What was the color of the 1970s? Lynne Ramsay's Ratcatcher looks at the same period represented in such sunny fashion by Almost Famous, a concurrent release. But its setting is grim Glasgow council flats afflicted by a long-running dustmen's strike: a landscape of piled-high garbage, brackish canals, and the skittering rodents of the title. According to director of photography Alwin Kuchler, "We were hoping for a hot summer, so you would feel that emanation of rubbish and heat and smell. But it was the worst summer in the history of Scotland, which slightly played against us."

The cinematographer turned to tricks of the trade to create the requisite atmosphere. "We tried to find a filtration that reflected something of the 70s," he says. "We used things that would normally be used as lighting gels to give it a more brownish quality: Flame Green, mixed with an orangey gel ordinarily used for corrections. We also shot the film on Fuji stock, which gives you slightly more of a pastel range of tones."

Though Ramsay, making a feature directorial debut that was impressive enough to be included in 2000's New Directors/New Films Series at New York's Museum of Modern Art, was scrupulously realistic in representing her setting, she also wanted to catch something poetic in the plight of the troubled 12-year-old protagonist. The movie was shot on location, but the existing canal was too polluted, so a new one had to be built. Also, the interior of the boy's flat was constructed in a studio, to expedite filming.

"In real life, the flats are extremely small," says Kuchler, a German-born DP who met the director at the UK's National Film and Television School, and collaborated on several shorts with her. "The studio allowed us to slightly enlarge it, to be able to back off the camera a bit more and play the scenes on longer lenses. We used a lot of Arri variable primes, which enable you to slightly alter the frame as you, say, sneak in on the kid without having to move the camera. A lot of cinematographers are very snooty about zoom lenses, but they help you very much if you work in an environment where not every step is rehearsed."

At the same time, Kuchler carefully avoided too much artifice. "The danger of going into a studio is that you light it like you could never light on location, so we stayed away from things like that," he says. "I lit as much as I could through windows, sometimes just using a light bulb in the middle of the room to recreate the harshness. Lynne said to me and the production designer that she would kill us if it didn't look like a real flat.

"For the studio stuff, we used tungsten light, which had more to do with money than anything else," the DP continues. "I would prefer to light even the studio with daylight. On location, we sometimes used Kino Flos, sometimes HMIs." And always attended to the palette: "Instead of using white reflection, we painted the reflectors a sandy color, or a slightly greenish sandy color, just to alter the color of the shadow on a face. It was all about creating this world of the 70s."

Ratcatcher will be released this month by Merchant Ivory Productions.