A method for the non-destructive analysis of paper based on reflectance and viscosity

During research to assess the effectiveness of the mass deacidification treatment developed at the Universitat Politecnica de Catalunya (UPC-ETSIIT-Spain), the changes produced in several chemical and physical properties of papers dating from the 17(th), 18(th) and 19(th) centuries were compared, particularly the changes in viscosimetric degree of polymerization and colour parameters (lightness, chroma, and hue) caused by ageing and deacidification. A good statistical correlation between the colour differences of each sample versus a pure cellulose reference sample and the degree of polymerization for the same samples was observed. These findings will permit the use of the colorimetric method and the viscosimetric method for monitoring the conservation level of book and archival paper. It was also observed that E-. and DPv ranges under determined ageing conditions depend on the type of paper and its composition; so these properties could be used for the characterisation of papers by their age and manufacturing system.