The ideal, for the man who is quite coarsely realistic in his figures, exists in the air, light, colour; and in saying this I have, so to speak, turned over the page too quickly, forestalled the expression of what I can prove only later: the disconnection of such comparative realism and idealism as this (the only kind of realism, let us remember, which can exist in great art) with any personal bias of the artist, its intimate dependence upon the constitution and tendency of art, upon its preoccupations about form, or colour, or light, in a given country and at a given moment. And now I should wish to resume the more orderly treatment of the subject, which will lead us in time to the second half of the question respecting realism and idealism. These considerations have come to me in connection with the portrait art of the Renaissance; and this very simply. For portrait is a curious bastard of art, sprung on the one side from a desire which is not artistic, nay, if anything, opposed to the whole nature and function of art: the desire for the mere likeness of an individual. The union with this interloping tendency, so foreign to the whole aristocratic temper of art, has produced portrait; and by the position of this hybrid, or at least far from regularly bred creature; by the amount of the real artistic quality of beauty which it is permitted to retain by the various schools of art, we can, even as by the treatment of similar social interlopers we can estimate the necessities and tendencies of various states of society, judge what are the conditions in which the various schools of art struggle for the object of their lives, which is the beautiful.
I have said that art is realistic in its periods or moments of study; and this is essentially the case even with the school which in many respects was the most unmistakably decorative and idealistic in intention: the school of Giotto. The Giottesques are more than decorative artists, they are decorators in the most literal sense. Painting with them is merely one of the several arts and crafts enslaved by mediæval architecture and subservient to architectural effects. Their art is the only one which is really and successfully architecturally decorative; and to appreciate this we must contrast their fresco-work with that of the fifteenth century and all subsequent times. Masaccio, Ghirlandajo, Signorelli, turn the wall into a mere badly made frame; a gigantic piece of cardboard would do as well, and better; the colours melt into one another, the figures detach themselves at various degrees of relief; those upon the ceiling and pendentives are frequently upside down; yet these figures, which are so difficult to see, are worth seeing only in themselves, and not in relation to their position. The masonry is no longer covered, but carved, rendered uneven with the cavities and protrusions of perspective. In Mantegna's frescoes the wall becomes a slanting theatre scene, cunningly perspectived like Palladio's Teatro Olimpico; with Correggio, wall, masonry, everything, is dissolved, the side or cupola of a church becomes a rent in the clouds, streaming with light.