DOI Page / Citation link:
https://doi.org/10.11588/diglit.52444#0046
INTRODUCTION.
of a mordant or acid. Etching, therefore, involves the use of a fluid,
and hence is a wet process. Scratching with a point on the bare plate,
on the contrary, with sufficient force to produce a furrow does not in-
volve the use of a fluid. Hence it is a dry process, and as the instrument
used is a point, it is called “dry-pointing.” It is usually stated that the
point, in plowing through the plate, throws up a ridge of copper, which
it turns up alongside of the furrow, as the plowshare turns up the earth
while cutting the furrow in the ground. This is not, however, strictly
correct. In the first place, the dry-point cannot be compared to the
plowshare, as it is not pushed through the copper, but is held like a
pencil, and is drawn over the copper. The action of the plowshare is,
indeed, that of the graver, which is pushed, and throws the copper out
of the furrow produced. The point, however, does not remove the cop-
per, nor does it turn it up alongside of the furrow,— it merely raises it
over the furrow on one side of the point (see Fig. i), while on the other
side the pressure produces a very slight ridge. The metal projection
thus raised above the surface of the plate is called the bur. Generally
speaking, the edge of this bur is jagged, as shown in Fig. 2. It goes
without saying that the character of the bur depends on the angle
which the point forms with the surface of the plate. These statements
are the result of careful investigations made by the writer in preparation
for a course of lectures delivered before the Lowell Institute, at Boston,
some years ago. It is this projecting bur which catches the ink and
prevents the clean wiping of the plate, thus producing the rich velvety
effect so highly prized by the dry-pointer. By partly scraping the bur,
xxviii
of a mordant or acid. Etching, therefore, involves the use of a fluid,
and hence is a wet process. Scratching with a point on the bare plate,
on the contrary, with sufficient force to produce a furrow does not in-
volve the use of a fluid. Hence it is a dry process, and as the instrument
used is a point, it is called “dry-pointing.” It is usually stated that the
point, in plowing through the plate, throws up a ridge of copper, which
it turns up alongside of the furrow, as the plowshare turns up the earth
while cutting the furrow in the ground. This is not, however, strictly
correct. In the first place, the dry-point cannot be compared to the
plowshare, as it is not pushed through the copper, but is held like a
pencil, and is drawn over the copper. The action of the plowshare is,
indeed, that of the graver, which is pushed, and throws the copper out
of the furrow produced. The point, however, does not remove the cop-
per, nor does it turn it up alongside of the furrow,— it merely raises it
over the furrow on one side of the point (see Fig. i), while on the other
side the pressure produces a very slight ridge. The metal projection
thus raised above the surface of the plate is called the bur. Generally
speaking, the edge of this bur is jagged, as shown in Fig. 2. It goes
without saying that the character of the bur depends on the angle
which the point forms with the surface of the plate. These statements
are the result of careful investigations made by the writer in preparation
for a course of lectures delivered before the Lowell Institute, at Boston,
some years ago. It is this projecting bur which catches the ink and
prevents the clean wiping of the plate, thus producing the rich velvety
effect so highly prized by the dry-pointer. By partly scraping the bur,
xxviii