re; X-Ray film
It's sensitive to visible light. XRay film holders have an "intensification screen" in them that fluoresces when bombarded with XRays, that fluorescence (visible light) is what exposes the film. The XRay films I've worked with are double coated with no anti-halation layer, so both sides expose at once.(a speed enhancer?) Back in the day, Freestyle sold "Aristo" Rare Earth Blue XRay film which was cheap and fast, it was very popular with pinhole photographers. (after Freestyle got out of the XRay film business, I ended up with a box of Fuji XRay film, slower, but finer grained) I experimented and got good results with D-76 and HC-110.
Good Luck, Have fun, Tracy