Artistic Economy

This from M.F.K. Fisher's introduction to Map of Another Town:

Often in the sketch of a portrait, the invisible lines that bridge one stroke of the pencil or brush to another are what really make it live. This is probably true in a word picture too. The myriad undrawn unwritten lines are the ones that hold together what the painter and the writer have tried to set down, their own visions of a thing: a town, one town, this town.
Not everything can be told, nor need it be, just as the artist himself need not and indeed cannot reveal every outline of his vision.

I remember one of my favorite passages of one of the Ramona Quimby books described in great detail how Beatrice, Ramona's older sister, labored over a drawing of a fantasy dinosaur, determined not to over-do it. Often the true difficulty of art is not getting a point across. The difficulty is doing it without doing too much. It is probably one element of genius to give just enough and not over do it.