Visitors look at ‘Dirty – Jeff on Top’ (1991), by artist Jeff Koons, during a press preview of the exhibition Pop Life: Art in a Material World, at Tate Modern in London. PRESS ASSOCIATION Photo. Picture date: Tuesday September 29, 2009. The exhibition examines the ways in which artists have built up personae and brands for themselves since the 1980’s. Watch for PA story ARTS Pop. Photo credit should read: Yui Mok/PA Wire