PARTING,[194] THE OTHER FOR ENGRAVING & ETCHING.
First I will talk of that mixture with which you etch on copper
instead of cutting with the graver, this is an easy and a very
beautiful method. Aquafortis for etching is made thus: you take half
an ounce of sublimate,[195] one ounce of vitriol, half an ounce of
rock alum,[196] half an ounce of verdigris, and six lemons; and
after having care to pound the first mentioned substances well, you
boil them a little in the lemon juice, but not so as to let them
get too dry. The boiling should be done in a glazed pot, and if you
have no lemons you may take strong vinegar which will give a like
result. When you have well smoothed your copper plate you can take
any ordinary varnish,[197] such as is used for the lacquering of the
ornaments on daggers and other iron work, & heat it gently, putting a
little wax with it, this you do to prevent the varnish from cracking
when you draw upon it. It must not be too hot when you spread it on
your copper plate. When you have etched on your design make a ridge
of wax round the plate and pour on the parting water, letting it
stand not longer than half an hour. If then it be not bitten deep
enough, do it again. Then remove it and clean it well with a sponge.
You draw on the varnish with a stylus of well tempered steel, that
is an iron needle, which in the craft is termed a _stile_. You wash
the varnish off the plate with a sponge of warm oil, but very softly
so as not to destroy the intaglio. Then you use the plate & stamp
impressions on to card-board from it in just such a manner as plates
done with the graver. It is true that this sort of plate is produced
very easily, but then, you see, they don’t last near so long as
those done with the graver.
FOOTNOTES:
[194] _Acqua da partire is the acid into which you put alloys and
clippings, filings, etc., to separate gold from silver, or silver
from copper, or gold from gilt copper, in other words nitric acid_.
_Partitore is the man who exercises this trade_. _Hoepli’s Manual,
‘Oreficeria,’ published Milan, gives information about the modern way
of using acids for ‘separating or parting.’_
[195] _Solimato_: _can this be sublimed sal ammoniac?_
[196] _Allumi di rôcca._
[197] _Vernice ordinaria._