Additional file 1 of The use of infrared spectroscopy and chemometrics to investigate deterioration in vegetable tanned leather: potential applications in heritage science

Additional file 1: Fig. S1. Boxplots showing range of intensity values obtained for peaks at (left) 2434 cm-1 and (right) 3222 cm-1, from all samples (regardless of pH). Fig. S2. PCA scores plots of analysis of FTIR data of leather, showing PC1 vs PC4. (Left) PCA of full spectrum, (Right) from PCA of 800-1800 cm-1. Later time points (14-28days) are clearly distinct from other time points in both analyses. Fig. S3. Clusters obtained from the k-means clustering of the time series trends for each peak in the FTIR spectrum region 800-1800 cm-1 of leather samples degraded at pH3 (black) and pH5 (red). Peaks following the same trends are clustered together, regardless of pH group.