Orange Sunshine is billed as a ‘little-known moment in American history,’ although of course it takes place in perhaps the most analysed and written-about decade in the history of the world.

Nonetheless even in the well-trodden ground which William Kirkley covers he manages to find some novel and interesting moments.

The film is the story of The Brotherhood of Eternal Love, a group of your friendly neighbourhood hippies who got super high in the early 1960s and decided to form a church and produce industrial quantities of acid.

They did this with the intent of distributing it for as close to free as possible, pursuing a goal of mass enlightenment through hallucinogens rather than monetary gain.

It’s an entertaining tale told mainly via the medium of modern talking-head interviews with some of the surviving members of the group. They’re an engaging bunch, all decked out in grey ponytails and tie-dyed shirts, and clearly relish the opportunity to recount their youthful escapades.

These interviews are interspersed with archival footage and dramatised scenes of some of the more pivotal moments, treated to look like they were shot on old 8mm home cameras. A little more of the archive footage would have been nice, since half the fun of these documentaries about the sixties is catching a glimpse back at a world which seems so removed from anything which came before or since. But losing a little of this immediate context for the sake of keeping the plot humming along is a fair exchange to make.

And there’s plenty of plot, too, which Kirkley has done well to tease out into a coherent narrative.

This could have easily been an infuriatingly meander through the smoke-wreathed memories of a few ageing beach bums, but you can feel a rigid discipline keeping the whole thing on track. God knows how many hours of rambling reminiscence is lying on the cutting room floor, but the film is kept taut and surprisingly lean in its presentation.

Almost too lean, on occasion. There are many ludicrously fascinating asides that one feels could have been a film in their own right. The Brotherhood would procure vast quantities of hash by flying to Germany and then driving to Afghanistan, for example, and the film spends far more time on the mechanics of rigging a VW van to smuggle the stuff back through Europe than it does talking about that actual experience.

What the film does spend a lot of time on is underlining the closeness of the Brotherhood. From the suburbs of Venice Beach to the Colorado mountains, this fundamentally remains a movie about a group of people united not so much by their desire to turn America on as much as their obvious love for one another.

Half a century later there are still tears as they recall the death of one of the founding members of the group. And the sadness – as time and the efforts of law enforcement gradually splinter the Brotherhood – is not so much for the death of the enterprise as it is for those halcyon days of friendship.

So Orange Sunshine is both a more and less entertaining movie than it could have been. Baby boomers looking for a nostalgic wallow will probably be disappointed, since the tight focus on the group cuts out much of the wider context.

Those seeking an in-depth look at America’s drug laws will probably also find it lacking; it’s clear that no one involved has even a smidgen of regret or moral ambivalence over what they did, so much so that they don’t even really bother trying to justify themselves or analyse the issue.

But for what it is – a tale of a friendship set in the context of a madcap jaunt through the trials and tribulations of mass narcotics production – Orange County is a well made documentary which never loses sight of its emotional core, and is all the stronger for it. 3/5

Keep up with the latest LFF2016 reviews in our London Film Festival section, including the powerful visual essay The Illinois Parables.