116 - [Prepared Wool Shearings to Make a] Lake of Kermes for Painters
Take 1 lb of white woolen cloth shearings, which are of a fine wool, hold these shearings in fresh water for a day, then wring them out well, and this takes away the unctuosity that [the wool] has when it is sheared, which comes out of the hide. Now mordant them in the following way.
That is to say, take 4 oz of roche alum, and 2 oz of pulverized raw tartar. Put them in a small kettle with approximately 3 flasks of water. As soon as it begins to boil, put in the shearings and Iet them boil for ½ hour on a slow fire.
Then remove them from the fire, and leave them to cool for 6 hours. Now gather the shearings, wash them with clear water, and Iet them sit for 2 hours, then thoroughly wring the water out of the shearings and leave them to dry [in preparation for chapter 117].