Optical Brighteners: Are Your Clothes as Clean as They Appear?

For years, laundry detergent companies have been fighting to win the title of "brightest whites and colors." In order to make your fabrics appear cleaner and brighter, many popular companies use what are known as "optical brighteners" in their detergent formulas. But what exactly are optical brighteners? How do they work, and what environmental repercussions can stem from their use?

What are optical brighteners?

Optical brighteners, also called brightening agents, fluorescent bleaches, and optical whiteners, are chemicals designed to help fabrics appear to be cleaner, brightening colors and lessening the natural yellowing of fabric over time. Some examples of optical brighteners are coumarins, naphthotriazolylstilbenes, benzoxazolyl, benzimidazoyl, naphthylimide, and diaminostilbene disulfonates (about.com). These ingredients are often shown on the labels of laundry detergents, but often are omitted.

How do optical brighteners work?

You may recall your mother or grandmother using a product called "bluing" in her laundry to make whites appear brighter. Bluing agents remove yellow light to lessen the yellow tinge, but optical brighteners act differently. These agents "absorb ultraviolet light and emit it back as visible blue light. This blue light masks any yellowing that may be present in the treated material and makes it seem brighter and whiter than it would otherwise naturally appear to the eye" (seventhgeneration.com). Your clothes are no cleaner than they would be if you used a detergent without brightening agents, but they appear to be.

Optical brighteners are not effective unless they remain on the fabric after washing. Clothes washed in detergents containing these agents will have a chemical residue left behind on the fabric. This is why line-dried clothing often feels stiff unless fluffed in the dryer. Clothing laundered in detergent without optical whiteners will feel soft right off the line.

Can optical brighteners affect my family's health?