The Painter in oil

But if you are in touch with your century, if you would paint to express the suggestion
you receive from nature you study, or if you would convey the idea of truth to the world
around you, as that world exists, frankly accepting the conditions of it, you will have to
make the study of values fundamental to your work.
“The Fourth Dimension.” - You study values with your eyes only, but you cannot
measure values. Length, breadth, and thickness you can measure; but values constitute
what might be called a “Fourth Dimension,” and you must measure it by your eye, and
without any mechanical aid. Your eye must be trained to distinguish and judge
differences of value.
Helps. - There are, however, several things which you can use to help you in training
your eye to distinguish values. When you look for values you do no wish to see details
nor things, you wish to see only masses and relations. You must unfocus your eye. The
focussed eye sees the fact, and not the relation. Anything which will help you to see
outlines and details less distinctly will help you to see the values more distinctly.
Half-closed Eyes. - The most common ways to have close the eyes, which shuts out
details, but permits you to see the values. Some painters think this falsifies pitch, and
prefer to keep the eyes wide open, but to focus them on some point beyond the values
they are studying. This is not so easy to do as to have close the eyes, but becomes less
difficult with practice.
The Blur Glass. - An ordinary magnifying-glass of about 15-inch focus, which you
can get at an optician’s for fifteen or twenty cents, will blur the details, and help you to
see the values, because it makes everything vague except the masses. You can frame it for
use by putting it between two pieces of cardboard with a hole in them, or you can do the
same with two pieces of leather sewed around the edge. Of course the glass itself is all
you need, but it will be easily broken if unprotected.
Do not try to look through the glass at your subject, but at the glass and the image on
it.
The Claude Loraine Mirror. - This is a curved mirror with a black reflecting
surface. The object is reflected on it, reduced both in size and pitch. It concentrates the
masses and the color, and so helps to distinguish the relative values.
You can make a mirror of this sort for yourself by painting the back of a piece of plate
glass black. The real Clause Loraine mirror is expensive.
The Common Mirror is also very helpful in distinguishing values. It reduces the size of
things, and reverses the drawing that you see your subject under different conditions,
and a fresh eye is the result. Place the group and your painting side by side, if you are
painting still life, and look at both at the same time in the mirror. Do the same with a
portrait and the sitter.
Diminishing Glass. - Much the same effect can be had by using a double concave
lens. The picture is not reversed, but it is reduced, and the details eliminated.
In using any of these means you must remember that it is always the relations and not
the things you are studying; and the most useful of these aids is the blur glass, because
you cannot possibly see anything in it but the values and color masses, everything else
being blurred.