How many black light for a party needed? It really depends on which light are you going to rent. UV-18 is good to light up 20 x 20 room with 12' high ceiling. This is our basic light. It has a DMX channel so it can be synced to the music. But keep in mind, if any subject comes in front of it, the other subject behind him will not glow. So placing one light on each side of the wall (if on the floor) is a good idea.
How to set up a black light? Connect to the power outlet via included D-plug cable and turn ON the switch. It will glow anything in front of it.
What will glow under black light? Almost anything as long as it is white or fluorescent: any white subject, teeth whitener, postal stamps, body painting, counterfeit money, some jewelry etc.
How many black lights do I need? There is no set rule for that. In general, powerful lights are more effective and one light like (UV canon 400) is good for a party of 50 people
Does black light has any color? They don't have any color but they will glow anything white or fluorescence in the dark. They are called "black lights" because of their special effects.