glazing article comprises a substrate bearing a substantially transparent coating comprising an optically functional layer and a thinner anti - iridescence layer undercoat mediate the optically functional layer and the substrate . the anti - iridescence layer eliminates or substantially reduces iridescence and , in addition , is readily designed to make the overall coating colorless or to provide a substantially uniform , muted color . the anti - iridescence layer comprises a high refractive index zone on the substrate , having a refractive index higher than that of the substrate . multiple gradient step zones are stacked on the high refractive index zone , including a low refractive index zone . a second gradient step zone having a refractive index higher than that of the first gradient step zone is positioned on the low refractive index zone , such that the low refractive index zone is directly sandwiched between the two higher refractive index zones . anti - iridescence is provided for a wide variety of optically functional layers without significant impairment of the optical performance thereof .