If it is a street, and if you wish to express its perspective, and the bit of blue sky beyond, with a burst of sunlight illumining the corner, the figures crowded against the light, forming a mass in themselves, and it interests you at a glance, sit down and study it long enough to find out what feature of the landscape impressed you at first sight. If, as you look, the first impression becomes weakened, perhaps it is because the immediate foreground, which at the first glance was clear, is now dotted with passers-by, thus obscuring your point of interest, or a cloud has passed over the sky, lowering the whole tone, or the group of figures across the light has dispersed, exposing the ugly right-angled triangle of the flat wall and street level instead of the same lines being broken picturesquely with the black dots of heads of the crowd itself. In a moment it is no longer a composition of the same power that struck you at first. Perhaps while you sit and wait the scene again changes, and something infinitely more interesting, or the reverse, is evolved from the perspective before you. And so it goes on, until this constantly changing kaleidoscope repeats itself in its first aspect, until you have fairly grasped its meaning and analyzed its component parts. Or until either the effect that first delighted you, or the subsequent effect that charmed you still more, becomes a fixed fact in your mind. That, then, is the picture that you want to paint and that you are to paint exactly as you saw it. And if you can reproduce it exactly as you did see it, ten chances to one it will impress your fellow men. The trouble is that when you sit down to paint it you are so often lost in its detail that you forget its salient features, and by the time you have finished and blocked up the immediate foreground with figures that did not exist when you were first thrilled by its beauty, you have either painted its least interesting aspect, or you have filled that street so full of lies of your own that the policeman on the beat could not recognize it.
Of course, while all nature is interesting, there are parts of nature more interesting than other parts, and since the skill of man is inadequate to produce its more humble effects, if I may so express it, the painter should be on the lookout for her dramatic air, in order that when she is reproduced she may add that touch to her many qualities, thus meeting the painter half-way. Even in the perspective of a street, nature, in profound consideration of the devotee under his umbrella, often gives him a deeper touch—one wall perhaps in sudden brilliant light, while the vista of the street is in gloom made by a passing cloud, she constantly calling out to the painter as he works: "Watch me now and take me at my best."
Or change this picture for an instant and note, if you please, the flight of cloud shadows over a mountain slope or the whirl of a wind flurry across a still lake. There are moments in all phenomena like these where a great man rising to the occasion can catch them exactly, as did Rousseau in the golden glow of the fading light through the forest, or Corot in the crisp light of the morning, or Daubigny in the low twilight across the sunken marshes where one can almost hear the frogs croak.
Selection, then, preceded by the deepest and closest thought as to whether the subject is worth painting at all, becomes necessary, the student giving himself plenty of time to study it in all its phases; time enough to "walk around it," reviewing it at different angles; noting the hour at which it is at its best and happiest, seizing upon its most telling presentment—and all this before he begins even mentally to compose its salient features on the square of his canvas. You can turn, if you choose, your camera skyward and focus the top of a steeple and only that. It is true, but it is uninteresting, or rather unintelligible, until you focus also the church door, and the gathering groups, and the overgrown pathway that winds through the quiet graveyard. So a picture can be true and yet very much like a slip cut from a newspaper. For some men cut thus into nature, haphazard, without care or thought, and produce perhaps a square containing an advertisement of a patent churn, a railroad timetable, and a fragment of an essay on art. Cut carefully and with selection, and you may get a poem which will soothe you like a melody.
As to the value of the laws which govern the perfect composition, it is unquestionably true that a correct knowledge of these laws makes or unmakes the picture and establishes or ruins the rank of the painter. No matter how careful the drawing, how interesting the subject, how true the mass, how subtle the gradations of light and shade, how perfect the expression of the figures, or how transparent the atmosphere of a landscape, a want of this knowledge will defeat the result. On the other hand, a good composition—one that "carries," as the term is—one that can be seen across the room, if properly composed will instantly excite your interest, even if upon near inspection you are shocked by its crudities and faults. "I don't know what it is," says a painter, "but it's good all the same."
After your selection has been made, the next thing is to search for its centre of interest. When this is found it is equally important to weigh carefully the quality of this centre of interest in order to determine whether, as has been said, the subject is worth painting at all. My own rule is to spend half the time I am devoting to my sketch in carefully weighing the subject in its every detail and expression.
Many men, I am aware, have endeavored to prove that there are eight or ten different forms of composition. My own experience and investigation are, of course, limited, but so far I have only been able to discover one, namely, the larger mass and the smaller mass: the larger mass dominating the centre of interest, which catches your eye instantly at first sight of a picture, and the smaller or less interesting object which next attracts your eye, and so relieves the vision and spares you the monotony of looking at a single object long and steadily, thus fatiguing the eye and dissipating the interest.