The Painter in Oil. Daniel Burleigh Parkhurst
have to do with the business of drying, owing to the substances used as dryers, but they may have to do with the chemical action of one pigment on another.
The Preparation.—Finally, the preparation of the pigment demands the utmost skill and knowledge, if the colors are to be good. The paints used by the old masters were few and simple, and the fact that they prepared them themselves had much to do with the manner in which they kept their color. The paints used now are less simple. We do not prepare and grind them ourselves, and we could hardly do so if we wished to, so we are the more dependent on the integrity of the colorman who does it for us.
The preparation of the paint begins with the chemical or physical preparation of each pigment, and then comes the mixing of several to produce any particular color; and finally the mechanical process of grinding with the proper vehicle to bring it to the proper fineness and smoothness.
Grinding.—The color which the artist uses must be most evenly and perfectly ground. The grinding which will do for ordinary house paints will not do for the artist's colors. Neither will the chemical processes suitable for the one serve for the other. Not only must the machinery, but the experience, skill and care, be much greater for artist's colors. Therefore it is that the specialization of color-making is most important to good colors for the use of the artist.
Reliable Makers.—If you would work to the best advantage as far as your colors are concerned, both as to getting the best effects which pure pigments skilfully and honestly prepared will give you, and as to the permanency of those effects when you have gotten them, see to it that you get paint made by a thoroughly reliable colorman.
It is not my province to say whose colors you should use; doubtless there are many colormen who make artists' materials honestly and well. Nevertheless, I may mention that there are no colors which have been more thoroughly tested, both by the length of time they have been in the possession of painters, and by the number of painters who have used them, than those of Winsor and Newton of London. No colors have been so generally sold and for so long a time, particularly in this country, as these, and none are so well known for their evenness and excellence of quality.
I do not say that these manufacturers do not make any colors which should not go on the palette of the cautious artist—I believe that they do not make that claim themselves; but such colors as they do assert to be good, pure, and permanent, you may feel perfectly safe in using, and be sure that they are as well made as colors can be. This is as much as can be said of any paints, and more than can be said of most. I have used these colors for many years, and my own experience is that they have always been all that a painter need ask.
The fact that Winsor and Newton's colors can be found in any town where colors can be had at all, makes me the more free to recommend them, as you can always command them. This fact also speaks for the general approval of them.
Inasmuch as certain colors are not claimed to be permanent and others are, it is for you to compose your palette of those which will combine safely. This you can do with a little care. Some colors are permanent by themselves or with some colors, but not in combination with certain others. You should then take the trouble to consider these chemical relationships.
It is not necessary for you to study the chemistry of paints, but you may read what has been ascertained as to the effects of combinations, and act accordingly. There are practically duplications of color-quality in pigments which are bad, and in pigments which are good; so that you can use the good color instead of the bad one to do the same work. The good color will cost more, but there is no way of making the bad color good, so you must pay the difference due to the cost of the better material, or put up with the result of using bad colors.
Chemical Changes.—The causes of change of color in pigments are of four kinds, all of them chemical effects. 1, the action of light; 2, the action of the atmosphere; 3, the action of the medium; and 4, the action of the pigments themselves on each other. The action of light is to bring about or to assist in the decomposition of the pigment. It is less marked in oil than in water color, because the oil forms a sort of sheath for the color particles. The manner in which light does its deteriorating work is somewhat similar to that of heat. The action of light is very slow, but it seems to do the same thing in a long time that heat would do in a short time.
Some colors are unaffected or little affected by light, and of course you will use them in preference to all others. The atmosphere affects the paint because of certain chemical elements contained in it, which tend to cause new combinations with the materials which are already in combination in the pigment. The action of the oxygen in the air is the chief agent in affecting the pigment, and it is here particularly that light, and especially sunlight, assists in decomposition. The air of towns and cities generally contains sulphuric and sulphurous acids and sulphuretted hydrogen. This latter gas is most effective in changing oil paintings, because of its action in turning white lead dark; and as white lead is the basis of many qualities in painting, this gas may have a very general action.
Moisture in the atmosphere is also a cause of change, but there is little to be dreaded from this, as the oil protects the colors.
Oil absorbs oxygen in drying, and so is apt to have an effect on colors liable to change from that element, and many vehicles contain materials to hasten the drying which further aid in the deterioration of the pigment. Bad oil will tend to crack the picture also. The greatest care should be used in this direction, as the most permanent colors may be ruined by bad vehicles.
Pigments will not have a deteriorating effect on each other as long as they are solid. But if one of them is soluble in the medium, then chemical action commences; but as most pigments are somewhat soluble, there is always some danger in mixing them. The best we can do is, as I said before, to try to have on the palette, as far as possible, only colors which are friendly to each other.
As a student you should not be much occupied, however, with all this. You must expect that all color will change somewhat. But you need not use those which change immediately or markedly, and you may use them in a way which will tend to make them change as little as may be. Colors have stood for years, and what is practical permanence, not perfect permanence, is all you need look for. If you think too much of the permanence of your colors, it will interfere with the directness of your study. Therefore, decide on a palette which is as complete and safe as you can make it, excluding the notably bad pigments, and think no more about it.
When you need to add a new color to your palette, choose it with reference to those already on it, and go ahead. This is what the whole subject resolves itself to, practically, for you as a student.
Opaque and Transparent Colors.—Some colors, like the madders, have a jelly-like consistency when mixed with oil, others, the earths among them, are dense and opaque. We speak of them respectively as "transparent" and "solid" colors. These qualities, which divide the paints into two classes, have no relation to their permanency. As far as that is concerned you use them in the same way, as some transparent colors are safe and some fugitive; and the same with the opaque colors.
The only difference is in the fact that, as a rule, the solid colors are better dryers. But you will notice that while you may mix these colors together as though this difference between them did not exist, in certain processes you use them differently. So you will see, farther on, that for a "glaze" you can use only the transparent or semi-opaque colors, for a scumble you naturally use the solid ones. You should know, however, for the sake of clearness, just what is meant when "solid" or "body" or "opaque" color is spoken of, and what is meant by "transparent" color.
Safe and Unsafe Colors.—Beyond what has been said of the causes of change in colors it is not necessary that you should know the chemical constituents of them. If you want to look into the matter further there are books, such as "Field's Chromatography," which treat fully of the subject, and which you may study.
But practically you should know which colors are to be depended on and which not. Let us consider the principal colors in detail then, merely as to their actual stability. I will speak of them in connection with the plates of colors at the end of this book. I would like you to compare what is said of each color with