Of Airports and X-rays
X-rays can fog photographic film — everyone knows that, but beyond that, there is a lot of disagreement on what to do with that information. How much exposure is "safe" and what is your best option to avoid exceeding that amount?
First off, a little background: light exposes film, and since x-rays are nothing more than high-energy light waves (more accurately, they both fall within the electromagnetic spectrum), it stands to reason that x-rays would expose film as well. But just as a dark room or extremely low levels of light will not show up on film, neither will extremely low levels of x-rays.
The equipment that is used to screen carry-on bags, even post-September 11, uses low enough intensity x-rays that most film should be safe, but checked baggage is subjected to much higher levels of x-rays. Rule number one then is to not put unprocessed film in your checked bags. This includes cameras that have film in them of course. High-speed and infrared film may require special care.
Within the US you have the right to request a hand-check of your film. Even still, you might not always get to avail yourself of that right. With the heightened security presence these days, authorities are understandably cautious about most everything, and insisting on having your film hand-checked could be just the thing to make you miss your flight. You can make it easier on yourself if you want to go this route though by taking all your film canisters out of their packages and putting them in a clear Ziploc bag. Keep in mind that you may still have to put your film though the carry-on x-ray machine. Those lead-lined film pouches, by the way, are probably best left at home. Nothing stands out more than a large dark object that they can't see through. More than likely they'll just turn up the intensity until they can see what's in it. This might also just raise enough of a flag to get you elected for further scrutiny.
Personally, I just let them x-ray my film as carry-on to avoid the hassles. My film has been alright so far. In any event, get there early and go with the flow — relax, and try to enjoy yourself.
So, what about outside the US? All bets are off. Most places probably are safe for carry-on film, but some may not be. Be sure to check things out before hand to avoid any nasty surprises.
Another option is just to buy your film once you get to your destination and mail it back to yourself before flying home.