What Element Is Used in Laundry Detergents & Glows in UV Light?

Optical Brighteners

• Optical brighteners are included in various liquid laundry detergents. These substances are made of tiny particles. When invisible ultraviolet light hits these particles, it is absorbed. The particles then reflect the light as a blue light. This is useful for laundry because the blue light reflected counteracts the yellow or orange light emitted by laundry when fabrics begin to fade yellow. This is why the substance is called an optical brightener; it does not actually brighten fabrics but simply makes them appear brighter when used.

Bluing Agents

• Laundry bluing agents have been used for decades by those wishing to create cleaner- and brighter-looking laundry. Like optical brighteners, which use particles to reflect invisible light spectrums, laundry bluing is yet another optical illusion. Laundry bluing adds just a trace of blue dye into the wash. The blue dye counteracts the yellowing that occurs over time on white or cream- and ivory-colored fabrics.

Ultraviolet Lights

• The short wavelengths of ultraviolet light make it invisible to the human eye. Ultraviolet light is divided into three groups by scientists: near ultraviolet light, extreme ultraviolet light and far ultraviolet light. Black light is a form of ultraviolet light that illuminates phosphorescent substances as the phosphors oxidize under the radiation of the light. Black light is the type of ultraviolet light most noted for making liquid laundry detergents, or items washed in those detergents, glow.

The Light and Laundry Connection

• Only liquid laundry detergents containing optical brighteners or bluing agents create a glowing effect under ultraviolet light. Bluing agents are actually made entirely of phosphors that make black light emit a glow. The substances deposit onto fabrics in the wash or onto any surface they come into contact with outside of the wash. Once the ultraviolet light meets these deposited substances, a glow is emitted that otherwise would not have occurred regardless of the color of the fabric.