As historical documents age they release a musty odour which is the result of chemical elements called volatile and semivolatile organic compounds (VOCs) from the paper seeping into the air. This smell can explain a lot about the condition of books as the composition of these VOC emissions changes significantly over time. The team, which included researchers from University College London, the Tate, the University of Ljubljana and Morana RTD in Slovenia, has developed a new method to identify the chemicals released by books as they decay. The technique, called material degradomics, links the book’s physical state to its VOC emissions pattern.
Researchers analysed 72 historical papers from the 19th and 20th centuries, including papers made with rosin (a pine tar resin), bleached pulp, groundweed, and rag fibre. They measured the VOCs from these papers and subsequently identified 15 compounds that appeared to show degradation.
It is hoped that such a chemical understanding of the state of degradation of historic documents will help museums and libraries to identify those most in need of preservation. Researchers also claim that the method could help to further develop preservation techniques and could be used on other historical artefacts.