Note T — Chapter XVIII
Edwin C. Middleton translation
For etching extremely delicate transfers a decoction of Aleppo gall with gum is to be recommended. 15 gr. of crushed nut galls are boiled for one hour in half a kilo of water and strained through a cloth. To etch the transfer add a few drops of this solution to a solution of gum of a syrupy consistency; spread over the stone with a soft sponge, and allow to dry.