A linear gradient elution method has been applied to the HPLC analysis of plant and scale insect red anthraquinonoid mordant dyes and molluscan blue and red-purple indigoid vat dyes. The method enables the use of the same elution program for the determination of different chemical classes of dyes. In addition, it significantly shortens the retention times of natural anthraquinonoid dyes over those previously published. For the first time a new dye, probably dibromoindirubin, has been detected in the Murex trunculus sea snail. The dye families investigated include the ones most often found on ancient textiles and shards from dyeing vessels in Israel and other regions.