There is as much difference in the meaning of the words tone and tones as there is in the words nerve and nerves. - Arthur Hammond

The would-be picture-maker must learn to think pictorially; he must try to regard a picture as a pattern, as an arrangement of lines and shapes, making in themselves a pleasing and satisfying design, quite apart from the objects represented. The lines will form certain shapes, and the shapes will vary in tone; some may be light, some dark and some of intermediate shades of gray, which we call halftones.

...shading is of great importance, and good shadows can best be secured when the sun is low, and when one side of all objects is more strongly lighted than the other.

The emotions suggested by facts, not the facts themselves, are what concern the picture maker. This is where he is differentiated from those who seek to make only records and who are concerned only with facts.