Document Type


Peer Reviewed


Publication Date


Journal/Book/Conference Title

e-Preservation Science


Gelatin sizing was a key ingredient during the handpapermaking era. The gelatin concentration in historical papers has never been well documented, however, because measuring the gelatin content required destructive sampling. In this project we developed a non-destructive method using near infrared (NIR) spectroscopy. Gelatin concentrations of 40 historical papers from the 15th-18th centuries were determined from amino acid (AA) concentrations by using gas chromatography/mass spectroscopy. These values were combined with NIR spectra from the same papers to generate a model for predicting concentrations of unknowns. If a NIR measurement predicted a gelatin concentration in the range 0-6 percent then there is a 95% probability that the difference between the NIR model value and a destructive AA measurement would be between -1.6 and +1.3 percentage points. For 6-8 percent there is a 95% probability the difference would be between -2.0 and +1.5 percentage points, and for 8-12 percent the difference is between -3.0 and +2.0 percentage points. In a study of 159 specimens from books, loose leaves, and artworks printed from 1460-1791, the means for all papers were quite high in the 15th century and dropped an average of 20% every 50 years. Possible explanations for the decline are offered.


gelatin, sizing, paper, near infrared spectroscopy


Note: This MS has been accepted with minor revisions for publication in e-Preservation Science, the online conservation science journal. Those revisions are in place but have not yet been approved by the editors of the journal. We will provide a link to the final published version as soon as it is available.

Published Article/Book Citation

Forthcoming. The definitive version will be published in e-Preservation Science.


Author Posting © Morana RTD., 2011. This is the author's version of the work. It is posted here by permission of the publisher for personal use, not for redistribution.