UV filters

The best UV filter is the Baader U filter. It is designed primarily for astronomical work, for looking at the clouds around Venus. You can shoot in daylight, but the results are highly variable, and the best light source is an electronic flash. You will need to remove the plastic Uv-absorbing window in front of the flash tube, to produce a ‘full spectrum flash’. I have several old Metz hammerheadstyle flash guns, where the window can be removed very easily.