Among the works that the gallery Hauser & Wirth shows at Art Cologne 2012 are Phyllida Barlow’s Untitled: Slick (2010), a large sculpture made of plywood, castors, timber, and other “poor” materials, and a neon sculpture by Jason Rhoades. In this conversation with art expert Dr. Bettina Krogemann, Anna Helwing of Galerie Hauser & Wirth [...