Here is a new and greatly improved version of the discussion on the use of UV excitation light and blue excitation light. Included are a number of photographs using identical lighting gear sans the wavelength of light. One can clearly see the difference in color saturation, and emission intensity of how blue light wins the race hands down.
We have also generated a paper on exactly what a dichroic filter is, how they are made, why they are important and why you should not buy a torch without one.
Go to the Science tab at the top of the menu bar and you will find these references.