Fig. 5

Examples of chromatograms of the extracts of model papers and historical manuscripts. The arrow indicates the peak of alizarin. a and b: chromatograms recorded at 250 nm and 450 nm, respectively, of model paper dyed with madder without (blue) and with alum mordant (yellow); c and d: chromatograms recorded at 250 nm and 450 nm, respectively, of aged model paper dyed with madder without (blue) and with alum mordant (yellow); e and f: chromatograms recorded at 250 nm and 450 nm, respectively, of historical manuscript AP125-1; g and h: chromatograms recorded at 250 nm and 450 nm, respectively, of historical manuscript AS12