It is not desirable that I occupy space with diagrams of these quantities, but the industrious student will prepare them for himself, and will strive to realise a true half-tint, quarter-tint, etc., which is not a very easy thing to do. By practice, however, it will readily be accomplished, and anything achieved is a new power gained.
What I have said respecting the harmony of blue with tints of orange will apply in all similar cases. Thus red will harmonise with tints of green, provided the area of the tint be increased as the intensity is decreased; and so will yellow harmonise with tints of purple under similar conditions.
But we may reverse the conditions, and lower the primary to a tint retaining the secondary in its intensity. Thus blue, if reduced to a half-tint, will harmonise with orange of prismatic intensity in the proportion of sixteen of blue to eight of orange; or, if reduced to a quarter-tint, in the proportion o£ thirty-two of blue to eight of orange. Red, if reduced to a half-tint, will harmonise in the proportion of ten red to eleven of green; and yellow as a half-tint in the proportion of six yellow to thirteen of purple.
The same remarks might be made respecting the harmony of shades of colour with colours of prismatic intensity. Thus, if orange is diluted to a shade of half intensity with black, it will harmonise with pure blue in the proportion of sixteen of orange to eight of blue, and so on, just as in the case of tints; and this principle applies to the harmony of all hues of colour also.
To go one step further: we scarcely ever deal with pure colours or their shades or tints, or even come as near them as we can. With great intensity of colour we seem to require an ethereal character, such as we have in those of light; but our pigments are coarse and earthy—they are too real-looking, and are not ethereal—they may be said to be corporeal rather than spiritual in character. For this reason we have to avoid the use of our purest pigments in such quantities as render their poverty of nature manifest, and to use for large surfaces such tints as, through their subtlety of composition, interest and please. A tint the composition of which is not apparent is always preferable to one of more obvious formation. Thus we are led to use tints which are subtly formed, and such as please by their newness and bewilder by the intricacy of formation.
To do what I here mean it is not necessary that many pigments be mixed together in order to the formation of a tint. The effect of which I speak can frequently be got by two well-chosen pigments. Thus a fine series of low-toned shades can be produced by mixing together middle-chrome and brown-lake in various proportions, and in all of the shades thus formed the three primary colours will be represented, but in some yellow will predominate, and in others red; while in many it will not be easy to discover to what proportionate extent the three primary colours are present.
Let us suppose that we make a tint by adding white to cobalt blue. This blue contains a small amount of yellow, and is a slightly green blue. But to this tint we add a small amount of raw umber with the view of imparting a greyness[15] or atmospheric character. Raw umber is a neutral colour, leaning slightly to yellow—that is, it consists of red, blue, and yellow, with a slight excess of the latter. In order that an orange harmonise with this grey-blue of a slightly yellow tone, the orange must be slightly inclined to red, so as to form the complement of the little green formed by the yellow in the blue. It may harmonise with the grey-blue as a pure tint if the area of the diluted and neutralised primary is sufficiently extended, or may itself be likewise reduced to a tint of the same depth, when both tints would have the same area.
I might go on multiplying cases of this character to almost any extent, but these I leave the student to work out for himself, and pass to notice that while it is desirable to use subtle tints (often called "broken tints") it is rarely expedient to make up the full harmony by a large area of a tertiary tone and a single positive colour. Thus, we might have a shade or a tint of citrine spreading over a large surface as a ground on which we wished to place a figure. This figure would harmonise in pure purple were it of a certain size, and yet if thus coloured it would give a somewhat common-place effect when finished, for the harmony would be too simple and obvious. It would be much better to have the nineteen parts of citrine reduced, say, to half intensity, when the area would be increased to thirty-eight, with the figure of eight parts of blue and five of red, than of thirteen parts of purple.
But it would be better still if there were the thirty-eight parts of reduced citrine, three parts of pure yellow, thirteen of purple, five of red, and eight of blue, together with white, black, or gold, or all three (these may be added without altering the conditions, as all act as neutrals), for here the harmony is of a more subtle character.
If we count up the equivalents of the colours employed in this scheme of harmony, we shall see that we have, in the citrine—