A curtain (sometimes known as a drape, mainly in the United States) is a piece of cloth intended to block or obscure light, or drafts, or water in the case of a shower one. It is also the movable screen or drape in a theater that separates the stage from the auditorium or that serves as a backdrop.
Curtains hung over a doorway are known as portieres. Curtains are often hung on the inside of a building's windows to block the passage of light, for instance at night to aid sleeping, or to stop light from escaping outside the building (stopping people outside from being able to see inside, often for privacy reasons). In this application, they are also known as "draperies". They come in a variety of shapes, materials, sizes, colors and patterns, and they often have their own sections within department stores, while some shops are completely dedicated to selling them.
Curtains vary according to cleanability, ultraviolet light deterioration, oil and dust retention, noise absorption, fire resistance, and life span. They may be moved by hand, with cords, by press-button pads or remote-controlled computers. They are held out of the way of the window by means of tie-backs. Measuring sizes needed for each window varies greatly according to the type needed, window size, and type and weight of curtain.
Curtains are a form of window treatment, and complete the overall appearance of the house. Window treatment helps control the ambiance and flow of natural light into the room. The effect of drapery is best seen in daylight, and with proper indoor light positioning, can look attractive even at night.
Curtains are manufactured from a variety of thick fabrics, each with a differing degree of light absorption and heat insulating qualities. For maximum temperature control, the gap to the window should be small, with minimum convection drafts below or above. Various architectural structures around the it can minimize these air drafts, but usually they are just used for decoration and make rooms feel more cozy.
A sheer is one that is made from translucent fabric, such as a loosely woven polyester voile or a cotton lace. Sheer curtains allow a majority of light to be transmitted through the fabric, with the fabric weave providing a basic level of UV protection while retaining maximum visibility outward. Sheer curtains are sometimes referred to as "privacy curtains" in reference to their screening abilities; during the day most sheer fabrics will allow people inside the home to see the outside view while preventing people outside the home from seeing directly into the home. Due to the loose weave in sheer fabrics, these types offer very little in the way of heat insulation.
Uncoated fabrics provide the next level of heat insulation and light absorption. Uncoated fabrics constitute the vast majority of fabrics used, and are composed of a tightly woven fabric, most typically a cotton/polyester blend, which is mostly opaque when viewed in ambient light. Uncoated fabrics provide a reasonable level of heat insulation due to the tight weave of the fabric. However, the fabric itself is typically not thick enough to completely absorb strong light sources. As a result, when curtains made from uncoated fabrics are closed in an attempt to block out direct sunlight, light will still be visible.