Watch " " Online HDToday. “Tree ferns filmed and then re-filmed on black and white film are inter-cut to produce a collage of green tinted positive images and green toned negative images. As the ferns’ leaves are pale in dark surroundings, the tinted positive yields green leaves in a black background, and the toned negative green leaves in a white background. Excerpts from Schubert’s Schoene Muellerin lament and laud the colour green by turns.”