Anyone who has sat down to write a proposal for a documentary will know how impossible it can be to imagine the finished work. A documentary often starts as a hunch, a gut-feeling that you are onto a good story, is nursed through the preliminary research period into a treatment, but only begins to take shape once you are well into the thick of it and even then is constantly changing.
At least, that's the sense you would have got listening to a panel of three documentary makers at The Vancouver International Film Festival Trade Forum in October, as they described how they set about fashioning 90 minute films from "reality".
Ron Mann, who previously made marijuana doc Grass, said he got the idea for Go Further from the place where he gets all his good ideas - High Times magazine.
He read a short item saying that actor and eco-activist Woody Harrelson was doing a talking tour of the West Coast by bicycle with a follow-up gang in a hemp oil-fuelled bus. Mann having recently embraced the vegetarian "health and wellness" lifestyle himself, instantly thought this was a great opportunity for a natural-living "propaganda" doc. Woody was happy to oblige, and then it was a matter of saddling up with two Sony PD150 DV cameras and going along for the ride.
Fairly soon after the trip began it became clear that the film would be less focussed on Woody and more about a member of the travelcade who had joined at the last minute, "junk-food addict" Steve Clarke. Mann decided to focus on the transformation of this amusing Everyman, with his predilection for cigarettes, hotdogs and milk, to add a light touch to the film's serious political message.
"You start making one film and end up going down a side track," says Mann. Woody being the easy-going guy he is, didn't mind, says Mann. "The decision... was an organic process."
The organic way also has its pitfalls. Namely way too much footage - around 400 hours in total. "I didn't watch it all," says Mann, who completed the project from start to finish in one-and-a-half years.
Oscar-winning documentary maker Malcolm Clarke says he came out of retirement to make Prisoner of Paradise. The documentary, which earned him another Oscar nomination, tells the story of larger-than-life Jewish film director, Kurt Gerron who, as a concentration camp prisoner, made a nazi propaganda film about how wonderful it was in the camp in return for his life.
Clarke believed the simplest way to weave a way through the life of this "highly ambiguous character", from his heyday as a comic actor and well-known director in Weimar Germay to his time in Theresienstadt, a concentration camp for eminent jews, was through a standard chronology of events.
In spite of his experience, the project quickly took on a life of its own. "I had cavalierly considered 11 weeks," says Clarke, but making it was "a two year nightmare" with new people surfacing and thousands of hours of footage from archives flowing in.
"Just when we thought we were finished, something else would come in from Eastern Europe," says Clarke. The final product was "completely different" from the original documentary he set out to make.
For academic turned director Bill Siegel, The Weather Underground, which profiles the eponymous American terrorist group of the late Sixties and early Seventies, started as an "adolescent hot flush". But it took five years to make. Siegel worked on the film at weekends, while partner Sam Green nurtured it full-time.
"Once we delved, the consciousness and seriousness of it emerged," says Siegel. The film describes how a collection of ostensibly privileged, white students developed a violent political ethos that evolved into a campaign of bombing emblematic state institutions.
One of the biggest problems the filmmakers faced was getting archive material. After all, these were people who were outlaws. They disappeared and did not even contact friends or family.
"We had this vacuum of footage... it just crapped out," says Siegel.
It's a testament to the team's resourcefulness that the film is so compelling, combining archive news footage and contemporary interviews with those Weather Underground members who were prepared to talk on camera. The decision to avoid a Golden Oldies backing track for a jarring, trippy soundscape pays off too.
The film was like a juggling act with the filmmakers trying to speak to two audiences - those who knew of the Weather Underground and those who didn't. As well as the discovery of new footage or new people, outside events changed the tone of the project - in particular September 11.
"There were these 'oh cool' attitudes to the Weather Underground that go tempered," he says.
"It was constantly a process of making choices all the way to the end."
Making It is published on iofilm every Tuesday.