My recollection is that X-ray film contains chemicals which will fluoresce when irradiated with x-rays.
Not exactly. The film is either just blue sensitive or orthochromatic. When used it is sandwiched in a cassette (flat film holder that opens like a book) between two phosphor coated plastic sheets, called screens, that fluoresce when struck by x-rays. In many ways it is a fairly conventional film although the spectral response is tuned to the spectral emission of the screens for maximum sensitivity. It is also coated on both sides, no anti halation and often on a blue colored base. Whether the dye trick would work or not I do not know but there is nothing really different about the film. Large format photographers use it sometimes because it is cheaper as it is still made in considerable quantity - compared to sheet films.