Matija Strlič, Jana Kolar, Dirk Andreas Lichtblau
Degradation of paper-based collections is a consequence of a variety of factors, from endogenous (paper acidity, lignin content, etc.) to exogenous (pollutants, humidity, etc.). Environmental influences during long-term storage are undoubtedly important parameters. Studies have shown that increased humidity leads to higher rates of degradation of acidic paper, while the influence on mildly alkaline paper is less straightforward. The role of temperature is also crucial – it is possible to calculate how many times the lifetime of paper can be changed if the temperature of storage is increased or decreased by one degree Celsius. Volatile organic compounds (VOCs) are another subject which deserves attention, especially since they are both emitted and absorbed by paper. Studies have shown that such emissions can be substantial.
In any case, long term monitoring of large collections is needed to assess the influence of the storage environment and of the inherent material properties on the ageing behaviour of a collection. For such a task, a simple instrument is needed, which would allow us to survey a collection in a non-destructive, non-invasive and chemical-free manner. In the frame of the SurveNIR project, co-funded by the European Commission 6th Framework Programme, a consortium of research institutions and end-users set out to build a dedicated near infra red (NIR) spectroscopic instrument, which would enable the user to determine a variety of chemical and mechanical properties of paper, including naturally aged paper. The approach will be validated in several European collections in the British Library (London), Victoria and Albert Museum (London), National Archives (The Hague), National Archives (Stockholm), National Museum of Denmark (Copenhagen), National and University Library (Ljubljana), and State Archives of Dubrovnik.