Bleaching in the Light

what in light makes fabric fade?
- brittany (age 12)
Shawnee, ks

Usually it’s the ultraviolet component of sunlight which is so nasty to some dyes in fabrics and colored paper. Sunlight even lightens some people’s hair color. The chemical bonds in the dyes are sometimes so weak that hitting a dye molecule with an ultraviolet photon will break the bonds. Bleach acts in the same way, but the bonds are broken by a harsh chemical environment instead of light. We sometimes say that sunlight bleaches fabrics and dyes.

Tom

(published on 10/22/2007)