

The special nature of parchment requires an understanding of its behaviour, which cannot be achieved without extensive knowledge of its physical and chemical characteristics and the processes by which it is made. Due to its extreme sensitivity to changes in temperature and humidity, parchment often reacts unexpectedly, becoming distorted or warped – phenomena that conservators sometimes address with aggressive interventions that may affect the very nature of the document. Our experience of dealing with this material has led us to affirm (and bring up to date) the matting system that was developed and explained in the 1980s by C. Clarkson, based on the stretching system used for drying the skin when the parchment was first produced. Either for aesthetic reasons or due to the difficulties it presents, this system has not been as widely used as it deserves, despite the fact that it has been found to be ideal for matting parchments. As such, it was the treatment of choice selected for our intervention on the document under study, namely the Capitulaciones de Almería.

Capitulaciones de Almería is the name given to the document that, in 1490, ratified the treaty between the Catholic Kings and El Zagal, the Sultan of Granada, to hand over the city of Almeria to the Catholic Kings in the latter days of the Reconquista on the Iberian Peninsula. This document, written with black ink on a bifolio parchment, is conserved at the Archive of the Royal Chancellery of Granada, having been deposited there as documentary evidence in a trial of law. Among the principal damage we found was loss of the support around the edges and other localized sites, due to severe humidity. The action of the water had prompted a biological reaction, leaving the edges of the document extremely fragile and hygroscopic. The piece also presented cracks, tears, creases, distortions and, overall, accumulated dirt.

Given the need to restore the parchment and display it accordingly (that is, vertically and visible from both sides), we undertook a review of the different matting systems that could be used for this kind of document. The present work captures the criteria applied and the procedures carried out as part of the research in question, and outlines the different aspects we believe have influenced in the non-generalization of the procedure despite its effectiveness having been proved. On the basis of previous experience of applying the proposed system on other documents, and in line with the method developed by C. Clarkson, the system involves attaching the parchment to a cardboard window or passe partout by means of linen threads fixed with wheat starch to the skin. This approach ensured that the threads would respond perfectly well to any environmental variations and thus avoid any unexpected distortions or alterations to the shape of the piece. The present work highlights the difficulties we encountered and the solutions we identified, leading to an excellent matting system for the safe exhibition and preservation of the document.