Howard, Frank: Colour, as a means of art: being an adaptation of the experience of professors to the practice of amateurs (London, 1838)

30 TONE.

from texture in Oil: and the purity of the one art
is lost, without attaining the force of the other,
A crumbly, bungling appearance is produced, and
for no reason, as the practice can never be success-
fully employed in the parts or objects, in which the
use of semi-transparent colours is so invaluable in
Oil. And in fact, Opacity, the reverse of what is
desired, Tone, is produced by the very same means
in Water-colours, by which transparency is attained
in Oil.

Breadth of Tone is obtained by a process termed
breaking the colours, which is the same with the
method of incorporating lights with each other,
described in the Sketcher's Manual: viz. graduating
each tint into those adjacent, by which means a
certain degree of affinity is diffused throughout the
whole picture, and Harmony, or Breadth of Tone,
is produced. The same results are effected, by a
process perhaps abused in the present day, termed
Glazing, which consists in passing some transparent
pigment of the tone desired, over the whole picture,
and thus breaking all the tints in the work with
the same colour which produces the affinity required.