Fig. 4
From: Shine a light on papyrus: monitoring the aging process
Analysis of infrared spectra of aged papyri. a Detail of the infrared spectrum of light-aged samples, focusing on the area of the expected carbonyl and carboxyl bands. Background was subtracted and all spectra normalized to the highest peak of cellulose at 1030 cm−1; b Lateral order index vs. time for aged papyri with and without the influence of light, according to [33,34,35]