I frequently travel with a load of film, and never allow it to pass through x-ray equipment. But I do prepare carefully to help them be efficient, including packing it for easy inspection, and packing it for easy removal from my other carry on luggage to minimize the delay for other passengers behind me. If possible, pack all your film in one clear plastic bag at the top of your carry on, and pull it out before you get to the inspection point. When you get there hand it to them first thing and ask for a hand inspection, as you are preparing your other stuff to go through the machine.

I've never had a problem with this process, though they do sometimes ask you if you would put it through the x-ray machine. I always decline and again ask for hand inspection, and I've never had them resist when I insist.

Do watch them inspect though. One inspector in China almost opened my partially used box of 4x5 sheet film before I reached over and physically stopped her, politely saying "Bu, bu, bu, bu!" (No, no, no, no!). She nodded in understanding and stopped, thankfully.