Curtains and draperies are chameleons. They work hard at blocking light and sound, heat and cold. They’re also extraordinarily decorative and add enormous personality to a room.
What’s the difference between curtains and draperies — and does it even matter? Traditionally, windows were treated to three types of curtains: a sash curtain or voile (to filter light), a working curtain (to block out light), and an dummy curtain (which was purely decorative). In very formal rooms (with sufficiently high ceilings), all of this was topped with a cornice or valance (to hide the hardware). This traditional treatment carries on today in period or very formal or dressy rooms.
Another modern move is to drape and swag fabric loosely over a decorative end cap, in a nod to conventional valances and swags. Often, swags serve no function, but earn their keep by looking dramatic. We do this in bathrooms and dressing rooms.