A more distinct idea of light and shade is best obtained by the use of one colour only, as many only tend to perplex the eye, and divert the attention from the great object that should be distinctly kept in view.
In laying on the tints (of one colour only), the method to be pursued is as follows:—Mix the separate shades in separate saucers, three, four, or five, as may be required; keep the board you have previously strained the paper on inclined at moderate elevation, that the colour may flow freely; lay in the sky first; the farthest distance next; then all those masses of shadow which principally influence the division and interest of the picture; working downwards to the foreground from the middle distance, using a large brush, filled with colour, to produce clearness and transparency. Then proceed to delicately touch upon the lights, in order to blend them with the shadows, that they may not appear too abrupt, as well as to break down their asperity, and prevent the work looking bald. Now a darker shade than any should be mixed up, to put in the markings of the foliage and foreground, rocks, or whatever the composition may consist of. Lay the whole on with freedom and boldness; and, if any parts require strength, they may be lightly floated over again, when quite dry.
Do not disturb the surface of the paper more than can be avoided; and endeavour to keep all the tints even, or flat, in the first instance, without attention to the details. Always mind to take up enough of the colour at once to cover down the space intended, without sweeping it contrary ways. Thick rough paper is the best.
The power of making large masses of flat tints, commonly comes of great practice; it is, therefore, necessary that this difficulty is conquered, before attempting to blend them.
The use of that important thing, in the hands of an artist, the sponge, must be taught and seen to be understood.
The most forcible arrangement in the composition of light and shade is, where it is spread and diffused, until reaching the strongest point; which point, opposed immediately to the most retiring part, and clothed in strong colour, will have the effect of balancing and combining the most complicated forms, that, but for this method, had been all confusion.
If a sketch be too outliny, it will want solidity; if too much filled in, it will be heavy.
Do not let the lights be too scattered, or too equal, lest the struggle for precedence be observed.
When clouds are interposed between the sun and the object, the shadows will be soft, and their terminations almost imperceptible.