Blackout fabrics are most commonly found in hotel rooms as curtain linings or drapery fabrics, blocking much of the light that would otherwise enter through a window when the curtains are closed. For travelers, third shift workers, and parents of babies, blackout is an essential element in the bedroom. Besides window coverings, other uses for blackout fabrics include wallpaper, movie projector screens and planetarium domes. This bestselling blackout drapery muffles sound and helps reduce out-of-room noises at the window. Perfect for homes nurseries schools and workplaces this drapery lining insulates and helps keep rooms cooler in the summer and warmer in the winter. This 3-pass lining allows you to use the lining as a standalone drapery if desired because it features a layer of white foam black foam then a third and final layer of white foam to achieve 100% blackout with both sides of the lining remaining white in color. Blackout refers to an opaque fabric used to black out light. Blackout fabrics are most commonly found in hotel rooms as curtain linings or drapery fabrics, blocking much of the light that would otherwise enter through a window when the curtains are closed.