White Roman Shade Fabric Privacy Liners can add extra installation to your window treatments. Extra insulation can save you money on heating and air conditioning bills. The addition of an extra layer of fabric behind your window shade will also help to block the light, but this liner is not made of black out fabric. It is a high quality 100% polyester fabric blend that lets a gentle bit of light filter into the room. The fabric liner will fold up along with the folds in the roman shade when you are ready to let the light into the room. If you need to shorten the length of the liner, it is recommended that you tape the edge to be cut and hem it with fabric glue. The tape will keep the fabric from fraying. However, please keep in mind that making any alterations to the privacy liner will void the product warranty.