Hockney made prints, portraits of friends, and stage designs for the Royal Court Theatre, Glyndebourne, La Scala and the Metropolitan Opera in New York City. Born with synesthesia, he sees synesthetic colours in response to musical stimuli. This does not show up in his painting or photography artwork, but is a common underlying principle in his designs for stage sets for ballet and opera—where he bases background colours and lighting on the colours he sees while listening to the piece’s music.