Brett Morgen, the director of documentary Cobain: Montage of Heck, possesses two advantages few documentarians have. The first is that his subject – Nirvana lead singer Kurt Cobain – has become such a cultural icon that there’s no need for him to rehash the broad details of his life story. The second is his unprecedented access – through producer Frances Cobain, Kurt’s daughter – to heretofore unseen journal entries, home video and personal recordings.

These advantages aren’t wasted. Rather than affixing these materials to a digestible narrative or trying to ‘diagnose’ its subject, Montage of Heck weaves his life through an affecting melange of animation, stock footage and a select number of talking heads. Only the key figures in Cobain’s life – his family and close friends – appear, with only one notable omission (whose name rhymes with ‘cave troll’).

The carefully-curated materials (scored, naturally, by a range of Nirvana recordings) lend an intimacy and authenticity to the film; it operates as an experience rather than an explanation. It’s only occasionally that it feels conventional, as Cobain’s life assumes recognisable shapes and familiar stories – the melding of man and rock star mythos, the junkie tragedy – but it remains honest and non-judgmental throughout. A genuinely artful portrait.