§ XXIII. Thus, in the case of all sketches, etchings, unfinished engravings, &c., no one ever supposes them to be imitations. Black outlines on white paper cannot produce a deceptive resemblance of anything; and the mind, understanding at once that it is to depend on its own powers for great part of its pleasure, sets itself so actively to the task that it can completely enjoy the rudest outline in which meaning exists. Now, when it is once in this temper, the artist is infinitely to be blamed who insults it by putting anything into his work which is not suggestive: having summoned the imaginative power, he must turn it to account and keep it employed, or it will run against him in indignation. Whatever he does merely to realize and substantiate an idea is impertinent; he is like a dull story-teller, dwelling on points which the hearer anticipates or disregards. The imagination will say to him: "I knew all that before; I don't want to be told that. Go on; or be silent, and let me go on in my own way. I can tell the story better than you." Observe, then, whenever finish is given for the sake of realization, it is wrong; whenever it is given for the sake of adding ideas it is right. All true finish consists in the addition of ideas, that is to say, in giving the imagination more food; for once well awaked, it is ravenous for food: but the painter who finishes in order to substantiate takes the food out of its mouth, and it will turn and rend him. § XXIV. Let us go back, for instance, to our olive grove,--or, lest the reader should be tired of olives, let it be an oak copse,--and consider the difference between the substantiating and the imaginative methods of finish in such a subject. A few strokes of the pencil, or dashes of color, will be enough to enable the imagination to conceive a tree; and in those dashes of color Sir Joshua Reynolds would have rested, and would have suffered the imagination to paint what more it liked for itself, and grow oaks, or olives, or apples, out of the few dashes of color at its leisure. On the other hand, Hobbima, one of the worst of the realists, smites the imagination on the mouth, and bids it be silent, while he sets to work to paint his oak of the right green, and fill up its foliage laboriously with jagged touches, and furrow the bark all over its branches, so as, if possible, to deceive us into supposing that we are looking at a real oak; which, indeed, we had much better do at once, without giving any one the trouble to deceive us in the matter.