The great painters of the earlier school have consequently as a rule made little use of such contrasts or specific schemes of lighting. And they did rightly, inasmuch as their emphasis was rather on the spiritual aspect as such than on the sensuous impression of their pictures. And on account of the pre-eminent ideality and spiritual significance of the content they were able to dispense with the aspect of their work which inclined more or less to the material side. In the case of landscapes, on the contrary, and subjects of less importance taken from ordinary life, the question of lighting makes a very different appeal. In these important artistic and, often, artificial and mysterious effects are indispensable. In the landscape the bold contrasts between large masses in illumination and other parts in the strongest shadow will receive their full effect, but tend also to develop the artistic mannerism. Conversely we find, more especially in the treatment of landscape, reflections of light, the flash and its counterfeit, that wonderful echo of light, which arises from the interplay of light and dark, and offers an ample and progressive subject of study both to the artist and the spectator. Such a scheme of lighting, which the artist has either by direct imitation or imaginatively conceived in his work, can, however, by itself only be a transient one, which is subject to rapid change. However sudden or uncommon the lighting thus permanently retained may be, the artist must see in the treatment of his composition, even though it be as full of movement as possible, that the whole, despite all its variety, is not injured by mere restlessness and wavering motive, but is throughout clear and marked with unity.
(_ββ_) In accordance with what has already been stated the art of painting, however, has not merely to express light and dark in its purely abstract intension, but to add to it the distinctions of colour. Light and shadow must be coloured light and shadow. We have therefore in the _second_ place to discuss colour simply.