Oh. I thought that is a subset of having fun.
My film was some Kodak BW left over from my photo hobby days. ASA 400 speed 35mm stored in the refrigerator in a metal can. I got into the TC stuff around 1992 and have moved on from there.
The film was in lead envelopes (made for 5X7 cut film packets) with a window of several layers of black construction paper. Ordinary paper envelopes would fog and from the lines I was getting it looked like there was some corona down close to the film. The lead foil envelops was from some stuff I bought surplus to make fishing sinkers.
I wasn't really interested in trying to produce X-rays . . . it just surprised me when I saw the glass in a lamp fluoresce and wondered why that was.