Making an objective assessment of a documentary on a musician one admires is a tricky business. Does it matter if the film – however well made – looks unlikely to appeal beyond those already converted?

That couched proviso noted, it's hard to find fault with Lynn-Maree Milburn and Richard Lowenstein's lengthy, rigorously researched film on the late Rowland S Howard. The skeletal Australian guitarist and songwriter, who died in 2009, is probably still best known as a founder member of the ear-shattering avant-garde
noise-terrorists The Birthday Party.

The film confirms that competition with Nick Cave, the band's lead singer, contributed to Howard leaving the Party in 1985, but – for all the magnificent discord of the music – the film is gratifyingly short on ill feeling. Cave, interviewed at length, admits to some mistakes and is complimentary about his friend throughout.

Such luminaries as Kevin Shields, Thurston Moore and Bobby Gillespie turn up to mourn a somewhat overlooked innovator.

Howard’s later work with bands such as These Immortal Souls and Crime & The City Solution receives its due in a film that manages to scare up unlikely nostalgia for a scene cloaked in darkness and drugs. Essential viewing for enthusiasts of post-punk existentialism. Agnostics are also encouraged to submerge a wary toe.