The Painter in oil

It is not my province to say whose colors you should use; doubtless there are many
colorman who make artists’ materials honestly and well. Nevertheless, I may mention
that they 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 manufactures do not make any colors which should not go on
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 were 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 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; 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 with 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.