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should be fresh and clear and of little color. Know that the quality of the
right gum can be recognized in that it is difficult to break. The gum that
comes in small grains is much better. The good quality Roman vitriol can
be recognized by its blue color and [its texture], in that it is hard and grainy,
like coarse salt. It is sufficiently good when the rain water or river water is
soft, but better is that which comes from the fo untain. Good galls are rec
ognized by their being small and wrinkled, and hard inside (8).
[6] To make a good yellow. Take an egg and take out the white of it and put
it in a glazed pot. Put in as much saffron as seems right to you. Take a wooden
mixer and beat it so much that the egg white breaks and becomes nicely
yellow. Then take a fine clothlet and sieve [the glair mixture] through it in a
glazed dish and leave it {12r} in the sun to dry. Then take it out, keep it dry,
and when you want to work with it, grind it with a little bit of water and a
fe w drops of glair (9).
[7] To make a fine lac. Take a man's urine, as much as you need, put it in a
bowl and let it stand fo r eight days. Then put it in a pot and let it boil so
long that there is no fo am anymore. Then percolate it through strong ashes,
so that the liquid that comes through is like a lye. When you have sieved it;
take coarse gum lac and crush it until gets the appearance of bread crumbs,
put it in a new pot, and put in the said ... (10).
[8] To make indigo. Take flower of woad and flour of grain. Make a dough
of it with urine and with vinegar. Make a cake of it and dry it in the sun.
And if it is too light, take more flower of woad and mix it again until it takes
on the color you want (11).[9] How to make vermilion. Take one part of mercury and one of white sulf ur,
as much of one as of the other. Put it in a glass bottle, thoroughly clad with
clay. Put it on a moderate fire and cover the mouth of the bottle with a tile.
Close it when you see yellow smoke coming out of the bottle, until you see
the red and almost vermilion-colored smoke. Then take it from the fire and
the vermilion will be ready (12).[10] To make burnished gold lines. Take slaked gypsum, ground with glair and
a bit of honey, and some earwax subtly ground together with a little bit of
bone glue. Let it dry when you have applied it. Then huff on it, lay on the
gold, and polish it (13).
[11] A way to test whether the ultramarine blue is good. Take an iron knife and
hold it in the fire. Then take a little bit of the blue and put it on this
knife, and if it is good {12v} it will become more beautiful and of a tender
color. If it is not good, it will become black like ink (14).[12] To make blue. Take a glass pot and put in it fr esh sulfur and mercury,
thoroughly mixed. And take two parts of sulfur to three parts of mercury.
Clad the pot with white potters clay and make sure that this is thoroughly
mixed with horse dung. Put this to heat well on the fire, until the smoke
comes out of it. Then take it off the fire and it will be a perfect blue (15).[13] To make a blue water. Take from the elder tree the berries with the
kernels, at the time when they are in the stage between green and ripe. Cook
them in a kettle and when they are boiled enough, take a cloth and squeeze
the juice that comes out of them in a glass or glazed pot. Then temper it
with urine and use it as a painter's color. When it is dry you can lightly paint
with the juice oflilies with a brush on it, and it will be a blue color. Similarly,
you can dye cloths with it or paper to write on with letters in gold.
[14] How to make red lead. Heat litharge together with rasped lead in the fire.
This makes the red lead.[15] How to make the dark "verzino." If you wish to make the dark verzino,
take about a "quarto" of rasped brazilwood. Put it in a beaker. Take white of
egg, thoroughly beaten fine with a sponge and put it fo r eight days in a bottle
with some realgar. Mix it together after those days. Then sieve this verzinoHistorical Painting Techniques, Materials, and Studio Practice