Laundry Detergent Whitening Trick Doesn’t Work with LED Lights

White Shirt

According to a recent article on, for years the detergent industry has added fluorescent whitening agents, or FWAs to laundry detergent. Why? FWAs absorb invisible ultraviolet light from incandescent and halogen light sources and re-emit it in the bluish white part of the visible spectrum. This bit of magic renders worn, yellowing shirts a brighter white to the human eye.

This trick has worked for decades. But with LED lighting showing up in more homes and businesses the trick is a dud. FWAs are useless because most LED light sources emit no ultraviolet light – one of the many benefits of LEDs for the consumer. But, for the bright-white obsessed laundry detergent industry, it means looking elsewhere for the white magic.

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Dave Burtner

Dave has been active in the lighting industry since 1994. Formerly a member of the Illuminating Engineering Society of North America and certified by the National Council On Qualifications for Lighting Professionals, Dave now writes blog posts, lighting tips and provides lighting product assistance for the Topbulb website.
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