Chapter XXX

. he describes the method of grinding gold for books. This is done by first filing the gold very finely and then gradually grinding it until it is an extremely fine powder. In the next chapter, which is entitled, “How Gold and Silver are Laid in Books,” the method of applying the gold is given. This is as follows: “Afterwards take pure minium and add to it a third part of cinnabar, grinding it upon a stone with water. Which being carefully ground, beat up the clear of the white of an egg, in summer with water, in winter without water, and when it is clear, put the minium into a horn and pour the clear upon it, and stir it a little with a piece of wood put into it, and with a pencil fill up all places with it upon which you wish to lay gold. Then place a little pot with glue over the fire, and when it is liquefied, pour it into the shell of gold and wash it with it. When you have poured which into another shell, in which the purifying is kept, again pour in warm glue, and, holding it in the palm of the left hand, stir it carefully with the pencil, and lay it on where you wish thick or thin, so, however, that there be little glue, because, should it exceed, it blackens the gold and does not receive a polish. But after it has dried, polish it with a tooth or bloodstone carefully filed and polished, upon a smooth and shining horn tablet. But should it happen, through negligence of the glue not being well cooked, that the gold pulverises in rubbing, or rises on account of too great thickness, have near some old clear of egg beat up without water, and directly with a pencil paint slightly and quickly with it over the gold; when it is dry, again rub it with the tooth or stone. Lay in this manner silver, brass, and copper in their place, and polish them.”

In this early period this form of gilding was certainly used a good deal, but soon after this the raised gilding, which was produced by laying the leaf on a raising made of gesso, was in general use. A number of different recipes have been found. Probably the most important, however, are those given by Cennino Cennini in the early part of the fifteenth century.