Don't get too many things into one landscape. The spirit of the time and place is what will make the beauty of it, not the details nor the mere facts. This spirit you will find in a few things, not in many. Having found which lines and forms, which masses and relations of color and value, express this, the more carefully you avoid putting in other things the more entirely you emphasize the quality which is the real reason of existence of your picture.
In studying landscape, work for one thing at a time. What has been said of sketching and studies applies here. Landscape is the most bewildering of subjects in its multiplicity of facts and objects and colors and contrasts. If you cannot find a way to simplify it you will neither know where to begin nor where to leave off. I cannot tell you just what to do or not to do, because no two landscapes are alike. Recipes will do nothing in helping you to paint. But there is the general principle which you may follow, and I try to keep it before you even at the risk of over-repetition. In no kind of picture can you drag in unimportant things simply because they exist in nature. In landscape more than elsewhere, because you cannot arrange it, but must select in the actual presence of everything, you must learn to concentrate on the things which mean most, and to refuse to recognize those which will not lend themselves to the central idea.
Selection.—When you select your subject, or "motif," as the French call it, select it for something definite. There is always something which makes you think this particular view will make a good picture. State to yourself what it is that you see in it, not in detail, but in the general. Is it the general color effect of the whole, or a contrast? Is it a sense of largeness and space, or a beautiful combination of line in the track of a road, or row of trees, or a river? Perhaps it is the mass and majesty of a mountain or a group of trees. Something definite or definable catches you—else you had better not do it at all; and what that something is you must know quite precisely, or you will not have a well-understood picture.
When you have distinctly in your mind what you want to paint it for, then see that the composition is so placed on your canvas that that characteristic is the main thing in evidence. With this done it is a very easy thing to concentrate on that characteristic, and to leave out whatever tends to break it up or distract from it. This is the only way you can simplify your subject. First by a distinct conception of what you paint it for, then by so much analysis of the whole field of vision as will show you what does and what does not help in the expression of it.
Detail.—Much detail in landscape is never good painting. Whether big or little, your canvas must express something larger and more important than detail. Give detail when it is needed to express character or to avoid slovenliness. Give as much detail where the emphasis lies as will insure the completeness of representation—not a touch more.
Structure.—Have your foreground details well understood in drawing and value. This does not require the drawing of leaf and twig, but it does require structure. Everything requires structure. Structure is fundamental to character. If you will not take the trouble to study the character of any least thing you put in, don't put it in at all. Nothing is important enough to put in, if it is not important enough to have its character and its purpose in the picture understood.
I spoke of structure in speaking of the head. If I said nothing but "structure, structure, structure" to the end of the section, you would get the impression of what is the most important thing in drawing. If you will look for and find the line and proportion expressing the anatomy which makes the thing fulfil its particular function in the world, you will understand its character, and that is what is important, everywhere.
Work in Season.—Make your picture in the season which it represents. I don't say that a good summer picture may not be made in winter; but I do say that you are more likely to express the summer quality while the summer is around you. There is too much half painting of pictures, and then leaving them to be "finished up" afterwards.
Of course you can make all your studies and sketches, and then begin and finish the picture from them. If you are careful to have plenty of material, to accumulate all your facts with the intention of working from those facts, all right; but it would be better if you were to work your picture in the season of it, as long as you are a student at least. For until you have had a great deal of experience, you will find when you come to paint your picture that some very much needed material you have neglected to collect, and you cannot safely supply it from memory. If this occurs in the time of year represented in the picture, you can just go out and study it.
Out-of-door Landscapes.—The most important movement in modern art, the most important in its effects on all kinds of work, is what I have mentioned as the plein air movement. It was thought by some clear-headed men that the best way to paint an out-door picture was to take their canvases out-of-doors to paint it. Instead of working from a few color sketches and many pencil studies, they painted the whole picture from first to last in the open air. Working in this way, certain qualities got into the pictures unavoidably. Necessarily the color was fresher and truer. Necessarily there was more breadth and frankness, and less conventionality and mere picture-making. The spirit of the open got onto the canvas, and the whole type of picture was changed. For the first time out-of-door values were studied as things in themselves interesting and important. The result on landscape pictures was that pictures painted in the studio seemed unreal and insincere, and that men looked and studied less for the making of pictures, and more for what nature had to reveal.