Blog post: swansont: How Black Light Works

Bananas are extremely cool in black light, especially around their spots, which have deposits of phosphors. Banana spots glow in leopard-like patterns under black light. Chlorophyll glows red, and vaseline glows blue. Tonic water glows in black light. Vitamin A and the B vitamins thiamine, niacin, and riboflavin will all glow under black light, especially if they're soaked in vinegar. Simply grind up vitamin tablets, soak them in a little vinegar, and either leave them around or serve them as salad dressing.