Blackout cellular shades and blackout roller shades block the most light of popular window blinds. The thick, layered construction of cellular shades prevents light seepage. Blackout roller shades have a special backing that stops light. For total darkness, consider combining blackout cellular shades with blackout roller shades in a double layer system for maximum light blockage. Wood or faux wood blinds with cloth tapes also offer excellent light blocking when fully closed.