Fig. 4From: Organic colorants based on lac dye and brazilwood as markers for a chronology and geography of medieval scriptoria: a chemometrics approachLac dye paints, excitation and emission spectra from: 12th c.–13th c. Portuguese manuscripts that are represented as groups Lac 1 ( ), Lac 3 ( ), and Lac 4 ( ); sticklac (raw material, resin + chromophores); Al3+-laccaid acid A complex, applied on filter paper, pH = 3.5. For more details, please, see the textBack to article page