Optical brighteners, also known as fluorescent whitening agents (FWAs) or optical brightening agents (OBAs), are chemical compounds used in various industries, primarily in textiles, paper, and detergents. These substances absorb ultraviolet (UV) light and re-emit it as visible blue light, making colors and whites appear brighter and more vivid. Optical brighteners are often added to laundry detergents to give the illusion of cleaner and whiter clothing by enhancing their visual brightness. They are also used in the paper industry to improve the brightness and whiteness of paper products. Optical brighteners' ability to improve the appearance of materials under certain lighting conditions makes them valuable in enhancing the visual quality of a wide range of consumer and industrial products.