Xavier Grau trained in Barcelona, where in 1976 he took part in the exhibition Por una crítica de la pintura (For a Critique of Painting), in which the Trama group presented its magazine with the support of Antoni Tàpies (1923-2012). He thus joined this multidisciplinary group, originally consisting of José Manuel Broto (1949), Gonzalo Tena (1950) and Javier Rubio, with links to the French movement.

Grau was influenced by American abstract art. His composition is seemingly spontaneous, in gesture and colour, though it is actually based on a carefully thought-out structure. He constructs the picture by adding strokes and planes of colour, creating a skin in which this process of superposition is evident.

Lupus is a luminous, transparent work. The red recalls that of Broto: fiery, applied in thick brushstrokes to the point of impastoing the surface. The circular gestures drawn in black refer us to a working practice he was to refine during the eighties, so-called critical automatism, which is confined to the process of working on the canvas itself, with no preparatory sketches or prior studies, so that corrections become strokes and therefore part of the work.