MEASUREMENT, ACTUAL AND COMPARATIVE.
By actual measurement is meant the measurement of the object itself by
holding against it a ruler or straight strip of paper, and marking off
the number of inches or exact distance from one given point to another.
These measurements are then compared with the drawing, and the same
distances are marked off on the paper.
In mechanical and architectural drawing this system of measurement is
in constant use, but in freehand drawing, and in the method practiced
by artists, actual measurement is not allowed. Never measure in any way
when beginning a drawing, but strike out bravely, resolving to depend
upon the eye only, if possible.
After the first outlines are put in, and the proportions are as nearly
correct as you can make them, it is perfectly legitimate to “prove” a
drawing by actual measurement, if it is a copy. If one is drawing from
a cast, or from life, and it is necessary that the head be exactly the
same size, a measurement may be taken from the top of the head to the
chin, and compared with the sketch you have made. Beyond this no actual
measurement should be allowed.
COMPARATIVE MEASUREMENT.
This is a very important thing in drawing from Nature, or objects of
any kind, and must be thoroughly understood by the student, as without
it no drawing can be made absolutely correct.
Comparative measurements are entirely _proportional_. The manner of
taking them is as follows:
Place yourself opposite the object to be measured, at the same distance
from which your drawing is taken. Let us say you are drawing the bust
of Apollo, and wish to discover just the exact height of the whole,
also the width across the shoulders.
Extend your arm in a perfectly straight line at right angles to the
cast, holding in your hand a long lead-pencil. The pencil must be
held parallel to the general direction of the cast, neither end being
allowed to swerve the slightest.
Now, closing one eye to concentrate the vision, measure off with your
thumb upon the pencil, which is held crosswise, the apparent distance
from the outside of one shoulder in a direct line to the outside of the
other. Keep your thumb tightly upon the pencil at the place measured,
and slowly turn the hand around, keeping the arm extended at the same
distance from the body, and the eye in the same position as before.
The pencil is now held straight up and down, and your object is to
see how many times the distance measured off on the pencil will go
into the whole length of the cast, beginning at the top of the head
and measuring down to the foot of the bust, slowly moving the pencil
downward and checking off with the eye each time the measurement is
repeated.
In this way we can find out exactly whether the cast is just twice as
long as it is wide, or less—in other words, the comparative proportions.
This kind of measurement is invaluable in out-of-door sketching, and
the eye soon becomes so trained by practice that relative proportions
are compared instinctively, and one scarcely needs to use the pencil.
THE PLUMB LINE.
Another most valuable adjunct in drawing from life and from the cast is
the plumb line. This consists of a piece of strong twine with a weight
on one end, which serves to keep the string perfectly straight and
steady when suspended from the hand. A straight line is thus simulated
which is dropped from a given point to one directly underneath,
forming one side of a triangle, which will ascertain for us the
different positions that certain other parts assume in relation to this
line.
For instance, we hold the plumb line so as to make a straight line from
the chin of a standing figure to the ground. The top and bottom of the
line form two points of a triangle, the third to be represented by the
man’s heel.
Imaginary lines are now drawn through these points, forming the
triangle, whose base determines the direction of the heel in relation
to the center-line of the body. In this way the balance of a figure
can be accurately ascertained, and the most difficult action correctly
suggested.
In the actual drawing the real lines may be sketched in charcoal from
point to point at the same angle determined by the plumb, and the
corrections made accordingly, these straight lines being of course
erased afterward.
VALUES.
The term “value,” as understood by artists, is used to express the
_comparative relation of tones to each other_, irrespective of color.
There may be many different colors before us all of the same value;
also, there may be only one color used in a drawing, yet many different
values are seen, which goes to show that we are to compare tones and
not colors.
For example, in drawing or painting a landscape we look at the tone of
the trees against the sky and observe which is the darker. If a stormy,
heavy sky is seen behind light, feathery, green trees we see that the
sky is darker in value.
If, on the contrary, trees with dark, rich foliage are observed to be
strongly relieved against a bright, sunny sky, we perceive at once
that the sky is lighter in value than the trees. In like manner we
compare the rocks with the water, the fence with the road, and so on,
according to the different objects to be regarded in the picture.
In drawing a head in charcoal or crayon it is well to establish at once
the darkest value in the whole, selecting the deepest spot of shadow
with which all the other tones of dark may be compared.
Look for instance, at the shadow over the eye or under the nose, which
are generally very dark, and compare it with the shadow on the cheek,
behind the ear, or under the chin. In the same way decide upon the
highest light in the face. Say it is found upon the forehead or on the
cheek bone. Be sure that it is the brightest spot in the face, and then
compare all the other degrees of light with this.
By studying in this way, and observing the comparative variety of these
tones, we arrive at correct values.
This is a most important quality in art and can not be overestimated,
for upon a just appreciation of the values in a picture depends its
truth. This also serves to illustrate the necessity of making studies
directly from nature whenever possible.