Optical brightener

Optical brightener Bright optical brighteners are fluorescent whitening agents, designed to brighten colours or mask yellowing in plastics, lacquers, paints, inks, photo-processing solutions and fibres. They function by absorbing invisible ultraviolet radiation and re-emitting it as visible light in the blue range of the spectrum. Optical brighteners are particularly effective in masking the yellowish cast sometimes observed in plastics and fibres after high temperature processing operation. They are also used in substrates containing pigments or dyes to make the colours appear more brilliant.