ABSTRACT
Hugo van der Goes's Portinari Altarpiece, like most Netherlandish altarpieces of the fifteenth and sixteenth centuries, is equipped with a set of wings. To be sure, the exact circumstances surrounding the opening and closing of altarpieces still remain somewhat unclear. The process of opening the altarpiece does not appear to have been part of the Mass ritual, for altarpieces were never required elements for the Eucharistic ceremony, unlike crucifixes, censers, patents and chalices. Instead, the opening of the altarpiece most likely was part of an overall preparation of the altar prior to the celebration of the Mass. The exteriors of many Netherlandish altarpieces of the fifteenth and sixteenth centuries very frequently were painted in grisaille. But the role of grisaille on altarpiece exteriors takes on a different cast when conceived not as part of a binary opposition, but rather in relation to the exterior's placement in the spaces betwixt and between the viewer and the altarpiece interior.
