Optical brighteners, also known as fluorescent whitening agents, are chemical compounds used to enhance the appearance of fabrics and paper. They work by absorbing ultraviolet light and re-emitting it as visible blue light, making materials appear brighter and whiter. This effect is particularly useful in laundry detergents and paper products, where a clean, bright look is desired. These brighteners are commonly found in household products, such as laundry detergents and fabric softeners, as well as in commercial applications like printing and packaging. While they improve aesthetics, they do not actually clean or whiten materials; instead, they create an illusion of brightness by altering the way light interacts with the surface.