That depends. A lot of older X-ray machines were designed on the more is MORE philosophy, definitely ruining most film. The fine print on so-called ‘film safe’

That depends. A lot of older X-ray machines were designed on the more is MORE philosophy, definitely ruining most film. The fine print on so-called ‘film safe’ machines typically state they won’t visibly affect film slower than ISO800, inclusive. (Plus, the damage is accumulated, so if you lug a lot of film through a lot of airports, you will get the occasional nasty surprise.) That being said, I’ve never had any problems having my film -when I travel with it- inspected manually.