Painting over wallpaper leaves a noticable wallpaper texture. This article shows you a high-end alternative using the marble-like finish of Venetian Plaster to not only change the texture, but the color and finish at the same time.
Venetian plaster creates a luxurious polished marble-like finish over interior walls and ceilings. The manufacturer's instructions only apply to smooth surfaces. This article tells you how to apply it on an orange peel textured wall.