The secret behind how those washing detergents "brighten" clothes and why LEDs will deter that effect

Couldn't make a shorter subject title without saying less. :/

Finally, I've been enlightened (via Gizmodo) on how some washing detergents actually do brighten clothes. Used to think this was just advertising gimmick but there is some truth to it. Detergents contain fluorescent whitening agents (FWAs) that absorb ultraviolet light and then re-emit it as a bluish tone which make old, yellowish clothes look bright and radiant again.

But this trick will not work when these FWAs are exposed to LED light source because LED emit very little to no UV light. Gasp!

There is a solution, though, and these come in the form of non-standard tuned LEDs that emulate halogen bulbs by emitting certain violet rays. Guess detergent companies would need to cut deals with LED manufacturers, huh?

via Gizmodo.