Just when you get used to the smell they find a human body, or mention a leprosy epidemic, and the sound man passes out. But at least it's at sea level — after the hell of 23,000' for BLINDSIGHT I'm relieved to look across at the ocean at all times.

Across the bay you can see Christ The Redeemer reaching his arms out to the wealthy in Rio's south zone — Copacabana, Ipanema, Leblon. They say even Christ turns his back on the north of Rio, where we are.

Don't worry, we have kidnap insurance, the producers tell me — from their desks on Ipanema beach. But seriously, everyone is wonderful. O2 Filmes, and Vik Muniz, the fantastico Brazillian artist who got me into all this, and our crew — our sound man's dad wrote PIXOTE, one of my favorite movies, and especially our producer Angus Aynsley. It's the most enjoyable shoot, notwithstanding the garbage.

Vik describes Rio as St. Tropez surrounded by Mogadishu. The garbage is the only place in Rio where the social extremes get mixed in together. The posh rubbish from the south zone with the cheap trash from the favelas. Garbage is the negative of consumer culture, it's everything that nobody wants, and when it disappears from everyone's lives, rich or poor, it doesn't disappear at all, it appears here, like a conjuring trick gone wrong.

Garbage is a matter of opinion, say the catadores who work here, sifting through. Tread carefully, because you are treading on money. On a bad day they make twice minimum wage salvaging cans, bottles, plastics, paper. Then somebody finds R$30,000 cash — while somebody else finds two headless bodies. After Carnival they pick out the discarded costumes and wear them as they work. When the airline Varig did a dump everyone dressed up in the air steward outfits and served each other recycled drink bottles.

That's the most striking thing, the good humor, the sheer fun. These people are having a good time. When we film The Governor, a grinning old-timer with a boombox strapped to his belly — he calls out "I'm gonna be on TV." "Yeah, the animal channel," comes right back.

And they are honest. They don't touch each other's piles of pickings. Many catadores had limited career choices: prostitution, drug traffic, or garbage, and they chose garbage, where the only person you hurt is yourself. There is a lot of pride.

Zumbi is the resident intellectual. We hear about him before we see him — we hear that when he sees a book, he doesn't see just recycling paper. He has kept every book he's ever found on the landfill, and he has a lending library in his shack. He's handsome, like a young Sam Jackson, with a white towel tied around his head and a paperback bulging in his shorts.

Half of the catadores sleep in the garbage, risking being run over by trucks, and the other half sleep in the worst favela in town. Their garbage-clad open-sewer favela makes the other favelas look like the Amalfi coast, with their brightly-coloured two-story buildings with twinkling christmas lights piled up the hillside.

Evenings we return to the south zone. I sulk as I head to a delicious dinner in a bulletproof car, I'd rather be with the catadores than these billionaires moaning about the price of contemporary art. How competitive the current art market is, because there is just so much money, you have to interview and practically beg for the chance to buy insanely overpriced art works by totally unestablished artists.

These are the people who are going to buy the art work that Vik is making in the garbage in our charity auction at Phillips. And these are the people whose garbage will be part of the piece. We're going to trace all these comings-and-goings of things.

When we ask the catadores what they want to do with the money from the auction, they say they're not sure, their first thought is that they don't really need anything. They have everything they need. Richer people are much quicker to tell you what they need money for. I guess the catadores know exactly where most things that people spend money on wind up.