For this reverential documentary portrait of the British artist Ralph Steadman, best known as Hunter S. Thompson’s illustrator, director Charlie Paul overloads the screen with visual flair. Paul’s frenetic assemblage strives in vain for the cinematic equivalent of Steadman’s splotchy urgency, but does at least make clear the big difference between vicious caricature, a Steadman specialty, and its own fawning hagiography. The film’s foundation is a perfunctorily inquisitive visit to Steadman’s country mansion from admiring pal Johnny Depp, who played Thompson in Fear and Loathing in Las Vegas and has been a sort of self-appointed Gonzo spokesperson ever since. With his credentials and friendly appreciation established, however, Depp’s presence becomes rather useless here. Too often it’s him we’re looking at: sipping coffee, lighting a smoke, muttering, “mm-hm, sure,” and generally digging Steadman’s work (a small bit of which we do see being made). While it’s good for an interviewer to keep his subject talking, it’s also good to keep the camera on the subject. Otherwise we’re prowling through the artist’s workspace, urged along by a strangely tone-deaf blare of soundtrack indie rock. “Authority is the mask of violence,” Steadman says at one point, usefully recalling a formative experience from his schoolboy years. As a survey of his lifelong effort to rip that mask off, For No Good Reason succeeds. As a survey of the life, not so much.