13. Effect is to be produced best, by strong contrasts of light and shade both in earth and sky; but the student's taste must determine where these shall fall, and though the contrasts should be strong, yet gradation, in both, must be observed.
14. A predominancy of shade has the best effect; and light, though it should not be scattered, must not be drawn, as it were, into one focus.
15. The light, in a picture, is best disposed when the fore-ground is in shadow, and it falls in the middle; but this rule is subject to many variations. Light should rarely be spread on the distance.[5]
16. It is useful to know, that the shadows of morning are darker than those of evening; also, that when objects are in shadow, their light (as it is then a reflected light,) falls on the opposite side to that on which it would come if they were enlightened.
17. The harmony of the whole should be studied; if the piece strikes you as defective in this respect, place it at evening in some situation where it will not be reached by a strong light, when the misplaced lights and shadows will strike you more forcibly than in the glare of day.
18. To stain your paper with a slight reddish or yellowish tint, adds to the harmony of a sketch, yet it is a mere matter of taste; but, when it is desired, it had better be done after the drawing is completed, otherwise the colour risks looking patched from the rubber.[6]
19. In colouring, the sky gives the ruling tint to the landscape; it is absurd to unite a noonday sky, with a landscape of sunset glow.
20. From the three virgin colours, red, blue, and yellow, all the tints of nature are composed.[7] There is not in nature a perfect white, except snow, and the petals of some flowers.
21. Sketch nothing but what you can adorn, (for the purpose of showing to friends, &c.) but do not adorn your first, or rough sketch; make another, and refer to your original draught, as you would do to the view itself, for it contains your general ideas—your first and freshest, which may be lost by endeavouring to refine and improve upon them in the original sketch.[8]
22. In adorning your sketch, figures, both animate and inanimate, may be introduced, but sparingly; touch them slightly, for an attempt at finish offends.