"The alchemical texts written in Egypt in the third century AD, in particular, Papyri Leidensis (Berthelot 1887) and Graecus Holmiensis, (Lagercrantz 1913), with probable roots in much earlier traditions (Reinking 1925), also mention specific materials and procedures..."
Interesting find, thanks. They forgot to mention in the abstract that extracting the dye was a very smelly business apparently, because you had to ferment it in the open air to get it in the right state, IIRC.
