Linear perspective is connected in the first instance merely with the different degrees of size, which the lines of objects possess in their greater or less remoteness from the human eye. This alteration and reduction of form is, however, not the only thing painting has to reproduce. In Nature everything is affected by the presence of atmosphere, not merely between different objects, but even different parts of them, a difference which asserts itself in colour. This tone of colour which thus as it were evaporates with the distance is what constitutes _atmospheric perspective_, in so far as thereby objects are modified partly in deliberate outline, and partly in respect to their light and shadow and general colouring. As a rule people think that what is nearest to the eye in the foreground is brightest, and what lies in the background is more obscure; in truth the matter is otherwise[295]. But lights and shadows in the foreground are strongest, in other words the contrast between light and shade has a more powerful effect, and outlines are more defined near to the spectator. In proportion, however, to the degree of their remoteness, they lose in definition of colour and form, because the contrast of their light and shadow is gradually reduced, until finally everything disappears in transpicuous gray. Different schemes of lighting, however, necessitate in this respect various modes of treatment. In landscape painting more especially, but also in other compositions, which present large spaces, atmospheric perspective is of first importance, and the great masters of colour have carried out by this means the most bewitching effects.