Sheer curtains and window treatments. Sheer curtains are one of those timeless window treatments that will always be in style. The light weight qualities of sheer fabric curtains allow sunlight to shine through the fabric an illuminate a room. Popular sheer fabric curtain colors such as white, eggshell or natural coordinate easily with many other curtain designs such as valances or drapes to offer another layer as a design element. Sheer window treatments made with this polyester voile fabric are available in both ruffled and tailored styles. Window Toppers offers some great ideas for decorating with sheer valances. panels, door panels and ruffled sheer curtains.