Vibrational Spectroscopies and Chemometry for Nondestructive Identification and Differentiation of Painting Binders

Figure 6

PCA applied to combined FT-NIR and Raman first derivative spectra, taking into account all neat binding media: score plot of PC1-PC2 (a); loading plots of PC1 and PC2, highlighting in the different panels the bands associated with different materials: polysaccharides (a), lipids (b), and proteinaceous materials (c).

(a)

(b)

(c)