An easy to use, non-destructive paper analysing technique is being used to identify the age and origin of old books and documents by researchers from Portugal.

Paper is one of the oldest and most common forms of carrying information. Vast knowledge about culture and the development of the human race is contained in paper documents. Analysis of these documents is important in discovering their origins, age and possible falsification. The elemental characterisation of paper can provide information about the age, origin and manufacturing technique used to produce a document, which is also useful in determining how best to protect and conserve valuable documents.

Using energy dispersive X-ray fluorescence (EDXRF), Luisa Carvalho and Marta Manso from the University of Lisbon analysed Rivista del Diritto Comerciale, an Italian book on law produced in 1941. Without any prior sample preparation, concentrations of several elements present in the paper from different sections of the book were determined directly. The results showed that the book was manufactured from three different kinds of paper.

This non-destructive method could be used to analyse older manuscripts. For example, unillustrated manuscripts from mediaeval times have been difficult to study, as traditional methods rely on analysis of pigments used in the artwork. Now, Carvalho's technique opens up the possibility of studying these just by analysing the paper.

Carvalho hopes that in the future, it might be possible to establish a database of the trace elements present in paper in order to identify it by means of key elements. 'There are specific elements or a combination of elements that are characteristic of a certain period or origin of paper,' explained Carvalho.

Another significant development would be to make a portable device to study precious documents that cannot be moved from museums. And some books, added Carvalho, can contain elements in the ink that are poisonous to humans. Elemental analysis of the pages will make it possible to discover such 'poisoning' books, said Carvalho.

Elinor Richards