it is helpful to use of a black light to show where you've painted Liquid Bright Gold (LB Gold).
You can usually find a black light at a pet store that sells supplies for reptiles.
The black light causes Halo Luster to become florescent. That is, causing the luster to glow. You can see exactly what you've done with the luster and make additions or corrections using the black light to show you the way. Also the black light could be used sometimes to check whether or not the grounding oil is nice and even while pouncing it with a silk pad. Almost anything with fat oil in it with glow a soft yellow-green. Also some of the mineral oxides we use for paint, will glow under black light after grinding the color.
It isn't very useful for normal painting, because it alters the colors significantly.
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