Non-Destructive near Infrared Spectroscopic Measurement of Antique Washi Calligraphic Scrolls

Degradation of antique washi paper was examined by non-destructive near infrared spectroscopy. Difference second derivative spectra of the modern minus antique samples were analysed for the absorption peaks due to the main chemical components of washi paper, i.e. cellulose and hemicellulose. The absorption peaks were decreased for amorphous and semi-crystalline regions of cellulose and for hemicellulose, showing the results consistent with conventional, destructive sugar analysis. It is concluded that near infrared spectroscopy is a useful technique for the non-destructive monitoring of the degradation of the chemical properties of washi paper.