My film always goes trough the filmsafe scanners and I’ve had no problems even in China where they have x-ray machines at the train stations (due to people transporting fireworks illegally causing an explosion on a train). I shoot 100ASA, 200 or maybe 400 at night possibly but generally 100 slide film on the whole and have never noticed any fogging. According to the Lonely Planet Travel Photography: A Guide to Taking Better Pictures , Kodak have done tests that show film below ASA 400 can take 16 passes safely. In general i buy my film at the airport in duty free as it’s cheaper and is maybe one less scanner to go through (what do they do with stuff for these shops?) The newer high power scanners look like hospital CAT scanners and have a hexagonal or round ring which the scanned items pass through, these are generally used to scan hold luggage and you might as well throw away the film if it’s been through one. the Kodak link below has some examples of x-ray fogging, so you know what to look for. some info: http://www.kodak.com/global/en/service/tib/tib5201.shtml http://www.fda.gov/cdrh/comp/cabinetxrayfaq.html http://www.garymills.com/xrays/xray.pdf http://www.kenrockwell.com/tech/airline.htm The higher the ASA rating the more grain you will get and the shorter exposures mean the colours will be not as good. For good travel pictures (views and panoramas) you need as small an aperture (big number) as possible to get good depth of field, if it’s too dark you can use a tripod, which can safely go in with your hold luggage. if your anywhere sunny you should use a slower film or a neutral density filter to cut the light down.
The problem is just going to get worse as the threat of terror increases and they bump up the strength of everything you have to pass through. My flatmate lost two mp3 players going through airport scanners. Does it make a difference if you put the film in the center of your bag surrounded by socks? :o)