Questions about the black light test

[golden spoon]

Swim has heard that the black light test is easy to do and works relatively well so decided to give it a shot. However, swim would hate to make any wrong assumptions. So just a couple questions.. What is the best color for the background surface? and How does ice look under the black light? In other words, how does one differentiate the good and the bad? Swim would also greatly appreciate any other info and whatnot.