Curtain Lining Fabric
Curtain lining fabric has several purposes. The first, is of course, to provide protection from the sun. The sun can fade the fabrics, and will rot them eventually. Depending on the construction, the lining can help stabilize the curtains. Curtain lining also helps keep light out of a room. Black out lining is used to really keep a room dark. It also will provide a bit of insulation as well. So, unless you want a sheer fabric, protect your investment in time and money, and line your curtains!