much ink that nothing short of a positively black background would
suffice to give a semblance of the delicate transparent effect of
the glass as a whole. The gray background would, therefore, be
lost, and if a really black object were also part of the picture
it could not be represented at all. Observe, in Fig. 27, how just
such a problem has been worked out by Mr. Harry Fenn.

It will be manifest that the student must learn to think of things
in their broad relation. To be specific,--in the example just
considered, in order to introduce a black object the scheme of
color would have needed broadening so that the gray background
could be given its proper value, thus demanding that the elaborate
values of the glass be ignored, and just enough suggested to give
the general effect. This reasoning would equally apply were the
light object, instead of a glass, something of intricate design,
presenting positive shadows. Just so much of such a design should
be rendered as not to darken the object below its proper relative
value as a whole. In this faculty of suggesting things without
literally rendering them consists the subtlety of pen drawing.

It may be said, therefore, that large light areas resulting from the
necessary elimination of values are characteristic of pen drawing.
The degree of such elimination depends, of course, upon the character
of the subject, this being entirely a matter of relation. The more
black there is in a drawing the greater the number of values that can
be represented. Generally speaking, three or four are all that can be
managed, and the beginner had better get along with three,--black,
half-tone, and white.

[Illustration: FIG. 28 REGINALD BIRCH]