Shadow demonstrates the presence of an object, but it is also a proof of the absence because it doesn’t contain any part of the substances. Because of the duality, shadow is considered as the bearer of multiple significations. Platon offers the negative character, ‘illusion’, to the shadow. Shadow is only an image of an image, a deformation of adeformation of a reality and far off the essence of a thing. ‘Skiagraphy’ by Butades’s daughter, quoted in Natural History by Pliny, is to record the trace of her lover, namely, a substitute for the absence with the presence. We look for the platonic illusion through Christian Boltanski, and the inversion of the allegory of the cave through Bruno Perramant. A characteristic of the modern thought on shadow is the separation of the self, and an encounter with the other. The shadow by Jung is related to the dark side of the self. Gregory Crewdson extends it to the unconscious aspect of a society. In the deconstructionism of Derrida, the origin of the ‘I/self’ tracks back to ‘encounter with the Other before I am.’ The painting as the shadow is a place of the play of presenceabsence, and here I always encounter the other. In this respect, in Three Portraits (1984) by Francis Bacon, the other(’s photography) causes ‘I’(my shadow) and these shadows transcend the border between ergon and parergon.