In this brief excerpt from Primaries & Secondaries, a video made to accompany the 2007 exhibition of the same name, Robert Irwin talks about the development of his work in the late '60s and early '70s. The artworks shown in the film, including a dot painting, an acrylic disc, and an acrylic column, are on display at the Museum of Contemporary Art San Diego in the exhibition Phenomenal, California Light, Space, Surface until January 22, 2012.