The theory of the three or seven colours being all equally necessary to each other, which has been derived from the division of the ray of light by a prism, has been supposed to afford the relative proportions of the various tints necessary to Harmony in a picture, because existing in light; and fanciful, but entirely unfounded, analogies have been drawn by enthusiasts between the seven colours and the seven notes, and the three colours and the notes of the common chord in music: but without going into the question of how far this would be likely to assist in our present inquiry, if true, it may be sufficient to observe that these relative proportions vary with the substance of the prism by means of which the ray of light is divided; so that the whole induction falls to the ground.
But were the proportions always the same, the induction would be equally untenable. For, though light may be very beautiful; and the Rainbow may be very beautiful; a totally different kind of beauty is required for a picture. The colours of the Rainbow may perfectly harmonize; but it is more than doubtful whether the person whose whole picture was a representation of a Rainbow, would be considered to have produced a finely coloured work of Art.
Harmony, in Pictorial Colour, does not depend upon any particular proportionate quantities of the different tints; nor in any particular disposition or arrangement of them; but upon the qualities and the treatment of the individual colours. A picture may be painted with every variety of the most brilliant colours; or, on the other hand, as Rembrandt treated light, the work may contain only one small spark of colour, the remainder being made up of neutral tints; and even the small spark of colour may be dispensed with, and the whole picture be made up of a variety of tones.
Having dwelt so much in the Sketcher's Manual, upon the principle of Breadth being indispensable for the production of Pictorial Effect, it will scarcely be requisite to point out that it is equally necessary that Colours should be so treated as to produce Unity; and that, as with lights and shadows, so whatever variety of tints may be introduced into a picture, they must be so blended and incorporated with each other, that they still form parts of a whole;—that whether the lights be white, and the shadows black, or differently coloured, the same necessity for graduation remains; so that Colours must not be in flat patches. And in the treatment of Colours, besides the graduation requisite for Breadth of Chiaroscuro, it is necessary to pay attention to the peculiar quality termed Tone, which is indispensable in a coloured Work of Art.
As well as Breadth of Chiaroscuro, there must be Breadth of Tone, the fundamental quality of Harmony.
CHAPTER I.
SECTION II.
TONE.
This is a term also borrowed from the vocabulary of Music, to denote a property or quality of Colour, the opposite of gaudiness or harshness; and implies a richness or sobriety, inviting quiet contemplation. It confers what is technically termed repose. It bears that relation to colours in general, that the quality of a musical note does to that of an unmusical sound or mere noise. In Music, this is known to depend upon the vibrations of the air being isochronous, or at regular intervals. Should it be discovered that Colours are also produced by vibrations, Tone in its present application may prove to arise from a similar regularity.