What is E value optical brightener?

E value optical brighteners are a class of fluorescent substances used to enhance the brightness and whiteness of materials, such as textiles, paper, and plastics. They work by absorbing ultraviolet light and re-emitting it as visible blue light, counteracting any yellowish tones in the material. These brighteners are commonly added to laundry detergents and fabric softeners to give clothes a brighter appearance. Their effectiveness can vary based on the type of fabric and washing conditions.