If extensively used in an etching, the work
executed by the graver contrasts rather unpleasantly with the quality of
the etched work, as its lines are extremely clear cut. To get rid of
this inequality, it is sufficient to rebite the passages in question
very slightly, which gives to the burin-lines the appearance of etched
lines.

In short: use the graver with great circumspection, as its application
to works of the needle is a very delicate matter, and gives to an
etching a character different from that which we are striving for. It
seems to me that to employ it on a free etching, done on the spur of the
moment, would be like throwing a phrase from Bossuet into the midst of a
lively conversation.[17]

76. =Sandpaper.=--As regards other mechanical means, be distrustful of
tints obtained by rubbing the copper with sandpaper; these tints
generally show in the proof as muddy spots, and are wanting in
freshness. Avoid the process, because of its difficulty of application.
Only a very skilful engraver can put it to good uses.

77. =Sulphur Tints.=--I shall be less afraid to see you make use of
_flowers of sulphur_ for the purpose of harmonizing or increasing the
weight of a tint. The sulphur is mixed with oil, so as to form a
homogeneous paste thick enough to be laid on with a brush.

By the action of these two substances the polish on the plate is
destroyed, and the result in printing is a fresh and soft tint, which
blends agreeably with the work of the needle.

Differences in value are easily obtained by allowing the sulphur to
remain on the plate for a greater or less period of time. This species
of biting acts more readily in hot weather; a few minutes are sufficient
to produce a firm tint. In cold weather relatively more time is needed.
The corrosions produced in this way have quite a dark appearance on the
plate, but they produce much lighter tints in printing. If you are not
satisfied with the result obtained, you can rub it out with charcoal,
as the copper is corroded only quite superficially.

Owing to this extreme slightness of biting, the burnisher may also be
used to reduce any parts which are to stand out white.

This process, as you see, is very accommodating; but it is too much like
mezzotint or aquatint, and, furthermore, it can only be applied in flat
tints, without modelling. I have, nevertheless, explained it to you, so
that you may be able to use it, if you should have a notion to do so, as
a ma