First you must consider whether the figures have the relief required
by their situation and the light which illuminates them; for the
shadows should not be the same at the extreme ends of the
composition as in the middle, because it is one thing when figures
are surrounded by shadows and another when they have shadows only on
one side. Those which are in the middle of the picture are
surrounded by shadows, because they are shaded by the figures which
stand between them and the light. And those are lighted on one side
only which stand between the principal group and the light, because
where they do not look towards the light they face the group and the
darkness of the group is thrown on them: and where they do not face
the group they face the brilliant light and it is their own darkness
shadowing them, which appears there.
In the second place observe the distribution or arrangement of
figures, and whether they are distributed appropriately to the
circumstances of the story. Thirdly, whether the figures are
actively intent on their particular business.
555.