Technique used in gilding, graffito allows to obtain small highlights or gilded decorations on colored backgrounds. These can be obtained by uniformly gilding the surface, spreading the color on it and then lightly scratching the color off according to the predetermined design.
How to represent a cloth of gold, or black or green, or of any color you please, on a ground of gold.
Before you begin to colour, I should like to show you how to make a cloth of gold. If you would have a mantle, or a woman’s petticoat, or a little cushion of cloth of gold, put on the gold-leaf with bole, and scratch (1) the folds of the drapery in the manner I have shown you formerly for putting on a background. Then, if you wish to make a red drapery, lay a flat tint of cinnabar upon the burnished gold. For darkening it, use lake ; for lightening it minium, all tempered with the yolk of an egg, not rubbing the surface too hard with your brush, nor touching it too many times. Let it dry, and go over it at least twice. In the same manner you may make green or black draperies, if you please. But if you would make a beautiful drapery of ultramarine blue, first lay a flat tint on the gold of biacca tempered with the yolk of an egg. When it is dry, temper your ultramarine with a little size, and a little yolk of egg, perhaps two drops. Pass it over the white two or three times, and let it dry. Then, according to the drapery you wish to paint, prepare your powders ; that is, you must draw the designs first on parchment and prick them in fine holes with a needle, holding a piece of cloth under the parchment, or, if you like, a board of lime-tree wood or alder wood; this is better than cloth. When the holes are pricked, take powder according to the colour of the drapery you have to transfer to. If it is white, dust with charcoal powder tied in a rag; if it is black, dust with biacca, also tied in a rag and sic de singulis. Make your transfer patterns match well at the edges.
1 “Grattare” here means to scrape lines and patterns through paint to the underlying gold easy with tempera paint a method frequently employed in ‘400 pictures ; it is more beautiful and brilliant than gilding with mordants.
How to draw, scratch, and grain a cloth of gold or silver.
Having transferred the design to the drapery by dusting powder (through the holes of the cartoon) take a stiletto (small style) of birch, or other hard wood, or of bone, pointed like a proper drawing style at one end, at the other blunt for engraving. And with the point of this style pick out the drawing of all the draperies, and with the other end scrape off the paint to the gold below, without rubbing off the gold, whatever you wish either in the background or the pattern work, and you can stamp patterns with the rosetta (2) on what you uncover. And if in certain small parts of the design you cannot use the rosetta, you must use an iron point like a drawing-style. And this is how you begin to learn to make gold draperies. If you would make silver draperies, you must proceed in exactly the same manner in putting on the silver as in putting on the gold. I advise you too, if you want to teach boys or children to put on gold, let them begin with silver, that they may get some practice, for it is cheaper.
2 No doubt the “rosetta” was a tool making a print of tiny indented clustered dots.