The Painter in oil

Study your original carefully before and while working on your own canvas. See how it
was done if you can and you can, do it in the same way, touch for touch, stroke for
stroke, color for color. Use a large brush when he used a large brush; if the original was
done with a palette knife, use yours; and particularly never use a smaller brush than the
painter used on the picture you are copying.
The same thing holds as to processes. If your original is painted solidly, with full-
bodied color, do so on your copy. Never glaze nor scumble because you can’t get the
colors without. Your business is to try to get the same qualities in the same way. And
any other manipulation is not only getting a different thing, but shirking the problem.
Because, if you can’t get the effect in the same way he did, you certainly won’t get the
same one any other way. You are not originating, you are not painting a picture, you are
copying another man’s work; and common honesty to him, as well as what you are trying
to learn, demands that you shall not belie him by stating on your canvas implicitly, that
he did the thing one way, when as a matter of fact his canvas shows that he did it another
way.
This may seem commonplace, because one would think that as a matter of course any
one would naturally make a copy this way. But this is precisely what the average person
does not do when copying, and I have found constantly necessary to insist upon these
very points even to advanced students.
So in the pigments, the vehicles, the tools, and even the canvas if you can, as well as in
the handling of the paint and the processes used, follow absolutely and humbly, but
intelligently, the workmanship of the picture you copy, if it is worth your while to do it
all.
In making copies it is not usual to make the preliminary drawing freehand. It takes
time that may better be given to something else, and often it is not exact enough. When a
painter has made careful studies which he wishes to transfer to his canvas, they may
have qualities of line or movement, or of emphasis or character which the model may
not have had. These studies, probably, are much smaller than they will be in the picture.
The same things may be true of the characteristics of the sketches. These are problems
which have been worked out, and to copy them freehand makes the work to be done over
again on a larger scale on the canvas of the picture.
This would not only take too much time, but the same result might not follow. For this
purpose a more mechanical process is commonly made use of, which combines the
qualities of exactness with a certain freedom of hand, without the work would be too
rigid and hard.
“Squaring up.” - This process is called “squaring-up,” and consists of making a
network of squares which cut up the study, and map out its lines and proportions, and
make it possible to be sure that any part of the original will come in the same relative
place in the copy no the matter what the size may be, and at the same time leaves the
actual laying out of the thing to freehand drawing.
The process is a very simple one. You marl off a number of points horizontally and
vertically on the study. Make as many as you think best - if there are too few, you will
have too much of the study in one part; if too many, it makes you more trouble. It is not
necessary that there be as many points one-way as the other; make the number to suit
the lines of the study.