I have already observed that the very nature of the facts necessitates that colour should have itself an articulated system. And this complete result should appear. No fundamental colour should be wholly omitted, otherwise our sense of this integrated whole is lost. To an exceptional degree the old Italian masters and the Dutch satisfy us in this respect. We find in their pictures blue, yellow, red, and green[290]. It is this completeness which supplies the basis of our colour harmony. The colours, moreover, must be so arranged that not merely their artistic contrast, but also their mediation and resolution, and a repose and reconciliation as the result of such, is made visible to the sight. Such effective contrast and repose in conciliated extremes is brought about partly by the way the colours are associated, and partly by the degree of intensity which characterizes each colour. In early painting it was principally the Dutch school[291], which employed the cardinal colours in their purity and their unimpaired brilliance, by which means the harmony is rendered more difficult by reason of the emphasis laid on contrast, but when secured should be pleasing to the eye. Where, however, the decisive character and force of colour is insisted on the nature of the subject-matter itself should be more definite and simple. And by attending to this a higher degree of harmony between colouring and content is also obtained. The important personages, for instance, must receive the colour that is most emphatic, and in their characterization, their entire deportment and expression should appear more imposing than the subordinate figures, who will receive merely the composite colours. In landscape painting the contrast of pure cardinal colours is less pronounced. In scenes, on the contrary, in which human figures are of most importance, and more particularly where drapery occupies large spaces of canvas, the more simple colours will be in their right place. In such we have a scene taken from the world of spiritual life, in which that which is inorganic, the natural environment, is more abstract, in other words must not appear in its natural completeness and isolated manner of effect, and the varied tints of landscape in all the profusion of their gradations are less suitable. As a rule the landscape is not so entirely fitted to the environment of human scenes as a room, or generally that which is architectural, inasmuch as situations which take place in the open air are in general not accepted from a class in which the life of soul without considerable reserve is manifested. If a man is placed before us with the open landscape around him it should appear simply as environment. And in cases of this type it is right to make use of colours that are exceptionally prominent. But the use of such involves also boldness and power of execution. Sickly sweet, overpowered[292], doting faces are not the kind for such treatment.