Oldal 42 [42]
OCR
20 LIGHT AND WATER should great accuracy be required; though, as water is hardly ever quite still, reflexions are seldom distinct enough to need very exact drawing. But whatever the object reflected, whether building, rock or tree, it is important to bear in mind that the image of any point lies exactly beneath that point, and must therefore be drawn vertically below it. A slight neglect of this precaution may destroy the whole force or charm of a sketch. It sometimes happens, however, that the reflexion of a sloping tree-stem appears to be shifted a little to one side, for the base of the stem, though itself in full view, cannot be seen by reflexion, its image being hidden by the image of the bank, and the first appearance of the stem in the water is therefore to one side of the base. If the water is a little rippled, so that the image is drawn out and blurred, the deception may be increased. And when the ripples are running both in the object and the image, such as E, will converge to the other vanishing point VP. Draw a vertical line through VP’. Then whatever pitch we choose for the roof of the house, the edges F, G, of the near side must vanish to an accidental vanishing point in this line above VP’, say AVP’. The roof of the small building has the same pitch, and therefore F, G, I and K are all representations of parallel lines and must all meet at the point AVP’. And it may easily be shown (assuming the farther and nearer slopes of the roof to be of the same pitch) that the edges H, L, of the farther side will vanish to a corresponding point, av/’, as far below VP, as AVF ts above tt. Now, in the image, the nearer edges f, g, ? and & of the gables are parallel to the farther edges H, L in the object, and also 4, / in the image are parallel to F, G, I and K in the object. Therefore the lines 7, g, z, & will vanish also in av, and 4, 7 in AVP’.
