It is unprecedented for an artist to be exhibited simultaneously in three of London's leading galleries, each one exploring a different theme: landscape, portraiture and still life. But that is the accolade bestowed on the internationally renowned British artist Tacita Dean. The granddaughter of Basil Dean, who founded Ealing Studios, she is celebrated for her works on analogue film which include beguiling portraits of figures she admires, enigmatic stories and painterly meditations on light. Alan Yentob joins Tacita Dean in her studio in Berlin to discover how the city has infused her work, and visits her in LA where she is completing an hour-long film inspired by her older sister Antigone and the Greek myth which bears her name. Her work is poetic, elegiac, and thought-provoking. It is also the story of her crusade to preserve the medium which inspires her - film.