This right here is the electromagnetic spectrum, a chart that shows us the different wavelengths of photonic radiation out there. Now, right in between ultraviolet and infrared radiation rests the visible light spectrum, a literal rainbow of frequencies that our human eyes can see (380nm through 750nm). When light hits an object, the different wavelengths essentially do one of three things, depending on the structure of the chemicals making up that object:
1. They get sucked up by the chemicals – that’s absorption
2. They bounce off the chemicals – that’s reflection
3. Or they pass on through – that’s transmission
The reflected colors are what have a chance to make it to your eye, so they make up the object’s color. Fluorescence is a trippy happening related to absorption, that can give you access to colors normally outside the visible spectrum. When you see something fluoresce, you’re kinda seeing a secret world beyond normal vision.