Modern Xray film is used in "cassettes" that have blue, and or green phosphor screens which expose the film with visible light emitted from the screens in contact with the film. The X-rays cause the screens to glow, exposing the film.
Originally Posted by gatewaycityca
So X-ray film has to be sensitive to visible light. Only thing is the Xray film is only sensitive to blue or blue-green (ortho). This can be used as a creative tool in pictorial photography. As the X-ray film sensitivity gives similar pictorial results to the old Wet-plate collodion (tin type) photos, or in the case of the green sensitive (ortho), similar results to Ortho style camera film.