In order to make good foils for jewels it is essential to have steel
tools, and all of the best and of the most finished description.
Then, as you may suppose, for an undertaking of such importance you
need the greatest possible care and patience, together with the
greatest possible neatness. Long ago, when I was a lad of fifteen
and began to learn goldsmithery, I knew a master in the art whose
name was Salvestro del Lavacchio. This man only did stone-setting,
& specialised on the making of his own foils for all sorts of gems.
Though the foils from France and Venice and other places often showed
up more splendidly, experience proved that they were not as lasting
as Lavacchio’s, which were always thicker. For this reason the
setting of the gems upon them was often more difficult than on the
foreign foils, but so strong were they, and so telling to the gems,
that as soon as they became a bit known, he got orders from all over
the world and soon had no time for anything else but foil-making.
Indeed it requires all a man’s energies to do this, so I thought I
would give a few facts about it for the benefit of anyone anxious to
learn. The first foil is called the common foil, it is of a yellow
colour and is used for many jewels and transparent stones. But first
a word as to the weight of a carat, which is a weight of four grains.
The foils may be stated in weights thus:—
COMMON (YELLOW) FOIL.
9 carats of fine gold.
18 ” ” silver.
72 ” ” copper.
RED FOIL.
20 carats of fine gold.
16 ” ” silver.
18 ” ” copper.
BLUE FOIL.
16 carats of fine copper.
4 ” ” gold.
2 ” ” silver.
GREEN FOIL.
10 carats of fine copper.
6 ” ” silver.
1 ” ” gold.
Melt the copper well first and then put in the two other metals; when
they are well mixed cast them into a fairly long ingot mould, and
don’t make it too thick.[31] When it is cast let it cool, then file
it well, after which beat it very lightly and with the broad end of
a hammer, often heating it again as you go on, but not putting it
in water, nor cooling it with the bellows. And when you have beaten
it down to about the thickness of two knife backs; flatten it with
a strong rounded scraper, and pare off the edges quite smoothly
till no crack remain. Then, when you are spreading it out, see that
both it and your hammer be even, smooth, and burnished, and with
every possible care make it as thin as you can, as, according to
its nature, the metal will rend; the size of it should be about a
couple of fingers, or a little longer, and the square should be of
such dimensions as your metal will afford. Also mind that the size
is such as you propose to make when your work is completed. But as,
in beating, it will rend and crack, see that you watch this, and cut
it accordingly, and to the utmost thinness possible. And all these
pieces you must blanch, clean, and polish with tartar,[32] salt, and
water, which is the blanching liquor ordinarily used for silver. Then
wash in clear water, rub with a clean rag lightly, and then scrub it
on a big copper tube that must be very clean and shining.
See that you scrape it with the sharpest of all possible goldsmiths’
scrapers, and do this with the greatest care in order that you do
not mark it with notches. Then take it with a very clean and white
cloth, and have by you a graver that shall be well sharpened on an
oil stone, and clean off everything in the nature of grease or dirt.
It is needful, when burnishing it, to be in a room where there is
no dirt. Get a black hæmatite stone[33] such as the sword cutlers
use for burnishing gold. When you have polished it very well give
it its colour. This you do over a moderate and clean fire, keeping
your piece of foil near the said fire, and take care that of the two
sides, the unburnished one turns to the fire. Gradually you will see
the colour come according as it takes the heat. It is necessary to
vary the colour as need requires.
Pope Clement gave me the commission to make the button for his
cope.[34] This morse I made about the size of an ordinary plate; but
because of all its wealth of figure work I had better talk of that
later when I treat of embossing and the many difficulties of that
art. For the present I will consider only the jewels with which it
was enriched. In the middle of the morse I set a diamond the facets
of which were cut starwise to a point, for which Pope Julius II.
had given 36,000 ducats of the Camera. I set the stone quite free
(_à jour_) between four claws, in this manner did it seem to me to
make better. I had given this setting a good deal of thought, but
the stone was of such exceptional beauty that it caused me much less
trouble than costly stones of similar character are wont to do. True,
some jewellers were of a mind that it would be better to tint the
whole base of the stone and the back facets,[35] but with my good
results I got them to see that it was much better thus. Together with
the diamond, and around it, were two large ballas rubies and two big
sapphires, splendid stones, and four emeralds of a goodly size. To
all these stones did I apply those same careful methods of which I
have spoken above, thereby satisfying not only the Pope, but also
the practising artists. For, previously, at the beginning of the
work, and before I set to at the diamonds and the other stones—for
they were right difficult to handle—certain old fossils in the art
had, part in envy, part speaking true, sought to scare[36] me away
from the job. ‘Verily,’ said they, ‘we know you to be sure enough
in all that pertains to design & to the embossing of an excellent
piece of work, but when you set to the tinting and arranging of such
costly jewels, why, ’twill make the teeth chatter in your head with
fright.’ Now I’m not the sort of fellow who’s afeard of any mortal
thing, but I must say that this somewhat emphatic way of expressing
their astonishment made me pause a bit. But I minded me of those
gifts from God Himself, & which come to a man without any toil of his
own; comeliness for instance, or strength, or handiness, and to me
methought God had given surety of purpose. So much was this so, that
I could afford to turn laughing away from all their silly prattle.
The tale of Phœbus came to my mind, and how at the outset he had
sought to fright his son Phæton from wishing to guide the chariot of
the sun; but then, you see, when all was done, I was luckier than
Phæton, for I did not break my neck, but came out of it with much
honour and profit to myself.
FOOTNOTES:
[31] _Lo gitta in uno canale un poco largo, e non fare la verga molto
grosso._
[32] _Gomma._
[33] _Amatita nera._
[34] _This great piece, perhaps Cellini’s masterpiece, was melted
down in the present century._
[35] _Pàdiglione_: _or in English, pavilions_.
[36] _Spaventavano._