Oil on 60 canvases. See also http://nga.gov.au/hockney/ "The painting is a culminating statement about the depiction and experience of space. By using different views taken over a period of time, Hockney refers to Cubism, where a subject is depicted from multiple viewpoints; to Chinese scroll painting, where different time sequences and landscape elements come together to form an apparent whole; and to his own set designs for opera." (http://www.irequireart.com/artists/david_hockney/a_bigger_grand_canyon-558.html)