I always carry my film with me, and ask for a hand inspection. Often I am told that the x-rays are safe for up to 800 speed film. I have a roll of 800 and 1600 film I have been carrying for years just to help convince security to hand check my film. I carry my film in lead lined bags. If I do have to put the film through the x-ray, this helps protect it. It also helps protect the film during the flight itself. A family member once allowed one of my suitcases to go through one of the larger checked baggage x-ray machines. It completely ruined every single roll of film.