I'm looking for a film that can hold up to 4 hour night exposures. Basically, there is an activity with people and lights that I want to photograph that will take between 3-4 hours. I want to be able to capture the people's movement like you would star trails. There will be no artificial light other than lanterns held by the people moving. Moonlight will hopefully fill in the landscape.

Has anyone successfully done night exposures on that scale? (3-4 hours)
What film did you use? I was thinking of doing some tests with Provia 100 as a starting point. I want to shoot the final shot on 4x5 film. I'm thinking slide film of some sort.

-K