Since, then, in wood printing, you print from the surface left
solid; and, in metal printing, from the hollows cut into it, it follows
that if you put few touches on wood, you draw, as on a slate, with white
lines, leaving a quantity of black; but if you put few touches on metal,
you draw with black lines, leaving a quantity of white.

Now the eye is not in the least offended by quantity of white, but is,
or ought to be, greatly saddened and offended by quantity of black.
Hence it follows that you must never put little work on wood. You must
not sketch upon it. You may sketch on metal as much as you please.

78. "Paradox," you will say, as usual. "Are not all our journals,--and
the best of them, Punch, par excellence,--full of the most brilliantly
swift and slight sketches, engraved on wood; while line-engravings take
ten years to produce, and cost ten guineas each when they are done?"

Yes, that is so; but observe, in the first place, what appears to you a
sketch on wood is not so at all, but a most laborious and careful
imitation of a sketch on paper; whereas when you see what appears to be
a sketch on metal, it _is_ one. And in the second place, so far as the
popular fashion is contrary to this natural method,--so far as we do in
reality try to produce effects of sketching in wood, and of finish in
metal,--our work is wrong.

Those apparently careless and free sketches on the wood ought to have
been stern and deliberate; those exquisitely toned and finished
engravings on metal ought to have looked, instead, like free ink
sketches on white paper. That is the theorem which I propose to you for
consideration, and which, in the two branches of its assertion, I hope
to prove to you; the first part of it, (that wood-cutting should be
careful,) in this present lecture; the second, (that metal-cutting
should be, at least in a far greater degree than it is now, slight, and
free,) in the following one.

79. Next, observe the distinction in respect of _thickness_, no less
than number, of lines which may properly be used in the two methods.

In metal engraving, it is easier to lay a fine line than a thick one;
and however fine the line may be, it lasts;--but in wood engraving it
requires extreme precision and skill to leave a thin dark line, and when
left, it will be quickly beaten down by a careless printer. Therefore,
the virtue of wood engraving is to exhibit the qualities and power of
_thick_ lines; and of metal engravi