Figure 5
Raman analysis of neutral tint. (a) Raman spectrum of reference alizarin compared to (b) that of Winsor & Newton neutral tint 20th century edition, and (c) Raman spectrum of reference carmine naccarat compared to (d) that of Winsor & Newton neutral tint 19th century edition (λexc = 488 nm). (e) Raman spectrum of reference indigo compared to those of Winsor & Newton neutral tint (f) 20th century edition and (g) 19th century edition (λexc = 785 nm). The most distinctive Raman peaks of alizarin (spectra a, b) and carmine (spectra c, d) are indicated in Figures 8 and 3, respectively.