When the art student sketches the masses of dark‐and‐light in pictures,
the “Spotting” as he calls it, he is studying Notan of two values, but in
an aimless way. He is hunting for some rule or secret scheme of
shading,—an “ornament,” “bird’s wing,” a “line;” vain search, for no two
works can have the same plan, each has its own individual line and tone.
On the other hand much can be learned by studying the masters’ plans of
composition,—not to imitate but to appreciate the harmony. One good way to
accomplish this is to sketch in the massing, in two values. Choose a
number of masterpieces, ancient and modern, and blot in the darks in broad
flat tones. This will reveal the general notan‐scheme of each picture (pp.
71, 72).