BERLIN.- Jo Baer was a key figure among the celebrated protagonists of Minimalist painting in New York in the 1960s and first half of the 70s. It was during that period when she executed her series of different-sized squares as well as vertical and horizontal rectangles in the hard-edge style, works she later expanded into multipartite arrangements as diptychs and triptychs. The most prominent feature of her paintings of that era is her composition of white or grey central areas encircled by a very thin band of colour which in turn is surrounded by a considerably thicker band of black. In these works it was important to not consider the black paint as a frame and the white as the centre. Both white and black were the frames for the colour black functioning to enclose it on one side and white on the other, white pushing colour far enough apart to work as it