Good question, Mike. I didn't know the answer for sure, but I was able to find some interesting info.
Alkanet is an ancient dye, with many names and many uses through history. There are dying recipes going back to Egyptian papyri. Here's a transcript of one:
"Grind some walnuts with some alkanet of good quality. This done, place them in some strong vinegar; grind again; add some pomegranate bark to this; lay aside three days; and after this, plunge the wool in it and it will be dyed cold. It is said that there is a certain acanthus which furnishes the purple color; moistened with some natron of Berenice in place of nuts, it produces the same effect.“
interesting side note: Another recipe calls for some drachma of urine, as a solvent I reckon
All that to say, it looks like the Egyptians ground it up before using it, so the idea of powderized alkanet is not new
