Fig. 4From: Microspectrofluorimetry and chemometrics for the identification of medieval lake pigmentsPrincipal component analysis scores, for normalized and filtered (by Haar transform and 1st derivative (2nd order)) excitation spectra for red lake pigments, illustrating the separation of the red lake pigments: kermes (light-blue), lac dye (dark-blue), cochineal (green) and brazilwood (red)Back to article page