61. A line attracts attention in the measure of the tone-contrast which
it makes with the ground-tone upon which it is drawn. It attracts
attention, also, according to its length, which is an extension of the
tone-contrast. It attracts more attention the longer it is, provided it
lies, all of it, well within the field of vision. It attracts attention
also in the measure of its concentration.
[Illustration: Fig. 63]
Line “a” would attract less attention than it does if the
tone-contrast, black on a ground of white paper, were diminished,
if the line were gray, not black. In line “b” there is twice the
extension of tone-contrast there is in “a.” For that reason “b” is more
attractive. If, however, “a” were black and “b” were gray, “a” might be
more attractive than “b,” because of the greater tone-contrast.
[Illustration: Fig. 64]
In this illustration the curved line is more attractive than the
straight line because it is more concentrated, therefore more definite.
The extent of tone-contrast is the same, the lines being of the same
length.
[Illustration: Fig. 65]
In this line there is no doubt as to the greater attraction of the
twisted end, on account of the greater concentration it exhibits.
The extent of tone-contrast is the same at both ends. The force of
attraction in the twisted end of the line would be diminished if the
twisted end were made gray instead of black. The pull of concentration
at one end might, conceivably, be perfectly neutralized by the pull of
a greater tone-contrast at the other.
[Illustration: Fig. 66]
In “b” we have a greater extension of tone-contrast in a given space.
The space becomes more attractive in consequence.
This might not be the case, however, if the greater extension
of tone-contrast in one case were neutralized by an increase of
tone-contrast in the other.