Re: What kind of paint best glow under black light ?

You are correct white paint is best.  Basically white is best because when 
it fluoresces it emits white light which is why whites appear "whiter that 
white"!  If however you don't want to use white paint and still want to get 
a good glow the next best thing is to use a DAYGLO product or similar 
products that are impregnated with pigament that glows when black light is 
used.  So you can have a blue paint that contains a fluorescent pigament 
that will do the job the white paint does.  Obviously the disadvantage of 
this is cost as white paint is very cheap where as a speacialist paint such 
as dayglo is always going to be more expensive.

As for the science bit, well here it comes:
For an object to glow under black light (also known as ultraviolet light or 
UV light)the object must fluoresce.  Fluorescence is defined as an atomic 
process in which an orbital electron is excited to a higher energy level by 
an external photon, spontaneously de-excites to a lower energy, and emits a 
characteristic low-energy photon. This process can continue, with 
low-energy photons emitted for each drop in electron energy,until the 
electron reaches the ground state.