Historical Painting Techniques, Materials, and Studio Practice

[37] To make crude verzino for writing and miniature painting. Take the brazilwood
and finely scrape of the quantity you think you need, with a piece of glass.
Put these scrapings in a new glass. Add so much vinegar to it, that it covers
the brazilwood half a fmger's width, and not more. The vinegar must be
strong and clear. Add to the substance in this glass the quantity of about a
bean of gum Arabic and the same amount of well-pulverized roche alum.
Place it in the sun and make sure that the glass is well covered. Keep it this
way for three or four days. If there is no sun, then keep it for four days so
close to the fire that it gets lukewarm. When it is warmed this way, put it in
shells as shown here, and let it stand in these shells, until it seems done to
you. Know that the longer it remains, the better it is. Next put it in a bottle.
{17v} Write with this on your work. If you want to make red clothlet colors
of it, dip in to soak the pieces of cloth and let them dry in the previously
described way, except that in the making of the clothIets [neither] the alum
nor the gum Arabic should be used.
[38] To make a purple clothlet for writing and miniature painting. Take the petals
of the "papatello," which is a sort of wild poppy. Crush them and take out
the juice. To one glass of juice it needs to have about the size of a bean of
well-pulverized roche alum. Then dip in the piece of cloth, once or twice,
until you think that it has taken enough of the color.
[39] To make a beautiful blue at little cost. Take quicklime and green and ground
verdigris and sal armoniac, as much of one as of the other. Grind these all
together with urine and you will see a beautiful blue. Temper it with the
previously described glair, when you want to work with it (31).
[40] To make invisible letters, which you cannot see unless near the fire. Take sal
armoniac, the amount of it is about the size of a chestnut to half a glass of
water. Write with this water when it is dissolved, and if you want to read it
you heat the parchment near the fire and the letters will appear as if they
were written in ink.
[41] To make black letters with every water you write. Take galls and vitriol, as
much of one as of the other. Grind it and sieve it and put it on the parchment
like a varnish coating. Next write on this with any water you want and while
you are writing the letters will appear black.
[42] To erase letters from goatskin parchment without a scraping iron. Take the juice
of a lemon or of a strong orange and immerse {18r} a sponge in it. Rub
with this sponge on the letters and they will be taken off as if they never had
been written.
[43] To make a ground fo r gold. Take slaked gypsum, as much as you need, and
Armenian bole about one third of the gypsum, and of aloe one third of the
bole. Then grind everything together very fine with water on the porphyry
stone. Let it dry on the porphyry stone and then grind it again very fine.
Add a little bit of candy sugar and when it is ground enough, gather it in a
glazed horn and temper it with equal quantities of the aforesaid glair and
water of animal glue, that is hide glue. Make this gold ground so liquid that
it flows from the pen and write whatever you want. And if it appears not to
have enough volume, write over it a second time, like before. Scrape it carefully
with a scraping iron when it is dry, so that the letter will be plane and
smooth. When you want to lay the gold, huff on the letter and immediately
lay the leaf of gold or silver. Press on it with the calf's tooth. Then clean it
with some cotton wool so that what sticks out from the letter will be wiped
off. If you want to make a head of a frame with this gold ground with the
brush like described, paint it over the first application and then scrape it and
lay the gold.
[44] To make French glue for many purposes. Take animal glue, i.e. bone glue,
and put it to soak in so much water that it covers the glue. Put it to soak in
the evening and put it on the fire in the morning. When you soak it, it does
not matter {18v} if there is not enough water to cover it completely, because
Wallert 43