Part the fourth.
Chap. 89. How to paint in oil (I) on walls, pictures, iron, or whatever you please.
Before we proceed further, I will teach you to paint in oil, on walls, or on pictures (which is much practised by the Germans) (2), and also on iron or stone. But we will first speak of walls.
Chap. 90. How to begin painting in oil on walls.
Cover your wall with mortar, exactly as you would do when painting in fresco ; except that where you then covered but a small space at a time, you are now to spread it over your whole work. Make your design with charcoal, and fix it with ink, or verdaccio tempered. Then take a little glue much diluted — a whole egg, well beaten in a porringer, with the milky juice of the fig-tree, is still better: you must add to it a glassful of clean water. Then, either with a sponge or a pencil without a point, very soft, go once over the ground on which you are going to paint, and leave it to dry for one day at least (1).
Chap. 91. How to prepare good oil for tempering colours, and also for mordants, by boiling over the fire.
It will be very useful to you to know how to prepare this oil, either for mordants, or any other purpose ; therefore, take one, two, three, or four pounds (1) of linseed oil, and put it into a new pipkin ; if it be glazed, so much the better.
Procure a small furnace, and make a round hole, into which you are to put the pipkin, so that the flame may not reach it ; because if it were to take fire, you would run the risk of losing your oil and of burning the house. When you have made your furnace, put a moderate fire in it ; and the more slowly your oil boils, the better and more perfect will it be. Let it boil until it be reduced to half the quantity. But to prepare mordants, when it is reduced to half the quantity, add to each pound of oil one ounce of liquid varnish (pernice liquida), and let it be very fine and clear : and oil thus prepared is good for mordants.
Chap. 92. How to prepare good and perfect oil, by baking it in the sun.
When you have prepared this oil, which is done in another way (and is preferable for colours, but not for mordants), put some more linseed-oil in a basin of bronze or copper. And in August (quando è il sole leone) place it in the sun ; and if you keep it there until it be half wasted, it will be in a state for mixing with colours. And you must know, that at Florence this has been found the best mode of preparing it possible (1).
Chap. 93. How to grind colours in oil, and to use them on walls.
Let us return to grinding colours. You must grind them as you did when working in fresco, except that having then ground them with water, you must now grind them with oil. And when you have ground them, that is to say, all the colours (for every colour can be used in oil, except bianco sangiovanni), provide small vessels, into which put these colours, either of lead or of tin. And if yon can find none of either kind, get glazed vessels, and put the ground colours into them; shut them up in a box, and keep them clean. When you would paint a drapery with three gradations of colour, as I have previously taught you, divide, and let each colour be laid in its proper place with a pencil of minever, uniting one colour well with another, and making the colours very firm. Then rest for a day, and return again to your work, examine it, and repaint it where necessary. And in this way paint flesh (incarnazione), or any thing you please. Provide a vessel of tin or lead (somewhat like a lamp), about the height of your finger, half fill it with oil, and keep your pencils in it, that they may not dry (1).
Chap. 94. How to paint in oil on iron, on pictures, and on stone.
And in the same manner you may paint on iron, on stone, or on pictures, first passing some glue over them, and also on glass, or on any thing you please (1).
Chap. 95. How to adorn walls with gold and tin.
Having now taught you how to paint in fresco, in secco, and in oil, I will tell you how to embellish walls with gilded tin, white tin, and fine gold. And take especial notice, that you use as little silver as possible, because it becomes black on walls and on wood. Use instead of it beaten tin or tin plates (stagnuoli). Beware also of gold much alloyed (oro di metà), which quickly turns black.
Chap. 96. Shewing that you should use fine gold and good colours.
It is usual to adorn walls with gilded tin, because it is less expensive than gold. Nevertheless I give you this advice, that you endeavour always to use fine gold and good colours,
particularly in painting representations of our Lady. And if you say that a poor person cannot afford the expense, I answer, that if you work well (and give sufficient time to your works), and paint with good colours, you will acquire so much fame, that from a poor person you will become a rich one ; and your name will stand so high for using good colours, that if some masters receive a ducat for painting one figure, you will certainly be offered two, and your wishes will be fulfilled: according to the old proverb, Good work, good pay. And even should you not be well paid, God and our Lady will reward your soul and body for it (1).
Chap. 97. In what manner you should cut gilded tin, and ornament with it.
When you ornament any thing with tin, either white or gilded, and find it necessary to cut it with a knife, first procure a smooth plank of walnut, pear, or plum-tree, not too thin, cut in four like a real sheet of paper. Then take some liquid varnish, cover the board with it, and lay your piece of tin upon it, well spread and smooth. Then cut it with a knife very sharp at the point, and with a ruler cut
offa strip the width you intend to make your fringes (fregi), and finish them with black or other colours.
Chap. 98. How to make green tin for ornaments.
Sometimes, in order to embellish these fringes, you may grind verderame with linseed-oil, and spread it over a sheet of white tin, and it will be a beautiful green (1). Let it dry in the sun ; then fasten it upon a plank, with some varnish ; cut it then with a knife ; or if you would first stamp it with roses or other devices, spread liquid varnish upon the plank, and put your roses upon it ; then fix it to the wall. Again, if you would make stars of fine gold, or a glory round the head of saints, or ornaments with the knife, in the manner I have shewn you, you must first put fine gold upon gilded tin.
Chap. 99. How to gild tin, and how fine gold is laid on with gold size (doratura).
Gilded tin is prepared in this manner. Provide a smooth plank, three or four braccia long, grease it with fat, or with suet. Put some white tin on it ; then procure a liquor called gold size (doratura) ; put it upon the tin in three or four places, a very little in one place ; and with the palm of your hand spread the gold size over the tin equally, as much in one place as in another. Let it dry in the sun. When it is almost dry, but still a little sticky, prepare your fine gold, and cover the tin with it. Polish it with clean cotton ; stick the tin to the plank ; and when you would make use of it,
apply the liquid varnish, and make stars, or any ornaments you please, as I directed you to do with gilded tin.
Chap. 100. How to make and cut stars, and fix them on walls.
You must first cut out the stars with the assistance of a ruler ; and when you are going to use them, first put on the azure (where the stars appear) a lump of wax ; and work the stars in rays, as you have cut them out on the plank. And you must know that in this way there is much more labour, although you use less fine gold, than there is in gilding with mordants.
Chap. 101. In what manner this tin when gilded can be used for the glories of saints on walls.
If you would make the glories of saints without mordants, when you have coloured the figure in fresco, take a bodkin and scrape or mark out the glory above the contour of the head. Then, in secco, spread varnish upon the glory; put on it the gilded tin or fine gold ; then spread the varnish over it, strike it with Oe palm of your hand, and you will see all the marks made by the bodkin. With the point of a sharp knife gently cut away the loose gold, and remove it from the other part of your work (1).
Chap. 102. How to raise a glory in lime on walls.
You must know that if you please you may raise a glory with a trowel on the fresh mortar in this manner. When you have drawn the head of the figure, take the compasses and make the crown. Then take a little very rich lime, made into a paste, and spread over it, thickly in the further parts, but thinner near the head. Then take the compasses again, when you have smoothed the lime, and with the knife cut away the lime above the line of the compasses, and it will remain raised. Then have a strong stick of wood, and make the rays round the glory; and this is the way you are to make glories in relief on walls (1).
Chap. 103. How, after painting on walls, we proceed to paint pictures.
When you do not choose to adorn your figures with tin, you must use mordants, which may be applied on walls, on pictures, on glass, on iron, and on every thing: of these I shall hereafter treat in their order, and shall inform you what are strong, and capable of withstanding the air, the wind, and water; what require to be varnished, and what must not be varnished. But let us return to our colouring, and from walls proceed to pictures, which are the pleasantest and neatest part of our art (1). And remember, that he who learns to paint fiist on walls, and then on pictures, does not become so perfect a master of the art, as when he happens to learn to paint on pictures first, and then on walls.