NOVELTY - Protecting a substrate from light-induced degradation, comprises: either (a) providing a substrate comprising an organic polymeric material, and (b) disposing onto the substrate of layers deposited by layer-by-layer self-assembly, or (a1) the step (a) as above per se, and (b1) disposing onto the substrate of alternating layers of a polyelectrolyte and inorganic oxide nanoparticles deposited by layer-by-layer self-assembly, where at least a portion of the layers comprise an organic light absorbing compound and/or an organic light stabilizing compound dispersed within a polyelectrolyte.    USE - The method is useful in the article for protecting the substrate from light-induced degradation, where: the substrate is woven or nonwoven fabric, an optical film, architectural film, greenhouse film, window film, protection film, fenestration product, solar light tube film, traffic signage film, commercial graphics film, a solar photovoltaic front-sheet film, or solar power concentrating mirror; the optical film is a multilayer film comprising an ultraviolet reflector, a blue-reflector, a visible reflector and/or an infrared reflector (all claimed); and the substrate useful in architectural applications, greenhouse applications, window films, paint protection films, solar power applications, lighting, fenestration products (used in a building such as windows, doors, skylights or curtain walls), solar light tube products, other daylighting systems for transporting sunlight to interior rooms, commercial graphics films (including films for billboards, building exteriors, signage, automobiles and mass transit vehicles), traffic signage, and protection films such as car wrap films.    ADVANTAGE - The method protects substrate from light-induced degradation with improved optical (e.g. formation of haze) and mechanical properties, long term durability, and reflectivity.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) an article comprising the substrate and layers deposited by layer-by-layer self-assembly disposed on the substrate; and    (2) a random copolymer comprising repeat units derived from a monomer comprising a (meth)acryl or vinyl ether group, and an ionic group and at least one organic light absorbing or light stabilizing compound comprising the (meth)acryl or vinyl group.    DESCRIPTION OF DRAWING(S) - The figure shows a cross sectional view of an article.    Article (500)    Layers deposited by layer-by-layer self-assembly (510)    Disposed on substrate. (550)