Local Strenghtening of Mould-Damaged Manuscripts. A Case Study on Logbooks of Early French Expeditions in Louisiana (1684-1722)

The National Archives in Paris house the logbooks of early French expeditions in Louisiana, preserved in their original binding. They raise conservation issues specific to archival materials: iron gall inks are relatively well preserved but the paper is extremely weak on the edges, as a result of old water damages and micro-organisms growth. Using local consolidation techniques to strengthen the paper of these documents would prevent disbinding the manuscripts, hence allowing for minimal interference with the original binding structure. But these methods generate a substantial number of risks: formation of tide lines more likely to turn brown over time, local distortion of the paper, and iron gall ink migration. Often underestimated, the latter aspect should prevail in the decision-making process. Indeed, the formation of halos around and on the verso of the ink lines is often barely noticeable to the naked eye, but always comes with a migration of iron-ions, which is particularly detrimental to the manuscripts. We therefore sought the parameters of a local re-sizing technique that would limit, as much as possible, tide lines, distortions and ink migrations. After testing several methods, we opted for a 2 % Klucel G® in ethanol as adhesive and re-sizing agent. The solution was applied directly with a brush on damaged areas, in a local procedure combining re-sizing, lining with Berlin tissue, and infilling. This study provides an alternative to existing treatments that usually employ water-based adhesives. The result is a satisfactory local consolidation which preserves the original features of the ink, the paper, and the binding.