When David Hockney in the 1960s turned his attention to a photograph of a splash-splattered swimming pool, he did what most of us today, immersed in an endless stream of digital images, do not. He kept looking. For two weeks, the artist worked tirelessly from the photo to perfect his rendition in his acrylic painting A Bigger Splash , of the dancing droplets that erupted when some long-forgotten swimmer threw themselves into the deep end. The splash ended in an instant. Yet captured in Hockney’