More on the same subject. Take brazil, freshly tempered with very carefuily prepared white of egg. Lay it upon the parchment of calf or other skin, wherever you wish to put the gold. Apply the gold at once, and scarcely touching it, press it down with the cotton, and leave it for half a day to dry. Then take a dog's tooth, and begin to burnish, rather gently at first, so as not to spoil it ail; and then so strongly that your forehead becomes moist with perspiration.
When you lay gold on parchment made of ram-skin, add a little of the gum of the cinus tree. For that gum, otherwise gum arabic, is wonderful for working upon any sort of parchment. And either kind of gum may be prepared as follows: take the gum, and bind it up in a very clean cloth, and put it in a glass vessel, under water, for a whole day and night. Or if you wish to make haste, rub it up in water with your finger. So draw whatever you wish with the quill upon the parchment, and lay the gold on it, as has been described. But observe that you will do well to work in a damp place, especially in warm weather, which often injures burnished gold and colors.
Nevertheless, colors call for harsh, dry weather.