Fig. 9

Raman spectra of pigments identified in the tube colours. The spectra depicted are a chrome yellow in “Chromium yellow light”, b Prussian blue and organic dyes in “Green lake light”, c hematite in “Red oxide” from Averhoff, and d alizarin in “Red oxide” from Pacht. The spectra were assigned by comparison of the spectra to those in the literature [8, 9]. The peaks in b arising from the organic dyes has not been assigned