“They’re about expanding small experience,” the German artist Katharina Grosse says of her site-specific installations. “By making something small really large, you slow the information and time down, like slow motion.” Grosse often spray paints surfaces, coating them in different colors and textures to change the viewing experience. This time, she suspends spray-painted cloth from the ceiling of the museum’s central gallery. The effect is of a crazy rainbow splashing down to earth. Five recent paintings by Grosse are also on view. —E.C.