OK, admit it. You, like everyone else, loves seeing things glow under black light. Little kids eyes (and adults, too) light up when they see their costumes and clothing begin to glow. It just always adds that extra Wow! factor wherever it's used. And, it can do the same to your Halloween yard haunt or cemetery, too.
When purchasing black lights, shoot for the black light fluorescent tubes, compact fluorescents, or spot lights. The black light (incandescent) party bulbs don't really do much and end up being a waste of money.
Black light fluorescent tubes come in a variety of sizes from 18 in. to 48 in. They are even available in 6 in. battery operated models. You can get them just about anywhere from Labor Day through Halloween. And, there are plenty of places to get them on line, too. Also, many home improvement stores sell them all year long.
Place black lights in strategic places to maximize the effect. If you're going to use them to make your trick-or-treaters costumes glow, place your black light in an area where they'll have to bunch up a bit. That way, you'll get a bigger bang for your buck. Your front porch or entry way are a great place to start.
If you are looking to light up a large area with black light, you might want to invest in a high-powered black light unit or black light cannon. These are just a couple examples, but there are plenty more out there on the market. They are relatively expensive, but may end being cheaper than buying multiple smaller units.