CHARACTERIZATION OF HISTORIC PAPERS USING ATTENUATED TOTAL-REFLECTIONINFRARED-SPECTROSCOPY

Previous work has shown that there is a significant correlation betwee n the condition of several historic papers and their gelatin sizing co ntent as determined by wet chemical methods. We have investigated the use of attenuated total reflection infrared spectroscopy in conjunctio n with principal components regression (PCR) analysis as an improved m ethod to estimate gelatin concentrations as well as other properties o n historic papers. From a training set of 25 spectra obtained from han dmade papers dated from 1400 to 1800, the results from the PCR analysi s indicate that three factors correlate with gelatin concentration wit h a multiple correlation of 0.8057. Sulfur concentration and potassium concentration also correlate highly with the extracted factors with R values of 0.7937 and 0.8284, respectively. Other properties such as f luorescence, surface pH, date, L value, and iron concentration signif icantly correlate with one or more factors as well. The results sugges t that the method can facilitate further studies into the relationship between gelatin sizing and paper permanence as well as the relationsh ip between gelatin and other paper components.