system
Given the following post, respond as if you're commenting on Reddit:
human
What makes a colour "neon"?

Is there a special ingredient in neon yellow or neon orange dyes or colours that makes them particularly glowing?
gpt
A so-called neon dye or paint is actually fluorescent, which means that it can absorb a short wavelength photon, such as UV or blue, and emit a longer wavelength photon, such as yellow or orange.  A normal yellow object can only reflect a small range of the spectrum of light contained in the light illuminating it.  But fluorescent yellow can additionally convert the energy in the blue part of the spectrum, as well as any UV, and concentrate that energy in the yellow range, making it brighter than a normal yellow object.

This is the same phenomenon as in a fluorescent lamp where the phospher coating on the inside of the glass absorbs ultraviolet created by the mercury arc inside and converts it to visible light that is emitted through the glass.