I'd be wary of Chinese Xray machines.

Years ago...1991 in fact, I went from Hong Kong to Guanzhou via the hover craft. Ended up about 30 minutes out of the city proper in what can only be described as "the boonies" (tons of duck farms and those odd little tractors that look like overgrown rototillers). The customs booth was one guy with an xray machine.

He sat in a booth and your luggage went between him and the xray emitter...

Which was OPPOSITE him....

He had the door open to his booth too....

I guess that is one way to control the population there....

*shudder*

All things being equal, see if you can't secret the film on you. Pockets are GREAT for things like this, and if it does set off any metal detectors, you can just show them the film. Should be fine.