Restoration, book repairs and paper deacidification are the measures the Swiss National Library uses to preserve the original documents in its collections.
Paper made between 1840 and around 1990 contains acids that slowly break down its fibres. Roughly 80% of the documents held by the Swiss National Library are from this period and thus at risk of acid-related paper degradation. A chemical treatment is needed to neutralise the acids and stop the paper from deteriorating.
Restoration and book repairs
Our conservation guidelines state that we focus on preventive measures for entire collections rather than restoring individual documents. If necessary, original documents are restored or repaired with minimal intervention. The aim is always to ensure that the documents remain usable rather than to carry out a full restoration. Records are kept of all the work done. Partial restorations and simple repairs of damaged documents are performed in-house, whereas more complex restorations are handled externally.
Paper deacidification is performed as a batch process. Batches of up to 700 kg (approximately 2,000 documents) at a time enter the treatment chamber at a large-scale plant in Wimmis near Spiez, where the acid-containing paper is treated using the “papersave swiss” process. Books, boxes, folders and more are completely submerged in a special non-aqueous solution that reduces their acidity. Some 1.2 million documents weighing 483 tonnes, equivalent to 13.7 km of shelf space, were treated this way between 2000 and 2014, when mass deacidification was ended. The process is now used only for individual documents. “papersave swiss” extends a document’s lifespan by at least a factor of four, ensuring that it remains usable for generations to come.
Last modification 11.08.2022