t is a substitution of the study of _relation_ for the study of
_contrast_.

=Study of Values.=--You see at once how important, how vital, the
study of values is to painting. Even if you paint with arbitrary
lighting, as is still done by many painters, especially in portraits,
you have to consider and study them as they apply to _parts_ of your
picture. You will find no good painter of old time who did not study
relations. If you look at a Velasquez, you will find that he knew
values, even though he did not use the word.

But if you are in touch with your century, if you would paint to
express the suggestion you receive from the 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 not 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 way is to half 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 half 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