British artist Damien Hirst is the world"s richest artist and the Tate"s big retrospective marks the height of his power. Hirst"s atelier has been turning out dot paintings since 1986, and by the artist"s own estimate there are around 1,400 in existence. Is this a factory or an art studio? Product or painting? When his stock falls, how will the art market respond?Hirst is not only the world"s richest artist, but a transformative...