If the sky is to be blue, wash it all over with a weak solution of blue; if there are white clouds, you can touch up the highest lights with Chinese white; if there is a sunset or rosy effect, use a weak solution of rose or a little magenta. But it is best not to try to make too much of the sky, as the gray that is generally in it will give a very pretty effect and leave more contrast between the figures and the sky. For the middle distance mix blue, rose, and a little yellow or gold if you want it greenish, or you can use a very little brown. The nearer the trees come in the foreground the stronger in color they should be; that is, they should tend more to the green and brown and less to the bluish color. If they are to be bright green use blue and yellow, and retouch the light places with yellow. You can make the green duller by mixing a little black with the yellow, or you can make a richer green by using blue, gold and brown, and then touching up the lights with gold, and the shadows with brown. For the grass use blue and yellow, and retouch the lights with yellow; for the ground use brown, and retouch the lights with gold; for tree trunks, fences, and the like, use brown; for rocks, use black and a little brown.