“I just happen to be an artist who uses the iPad, I’m not an iPad artist. It’s just a medium. But I am aware of the revolutionary aspects of it, and its implications.” In this interview artist David Hockney explains what a medium such as the iPad means to him. David Hockney is at Tate Britain, London SW1P, from 9 February 2017. tate.org.uk/visit/tate-britain – Who wants to join me?