Unfortunately, there is only a brief excerpt of Tony Conrad’s most significant film, The Flicker, online. It’s also a film that suffers significantly from being reduced to the screen of the laptop – you really do need to take part in the immersive experience of the cinema to fully understand The Flicker. By the time the film was completed, in 1966, Conrad had already been fundamental to the drone music explored in the Theatre Of Eternal Music, a music he’d return to with renewed vigour in the nineties, had been a key player in the formation and history of The Velvet Underground, and was central to New York’s underground film movement. He’d also done some time as a computer programmer. It’s tempting to see the latter as having some impact on the formal dimensons of The Flicker, a film of alternating black and white film stock. The quick flashes of light produced when the film was projected led to audience members hallucinating various visions while watching the film; some other audience members became ill, and due to the nature of the film, its strobing intensity can cause epileptic seizures. But its formal properties, and its mathematical insistence, made it perhaps the key film to the subsequent development of structural film across the seventies.

• Jon Dale