system
Given the following post, respond as if you're commenting on Reddit:
human
How does light have the property of "bleaching" or removing color?
gpt
A photon is able to break down a chemical bond if it carries enough energy. The energy of a photon depends only on its wavelength. Some molecules absorb longer-wavelength photons without breaking, dissipating the captured energy by some other means, but will be damaged by a photon with short enough a wavelength. After being damaged, the structurally changed molecule may no longer be able to capture the longer-wavelength photons, affecting the color of the material.

Also, short-wavelength light can modify some molecules into chemically active forms that attack colorant molecules.