A picture is made up of many elements. Certain of them are essentially abstract. They must be thought out by a sort of mental vision without words. This is the most subtle and intimate part of the picture. These are the means by which the ideal is brought into the picture.

Line, Mass, and Color.—Such are the qualities of line, dissociated from representation; of mass, not as representing external forms; and color, considered as a quality, not as yet expressed visibly in pigment, nor representing the color of any thing. When these elements are combined they may make up such conceptions as proportion, rhythm, repetition, and balance, with all the modifications that may come from still further combination.

It is because these elements are qualities in themselves beautiful that actual objects not beautiful may be made so in a painting, by being treated as color or line or mass, and so given place on the canvas, rather than as being of themselves interesting. A face, for instance, may be ugly as a face, yet be beautiful as color or light and shade in the picture. These qualities, I say, do not represent—they do not necessarily even exist, except in the mind to which they are the terms of its thought. Nevertheless, they are the soul of the picture. For whatever the subject, or the objects chosen for representation, it is by working out combinations of these elements, through and by means of those objects, that the picture really is made.

The picture, as a work of art, is not the representation of objects making up a subject, but a fabric woven of color, line, and mass; of form, proportion, balance, rhythm, and movement, expressed through those actual objects in the picture which give it visible form.

I do not purpose to go deeply into these matters here. Elsewhere, as they bear practically on the subject in hand, as in the chapters on "Composition" and on "Color," I shall speak of them more fully. But I wish here to call attention to this abstract side of painting in order to show the relation between the two classes of things, the one abstract and the other concrete, which together are needed to make up a picture.

The concrete, or material, part of a picture includes all those things which you can look at or feel on the canvas; and by seeing which you can also see the abstract qualities, which do not visibly exist until made visible through the disposition of these tangible things, on the canvas. Beyond this is included all the technical qualities of expression; form, as drawing; all representations of objects; the pigment by means of which color is seen; and all those technical processes which produce the various kinds of surface in the putting on of paint, and bring about the different effects of light and shade and color, form or accent.

In learning to paint, it is with these concrete things that you should concern yourself mainly. The science of painting consists in the knowledge of how to be the master of all the practical means of the craft. For it is with these that you must work, with these you must express yourself. These are the tools of your trade. They are the words of your art language—the language itself being the abstract elements—and the thoughts, the combinations which you may conceive in your brain by means of these abstract elements.

You must have absolute command of these materials of painting. No matter how ideal your thought may be, no matter how fine your feeling for line and color and composition, if you do not know how to handle the gross material which is the only medium by which this can all be made visible and recognizable to another person, you will fail of either expressing yourself, or of representing anything else.

Now you will see what I have been driving at all this time; why I have been talking in terms which may well be called not practical. I want to fix your attention on the fact that there are two qualities in a picture: that one will be always within you, mainly, and will control the character of your picture, because it will be the expression of your mental self; and the other the practical part, which any one may, and all painters must learn, because it is the only means of getting the first into existence.

The one, the abstract part, no one can tell you how to cultivate nor how to use. If I tried to do so, it would be my idea and not yours which would result. I can only tell you that it is the thought of art, and you must think your own thoughts.

But the other, the material, the concrete, the practical, it is the purpose of this whole book to help you to understand and to acquire the mastery of, so far as may be done by words.

Teaching by words is difficult, and never completely satisfactory. But much may be done. If you will use your own brains, so that what does not seem clear at first may come to have a meaning because of your thinking about it, we may accomplish a great deal. I cannot make you paint. I cannot make you understand. I can give you the principles, but you must apply them and think them out. Everything I say must be in a measure general; for the needs of every one are individual, and the requirement of each technical problem is individual. I must speak for all, and not to any one. Yet I shall state principles which can always be made to apply to each single need, and I will try to show how the application may be made.

Technique.—The science of painting consists of a variety of processes by means of which a canvas is covered with pigment, and various objects are represented thereon. The whole body of method and means is called technique; the several parts of technique are called by names of their own. That part which applies to the putting on of the paint may be generally called handling, although the word painting is sometimes restricted to this sense, and brush-work is often used for the same thing. The other technical means will be spoken of in their proper place. Let me say now a few words as to handling in general.

Where did all this technique come from?

From experiment.

Ever since art began, men have been searching for means of fixing ideas upon surfaces. But it is only within the last four hundred years that the processes of oil painting have been in existence—simply because they are peculiar to the use of pigments ground in oil as a vehicle, and the oil medium was not invented until the middle of the fifteenth century.

With the invention of this medium new possibilities came into the world, and a continual succession of painters have been inventing ways of putting on paint, the result being the stock of methods and processes of handling which are the groundwork of the art of painting to-day.

From time to time there have been groups of artists who have used common methods, and who have developed expression through those methods which became characteristic of their epoch; and because the resulting pictures were of a high degree of perfection, their methods of handling acquired an authority which had a very determining effect on different periods of painting.

In this way have come those ideas as to what kind of painting or what ways of putting paint on canvas should be accepted as "legitimate." And the methods accepted as legitimate or condemned as illegitimate have been varied from time to time—those condemned by one period being advocated by another; and the processes themselves have been almost as varied as the periods or groups of men using them.

In the long run, methods and processes have received such authoritative sanction from having been each and all used by undoubted masters, that they have become the traditional property of all art, which any one is free to use as he finds need of them. They have become the stock in trade of the craft.

The artist may use them as he will, provided only he will take the trouble to understand them. He must understand them, because the manipulations which make up these different processes accomplish different effects and different qualities; and as the painter aims at results, if he does not understand the result of a process when he uses it, he will get a different one from that which he intended.

The painter should not be hampered by process; he should not be controlled in the expression of himself by tradition. He should feel free to use any or all means to bring about the result he aims at, and he should allow no tradition or point of view to prevent him from selecting whichever means will most surely or satisfactorily bring about his true purpose.

Of course there are many ways of using paint which are unsafe. Some pigments are unsafe to use because they either do not hold their own color, or tend to destroy the color of others. You should always bear this in mind; and if you care for the permanence of your work, you should not use such materials or such processes as work against it. But beyond this, the whole range of the experience and experiment of the workers who have gone before you are at your command, to help you to express yourself most perfectly or completely; to represent whatever of visible beauty you may conceive or perceive.

And this is the whole aim of the painter; to stand for this is the whole purpose of the picture.