Optical brightening agents (OBAs), such as Tinopal® CBS-X serve the purpose of making fabrics appear whiter and brighter. It does this by absorbing light in the ultraviolet and violet region (usually 340-370 nm) of the electromagnetic spectrum and release light in the blue region (typically 420-470 nm) through fluorescence. Tinopal® CBS-X not only enhances the appearance of cellulosic and synthetic fibers by its whitening effect, but it also has excellent cold wash performance, improved stability and is highly soluble in water at low temperatures.