What can seven big circular paintings by Olafur Eliasson, which look rather like giant designer-colored CDs, have to do with Britain's greatest and most visionary painter, William Turner? Eliasson's Turner Color Experiments are the support act for the blockbuster Turner show at Tate Britain in September. The connection between the 19th-century genius and the 47-year-old, one of the most feted artists of his generation, can be summed up in a single word: ephemeral.

Not ephemeral as in our pixellated, fibrillating world of next-up, whatevers, and microsecond stock-market differentials.