Premiere of the never-before-seen documentary on how Pau Riba’s double record Dioptria was made and what it meant. It was released by Concèntric between 1969 and 1970 and is considered the first and best Catalan rock record in history. The film, directed by Nolasc Riba with a script by none other than Riba himself – was made by Pere Pons and produced by Grup Enderrock ten years ago, dovetailing with the show entitled ‘35 anys de celebratge a Pau Riba’ performed at Barcelona’s L’Auditori as part of the Festival Mas i Mas.