edges. A figure wholly dark, say in black drapery,
appearing against a light ground, might be supposed to be flat if no
cast shadow was seen; the same with the reverse--a light figure upon a
dark ground--except that in this latter case, unless the light was very
level and flat, a certain concentration of light upon the highest parts,
or indicating a modulation of shadow in interstices, might betray its
solidity (see p. 206[f111a]).

[Illustration (f111a): The Two Principles of Contrast in Black and
White.]

But if we place a figure so that the light falls from one side, we
perceive that it at once stands out in bold relief in broad planes of
light and shade, further emphasized by cast shadows (p. 207[f111b]).

[Illustration (f111b): Treatment of the Same Figure in Light and Shade.]

It would be possible to represent or to express a figure or object so
lighted by means of laying in the modulations and planes of shadow only,
or by means of adding the light only on a toned ground. In sketching in
black and white, it is a good plan to accustom oneself to complete as
one goes along, as far as may be, putting in outline and shadow
together; but this needs a power of direct drawing and a correctness of
eye only to be gained by continual practice. A slight preliminary basis
of light lines to indicate the position and proportions, and yet not
strong enough to need rubbing out, is also a good method for those who
do not feel certain enough for the absolutely direct method of drawing.

[Illustration (f112): Expression of Form by Light and Shade: (1) Light
and Shade Without Outline; (2) Light and Shade Enforced by Outline.]

Now in drawing, as I think I have pointed out before, no less than in
all art, there are two main governing principles of working which may be
distinguished.

I. The graphic aim.
II. The ornamental or decorative aim.

[The Graphic Aim]

The graphic aim--the endeavour to represent a form exactly as it
appears--a power always valuable to acquire whatever may be our ultimate
purpose, leaves the draughtsman great freedom in the choice and use
of line, or other means of obtaining relief, local tint, and tone.

In line-work the broad relief of the flat tones of shadow may be
expressed in lines approaching the straight, diagonally sloping from
right to left, or from left to right, as seems most natural to the
action of the hand.

The quali