The impermanence of works of art is a worry for curators though not usually for artists, especially not at the start of their careers. But Anthony McCall was only in his mid-thirties when his creations vanished before his eyes.

It was in New York in the early 1970s that McCall came up with the idea of ‘solid light works’, animated projections of simple abstract shapes in which the beams of projected light assumed a physical presence.