Figure 4From: Winsor & Newton original handbooks: a surface-enhanced Raman scattering (SERS) and Raman spectral database of dyes from modern watercolor pigmentsSERS analysis of neutral tint. (a) SERS spectrum of reference alizarin compared to (b) that of Winsor & Newton neutral tint 20th century edition, and (c) SERS spectrum of reference carminic acid compared to (d) that of Winsor & Newton neutral tint 19th century edition (λexc = 488 nm). The most distinctive SERS peaks of alizarin (spectra a, b) and carminic acid (spectra c, d) are indicated in Figures 7 and 2, respectively.Back to article page