How colours are to be prepared: beginning with azure.
If you wish to make the finest azure, take a new pot-one that has never been in use-and put in it as many leaves of very pure silver as you wish; and put the pot into the marc, which has been thrown out of the wine-press, and cover it up well with the marc and keep it carefully for fifteen days. Then open the pot, and scrape out into a very clean dish the colour which surrounds the leaves of silver. And if you want more of it, replace the leaves as often as you like.