Researchers Find Clues in the Scent of Old Books

Posted on November 12, 2009

Researchers have found a fascinating new way to determine the degradation of old and rare books. The researchers got the idea to use smell to evaluate old books -- or other historical artifacts -- by watching rare book experts who often smell books as part of their examination. It turns out the the odor emitted by old books tells what kind of shape the book is in and whether it is in immediate need of restoration to keep it intact. The test developed by the researchers identifies the chemicals that the pages emit as they degrade over time.

The test does just that. It pinpoints ingredients contained within the blend of volatile compounds emanating from the paper. That mixture, the researchers say, "is dependent on the original composition of the... paper substrate, applied media, and binding". Their new method is called "material degradomics". The scientists are able to use it to find what chemicals books release, without damaging the paper. It involves an analytical technique called gas chromatography-mass spectrometry. This simply "sniffs" the paper and separates out the different compounds.

The researchers tested historical papers from the 19th and 20th centuries and found 15 compounds that were reliable markers of degradation. There are other compounds emitted, but these 15 reliably tell the researchers how far the book has degraded. Museums and libraries will eventually be able to use the test to reliably determine when an artifact needs to be restored. And it doesn't just work on books: other artifacts can be tested as well.