"I'm trying to make them all the same starting from the assumption that the harmonics are flat, which they never are, and I'm underpowering the spell enough that they don't just turn up in the exact intensity I have in mind the way they would if I were using them for illumination. So when the harmonics are light-friendly, they're bright and steady, and when they're not, the positions of the lights that are dim or wobbly or both and how much of each they are tells me what the harmonics are relative to the bright steady ones that best approximate the level of my 'flat' assumption."