Voile curtains are similar to net curtains, but come in a wider range of colours and designs. Net curtains are usually available only in white and off-white, and are made from synthetic fibres. Voile is made from natural fibres or a blend of natural and synthetic fibres.oile curtains can protect you and those you love from wandering eyes and act as a deterrent to burglars. These curtains make it difficult for passing pedestrians to see what is inside the house and who is at home. However, these curtains tend to become see-through at night if a light is on inside the room.