the first hour-long tour through the nga 's current exhibition , ` james turrell : a retrospective ' , in a no-frills approach to art led by melbourne-based artist stuart ringholt .
the tour guide for the retrospective , which highlights the 70-year-old american artist 's 50 years of work , said the experience creates an ` educational state ' for viewing the art .
` while to some people this might be a joke , it 's not to me .