No film of manageable length could do justice to the sprawling, disordered career of Orson Welles. “There used to be a division of actors in the Comédie-Française in France – they were called King actors,” Welles once said. He was also a King director, King writer and King producer. Despite endless setbacks, Welles spread himself across the last century in a wave of unwieldy creativity.

Mark Cousins, the restless Northern Irish cineaste, has wisely structured his documentary around one under-explored aspect of Welles’s career: a collection of drawings and paintings that take us through the entire life. Cousins sees clues to the Welles aesthetic in the strokes. He uses them to explain the development of certain works. But he mostly uses them as a guide – walking us through the work as Welles’s hand walked his line across the page – from a childhood in Illinois to precocious exploration in Ireland to experiments in theatre to apotheosis in Citizen Kane and onwards to the wandering ups and downs of his troubled later decades.

If you’ve seen even a second of a Mark Cousins joint you’ll know to expect his lilting voice to make personal connection with his subject. “Dear Orson,” Mark intones as he contemplates a carton containing the artwork. “What’s in the box?” he asks over and over again in unmistakable Cousinian vowels. What indeed?

Cousins takes his camera back to Dublin and Galway. He muses on his hero’s work in the Gate and his travels out west while speaking as if in a trance of adoration and creative bewilderment.

The style is not to everyone’s taste. Some prefer the documentarian to sit a little further back when taking us through history. Those who do engage with Cousins’s long vowels will, however, find much to savour in his raptures.

As The Eyes of Orson Welles goes on, the film becomes less about the art and has more to do with Cousins’s own diagnosis of Welles. He believes in chivalry. He had an inordinate love of place. Yes, he was a “king” figure. No pat conclusion is reached, but Cousins does note that, unlike Olivier, Welles’s Shakespeare films were defined by space and shape. This is, he surmises, why fans of Larry’s contemporaneous pictures are rarely keen on Welles’s grander strokes and more idiosyncratic lines.

Cousins also concludes that Welles is still very much a contemporary figure. With the restored version of The Other Side of the Wind, one of several unfinished Welles works, making its way to the Venice Film Festival in a few weeks, that is now literally true. The Eyes of Orson Welles offers all the grounding you could desire.