His eyesight deteriorated in the 1970s. In October 1983 he stopped painting when he became blind as the result of a brain tumor. By dictation, he wrote three final books on art. In one of them, "Mémoire de la chambre jaune" (published posthumously in 1994), he attested to having "sought out the voice of painting wherever it sings loudest. No doubt, in complete abstraction one has the feeling of a great shock, if not an explosion, and in approaching the real, one feels health and truth restored. The whole import of the successive periods of my work was to combine the two."