Dear Andrew,
   Ultraviolet photography and B & W film do not necessarily go together. I
have taken some great ultraviolet photographs, but they have been in color.
You need color to see the various colors in the shells. Cypraea mappa with
the red base is so beautiful under U/V. Angaria vicdani is breathtaking and
even some fossil cones and junonias are super but only with color film.
  I use a 35mm manual camera, set it up under U/V and focus etc, set the
timer for 1 minute and expose the film. Comes out very well. I have also
positioned the shell on one side of the camera's viewfinder and taken one of
regular light and switched it to the other side to take u/v on the other half
of the picture.
           Good luck,
                 Carole Marshall