Charlie Kaufman never explains the mysteries in his imaginative films.

Not now, probably not ever.

Asked if he is comfortable about the ambiguity in his work, from his Oscar-winning script for Eternal Sunshine of the Spotless Mind to his directorial debut on the new Synecdoche, New York, Kaufman smiles shyly.

"I'm not comfortable," he offers. "I desire it!"

So it was amusing to see critics at the Cannes and Toronto filmfests -- where Synecdoche was presented with star Philip Seymour Hoffman on the red carpet -- trying to pin down the shy, New York filmmaker, who turns 50 on Nov. 19.

Some suggested Synecdoche owes much to Fellini's classic about filmmaking, 8-1/2 (1963). Or to Bob Fosse's autobiographical All That Jazz (1979), in which he explores the indulgent life of a dancer facing death.

In Kaufman's film, Hoffman plays a playwright-director who spends decades trying to finish an autobiographical play. Sounds familiar but Kaufman shrugs off conversation about his "influences" with the observation: "I haven't seen them!"

As for critics, and others who might have theories on what his new film means, Kaufman says: "I'm very curious." He is even curious about Hoffman's analysis.

The actor told Sun Media that his character, Caden Cotard, is a man who faces death without finishing anything in his life. "This is a guy who is letting his life get unwieldy and out of his hands and out of his control."

Kaufman is intrigued but still non-committal. He does think Hoffman owns the role as much as he does.

"Everything is in collaboration," Kaufman says of his process. "There is a script and you talk about the script and there are ideas and you talk about the ideas and you figure out what is practical. There are a lot of issues about practicality. You figure out what we can afford to do and what we can't afford to do."

According to Boxoffice Mojo, Synecdoche cost $20 million, although Kaufman is mum. "I'm not supposed to say the budget," he explains of pressure from his producers.

But he admits to limitations. "Budgetary restraints do a lot to rein you in. There is just the practicality of making a movie. It is just ever-present and it was in this because it was such a large thing we were trying to do for a very limited amount of money.

"I will tell you we had 45 days to shoot 245 scenes." Hoffman's aging makeup, which took up to five hours a day, made things even harder, Kaufman says. "So it was very complicated and that pretty much defines what you get to do to a large extent."

It turns out that Kaufman, despite his mysteries, is a practical guy, Hoffman says.

"People will tell me: 'He's so weird, he's so surreal in what he writes.' The more I got to know him, the more I realized what he is writing about is really matter of fact. He is a man who is just trying to tell the truth in an honest way."

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