Fig. 4
Lac 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 text
