leenia, No I am not a Dyer, but I have studied Chemistry,and have a little knowledge of the Chemistry of dyeing. In my youth was conned into doing some experimental woad preparation and Body art hence the personal knowledge of the effects referred to above. The Woad used came from a museum specimen in the Pharmacy dept at a London University college, and was, therefore, the REAL thing!! The effects were as noted above, and as observed in the linked article, it had a powerful astringent effect the skin!! the Sunburn was very painful and the tanned/burned pattern took several months to completely disappear!!