CHAPTER XVI

THE GILDING METHODS OF THE MIDDLE AGES

The most casual observer cannot fail to notice the gilding that is such a prominent feature of the MSS. of the mediæval period. Brightly burnished gold, which appears as if it had been laid and burnished quite recently, although centuries have passed since the work was completed, cannot fail to impress and arouse one’s curiosity as to the gilding methods employed when this work was produced.

Some of the old MSS. that treat of painting and the preparation of colours give also some information concerning the various methods of gilding, and our knowledge of these methods is chiefly derived from these MSS.

Dr. A. P. Laurie has made careful examination of the different forms of gilding employed in illuminated MSS., and in his book, “Pigments and Mediums of the Old Masters” says that gold was used in three distinct forms: as gold-leaf laid on the surface, and in the form of gold paint, prepared by grinding leaf-gold to powder; the other method seems to have been a paint made of rounded granules of gold. He suggests that this gold was probably obtained from river washings, and that the only preparation has been to sift out the finer grains. He says, further, that when it is examined under the microscope this form of gold paint is easily distinguished from that prepared from leaf-gold, which presents the appearance of little particles of gold with sharp corners and edges, while this shows rounded granules.

The art of gold-beating is of very great antiquity. Pliny, in his “Natural History,” states that one ounce of gold was made into 750 leaves, each leaf being four fingers square. This is about three times as thick as the ordinary gold-leaf of the present day. It is very difficult to form any idea as to when and where it originated. Some think that it arose amongst Oriental peoples. It certainly has been practised amongst these since quite remote periods. Some of the coffins of the Egyptian mummies have gilding on them evidently done with gold-leaf in a similar way to modern methods. Some of the books of gold-leaf used by the ancient Egyptians are in existence to-day, there being one at the Louvre in Paris.

Pliny says, “Gold-leaf is laid over marble, etc., with white of egg, on wood with glue properly composed; they call it leucophoron.” In another place he states that leucophoron is composed of sinopia (a red earth colour), light sil (yellow ochre), and melinum (a white earth). Evidently this was mixed with size to form a ground upon which to lay the leaf.

The Lucca MS., of the eighth century, gives instructions how to prepare gold for writing by reducing the metal to a fine powder to form a gold paint.

The following recipe is from the “Mappæ Clavicula,” a MS. of the twelfth century: “If you wish to write in gold, take powder of gold and moisten it with size, made from the very same parchment on which you have to write; and with the gold and size near to the fire; and, when the writing shall be dry, burnish with a very smooth stone, or with the tooth of a wild boar. Item, if then you wish to make a robe or a picture, you may apply gold to the parchment, as I have above directed, and shade with ink or with indigo, and heighten with orpiment.”

Parchment size is prepared by boiling parchment or vellum cuttings with just enough water to cover them for about two hours. The size is then poured off and sets in a firm jelly when quite cold. When required for use a small portion is placed in a jar, which is put into a basin of hot water, the size then quickly becoming liquid.

In the writings of Theophilus, of about the same period, he gives a good deal of information concerning the mediæval methods of gilding. In Chapter XXIV. he gives directions for hammering out gold-leaf. The next chapter, which is quoted, explains how the leaf is laid on. “In laying on gold, take the clear part of the white of egg, which is beat up without water, and then with a pencil paint lightly over the place in which the gold is to be placed, and, the handle of the same pencil being wetted in your mouth, touch one corner of the cut leaf, and so elevating it, lay it on with the greatest quickness, and spread it even with a brush. And at that moment you must beware of a current of air and refrain from breathing, because if you blow you lose the leaf and with difficulty recover it. When this is laid on and dried, superpose another upon it, if you wish, in the same manner, and a third likewise, if it is necessary, that you may be able to polish it more brightly with a tooth or a stone.”

Evidently this was the general method of gilding, for he states that the leaf can be laid in the same manner on a wall or ceiling.

In 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. Chapter CLVII. is entitled, “How You Must do Miniature-Painting and Put Gold on Parchment.” It is quoted in full. “First, if you would paint miniatures you must draw with a leaden style figures, foliage, letters, or whatever you please, on parchment, that is to say in books; then with a pen you must make the delicate permanent outline of what you have designed. Then you must have a paint that is a sort of gesso, called asiso, and it is made in this manner; namely, a little gesso sottile and a little biacca, never more of this than equals a third part of the gesso; then take a little candy, less than the biacca; grind these ingredients very finely with clear water, collect them together, and let them dry without sun. When you wish to use some to put on gold, cut off a piece as large as you have need of, and temper it with the white of an egg, well beaten, as I have taught you. Temper this mixture with it; let it dry; then take your gold, and either breathing on it or not, as you please, you can put it on; and the gold being laid on, take the tooth or burnishing-stone and burnish it, but hold under the parchment a firm tablet of good wood, very smooth. And you must know that you may write letters with a pen and this asiso, or lay a ground of it, or whatever you please--it is most excellent. But before you lay the gold on it, see whether it is needful to scrape or level it with the point of a knife, or clean it in any way, for your brush sometimes puts more on in one place than in another. Always beware of this.”

The next chapter is also quoted, as it gives another method of laying gold on parchment. “If you would like another kind of asiso--but this is not so good, but may be used for putting on gold grounds, though not to write with--take gesso sottile, and a third part biacca, a fourth part Armenian bole, with a little sugar; grind all these very finely with the white of an egg; lay on the ground in the usual manner, and let it dry; then with the point of a knife scrape and clean the gesso. Put the previously mentioned tablet under the parchment, or a very flat stone, and burnish it; and should it by chance not burnish well when you put on the gold, wet the gesso with clean water with a small minever brush, and when it is dry burnish it.”

Gesso sottile was plaster of Paris that had been thoroughly slaked by long soaking in water so that it had lost all its setting properties. As mentioned in a previous chapter, biacca was white lead. The white of egg is prepared by beating it thoroughly to a thick froth and letting it stand one night to clear itself. Armenian bole is a red earth colour which seems to have been used a great deal to give colour to the ground for gilding. In some of the MSS. where the gold has been slightly rubbed off, the red colour of the raising preparation plainly indicates that is one of the ingredients used.

In Chapter CLX. instructions are given on “How to Grind Gold and Silver, and How to Temper Them to Make Foliage and Embellishments.” Evidently in this case the gold was prepared by grinding the leaf-gold--not, as was the case in the earlier descriptions, by first filing the metal and gradually reducing it to a fine powder.

The powder gold was, however, generally used only for painting in fine gold lines and heightening miniatures, although in the latter part of the fifteenth century matt gold grounds were often used as borders round miniatures, etc.

The raised gilding was, however, used more often, and the various recipes given in the different MSS. are generally very similar to those given by Cennino. Sometimes chalk or pipe-clay is used instead of gesso, and occasionally parchment size or fish-glue is recommended as a medium for mixing it with.

Endeavouring to work from these recipes is no easy matter, and the student is not advised to waste too much time in experimenting in this direction. Although there is a certain amount of fascination in trying the various preparations and methods, there is so much that is important that should claim the attention of the student that it is hardly profitable for him to spend a lot of time trying to work from these old formulas when it might be better employed.

One cannot help being interested, however, in these old recipes and directions for applying gold to vellum.