I lost 75% of a 7 hr Wedding thanks to a lab screw-up. Never messed up film loading on my end. Just luck of the draw I guess.
It's hard to believe that this happened. I'm in photo printing business for over more than 20 years and I can remember only two cases of film being fogged by X-ray. The worst case was severe damage from scanning by unskilled custom guards with obsolete machines in some low developped country. The other case was very light fogging the customer did not see.
Well, I suppose it might have just been a bad roll of film, but I can't come up with any other explanation for what happened. You can see the graininess all over the negatives, too, so it wasn't just a bad print job - something clearly happened to the film itself. I know it was exposed to the x-ray, so that's what I've always believed was the culprit. Though, you could be right. It's possible, I suppose, that it was just a bad roll of film.
Its likely that the film was actually x-rayed twice.... once each way on a round-trip. Also, the film speed will make a difference. Higher speed films are more sensitive to x-rays. And finally..... perhaps it was an old roll of film that was already feeling its age, and/or had gone travelling (and been x-rayed) previously. Two trips = 4 times through the x-ray machine! I believe that the x-ray effects are cumulative.
I got into the habit of marking each roll of film that had been x-rayed (with an 'X' of course ) each time I travelled. I was suprised one day to find I was about to use a roll with 4 'X's on it. The marked rolls I saved for less important shooting, and only used clean rolls for important stuff.
A 'real' film camera will hold one sheet of film at a time!
By far my worst film gaff, though, was getting back from a vacation, getting my photos printed, and having them come back very grainy and orange. At first I thought the lab must have screwed up, and I was about to take them back and demand a reprint when I realized that I hadn't taken the unexposed film out of my bag at the airport on the way there...it had been x-rayed, and then I had put it in the camera and used it.
Get yourself a "real camera". One with a thumb lever film advance. You can feel the film moving through the works with your thumb on that kind of camera. I've never made that mistake on a manual camera. It's easy to make that mistake on a motor driven camera.
A "real camera" works even without the batteries installed.I suspect I'll still own my old F2 even after by DSLR has been upgraded twice.