Can you used colored light rays to stain things? I'm just super curious.
No. Bright sunlight can cause a color change, but that is a bleaching action, making the colors lighter. It is modifying the dye in the material. But with good dyes, that does not happen.
Light does not stain a fabric. But, light can cause a chemical reaction causing bleaching of the fabric. Although a particular color light reflecting off a colored fabric does not change the color of the fabric, it can cause you to see a different color. Green light on white fabric looks green Red light on white fabric looks red. white light on red fabric looks red. Green light on white fabric looks green red light on green fabric looks black green light on red fabric looks black
