Fourth Section

How you Should Start for Working in Oil on a Wall
Chapter LXXXX
Plaster the wall the way you do for fresco; except that where you do the plastering little by little, here you are to plaster the whole job all at once. Then draw your scene with charcoal, and fix it either with ink or with tempered verdaccio. Then take a little well-diluted size. A still better tempera is the whole egg beaten up in a porringer with fig-tree latex; and pour a goblet of clear water over this egg. Then, either with a sponge or with the soft rather blunt brush, apply one coat of it all over the ground which you have to execute; and let it dry for at least one day.

How you are To Make Oil, Good for a Tempera, and Also for Mordants, by Boiling with fire.
Chapter LXXXXI
You ought to know how to make this oil, since it is one of the useful things which you need to understand; for it is used for mordants, and for many purposes. And therefore take one pound, or two, or three, or four, of linseed oil, and put it into a new casserole; and if it is a glazed one, so much the better. Make a little stove; and make a round opening so that this casserole will fit into it exactly, so that the flame cannot come up past it; because the flame would be glad to get to it, and you would jeopardize the oil, and also risk burning down the house. When you have made your stove, start up a moderate fire: for the more gently you make it boil, the better and more perfect it will be. And make it boil down to a half,[87] and it will do. But to make mordants, when it is reduced to a half,[88] put into it one ounce of liquid [p. 58] varnish which is bright and clear for each pound of oil; and this sort of oil is good for mordants.

How Good and Perfect Oil is Made by Cooking in the Sun.
Chapter LXXXXII
When you have made this oil, some may be cooked in another way besides; and it is more perfect for painting, but for mordants it has to be cooked with fire. Take your linseed oil, and during the summer put it into a bronze or copper pan, or a basin, and keep it in the sun when August comes. If you keep it there until it is reduced to a half,[89] this will be most perfect for painting. And know that I have found it in Florence as good and choice as it could be.

How you Should Work up the Colors with Oil, and Employ Them on the Wall.
Chapter LXXXXIII
Go back to working up or grinding, color by color, as you did for work in fresco; except that where you worked them up with water you now work them up with this oil. And when you have got them worked up, that is, some of every color, for all the colors will stand oil except lime white, get little lead or tin dishes into which to put these colors. And if you cannot find those, get glazed ones. And put in these ground-up colors; and put them into a little box to keep clean. Then when you wish to make a drapery in three values, as I have told you, mark them out and set them in their places with minever brushes, working one color well into another, keeping the colors quite stiff. Then wait a day or so, and go back, and see how they are covered, and lay them in again as necessary. And do the same for flesh-painting, and for doing any sort of work which you may care to carry out; and mountains, trees, and every other subject in the same way. Then have a plate of tin or lead which is one finger deep all around, like a lamp; and keep it half full of oil, and keep your brushes in it when idle, so that they will not dry up. [p. 59]

How You Should Work in Oil on Iron, On Panel, on Stone.
Chapter LXXXXIIII
And work on iron in the same way, and on stone; and on panel, always sizing first; and on glass likewise,[90] or wherever you wish to work.

The Way to Embellish with Gold or With Tin on a Wall
Chapter LXXXXV
Now, since I have taught you the method of working in secco, in fresco, and in oil, I wish to show you how you should embellish the wall with tin, golden and white,[91] and with fine gold. And know that above all you are to work with as little silver as you can, because it does not last; and it turns black, both on wall and on wood, but it fails sooner on a wall. Use beaten tin or tin foil instead of it henceforth. Also beware of alloyed gold, for it soon turns black.

How you should Always make a Practice of Working with Fine Gold and With Good Colors.
Chapter LXXXXVI
Most people make a practice of embellishing a wall with golden tin,[92] because it is less costly. But I give you this urgent advice, to make an effort always to embellish with fine gold, and with good colors, especially in the figure of Our Lady. And if you wish to reply that a poor person cannot make the outlay, I answer that if you do your work well, and spend time on your jobs, and good colors, you will get such a reputation that a wealthy person will come to compensate you for the poor one; and your standing will be so good for using good colors that if a master is getting one ducat for a figure, you will be offered two; and you will end by gaining your ambition. As the old saying goes, good work, good pay. And even if you were [p. 60] not adequately paid, God and Our Lady will reward you for it, body and soul.

How You Should Cut the Golden Tin, and Embellish.
Chapter LXXXXVII
When you are embellishing with tin, either white or golden,[93] so that you have to cut it with a penknife, first get a good, smooth board of nut or pear or plum wood, not too thin, the size of a royal folio in each dimension. Then get some liquid varnish; smear this board well; put our piece of tin on it, spreading it out and smoothing it down nicely. Then proceed to cut it with a penknife, well sharpened and . . .[94] at the point. And with a ruler cut the little strips of whatever width you wish to make the ornaments, whether just of tin, or wide enough for you to embellish them afterward with black or other colors.

How to Make Green Tin for Embellishing.
Chapter LXXXXVIII
Again, to embellish these ornaments, take some verdigris ground with linseed oil; and spread some all over a sheet of white tin, so that it will be a fine green. Let it dry well in the sun; then spread it out on the board with varnish. Then cut it with a penknife; or first make little rosettes, or any pretty trifles, with dies; and smear the board with liquid varnish, and set those rosettes out on it: then fasten them to the wall. Furthermore, if you wish to make stars with fine gold, or to apply the diadems of the saints, or to embellish with the knife as I have told you, you should first lay the fine gold on the golden tin.

How to Make the Golden Tin, and How to Lay Fine Gold with This Vermeil.[95]
Chapter LXXXXVIIII
Golden tin is made as follows. Set up a nice, smooth board, six [p. 61] or eight feet long; and have it smeared with fat or tallow. Some of this white tin is laid out on it; then a liquid known as vermeil is put on the tin, in three or four places, a little in each place; and you pat over this tin with the palm of your hand, so as to get this vermeil as even in one part as in another. Let it dry well in the sun. When it is almost dry, so that it is just a little bit tacky, take your fine gold, and systematically overlay and cover the tin with this fine gold. Then clean it up with some very clean cotton; separate the tin from the board. When you want to use it, work with liquid varnish; and make those stars with it, or any devices you wish, just as you do with the golden tin. [p. 62]

How to Fashion or Cut out the Stars, and Put Them on the Wall.
Chapter C
First you have to cut out all the stars with the ruler; and wherever you have to put them on, first put a little lump of wax on the blue, wherever the star comes; and shape the star on it, ray by ray, just as you cut it on the board. And know that much more work can be done with less fine gold than can be done by mordant gilding.

How You can make the Diadems of the Saints on the Wall with this Tin Gilded with Fine Gold.
Chapter CI
Likewise, if you want to make the diadems of the saints without mordants, after you have painted the figure in fresco, take a needle, and scratch around the outline of the head. Then after it is dry smear the diadem with varnish, put your tin on it, either golden or gilded with fine gold; put it over this varnish, pat it down well with the palm of your hand; and you will see the marks which you made with the needle. Take a well-sharpened knife point, and trim the gold up carefully; and put the surplus aside for your other jobs.

How You Should Model up a Diadem in Lime Mortar on a Wall.
Chapter CII
Know that the diadem wants to be modeled up with a small trowel on the fresh plaster, as follows. When you have drawn the head of the [p. 63] figure, take the compasses, and swing the halo. Then take a little very fat lime mortar, made into a sort of ointment or dough, and plaster this lime mortar rather thick around the outside of the circle, and thin in toward the head. Then when you have got the lime mortar quite smooth, take the compasses again, and with the penknife[96] cut away the mortar along the path of the compasses; and it will come out in relief. Then take a little slice[97] of strong wood, and indent the radiating beams of the diadem. And this wants to be the system for the wall.