The formal and conceptual interchange between painting and sculptural form is central to the development of his mature work. This is made apparent in the depictions of consciousness in the earlier paintings: perceived phenomena take shape within the mind itself. With the work on the busts of Diego around 1953 the figures once again become more substantial. In the later portraits Giacometti was able to free the faces from the illusionistic space of the picture to lend them an astounding presence. The viewer confronts the model just as the painter does, and by casting his eyes across it and through the concomitant perceptual process awakens it into life in the same way that art itself does.