How Window Film Works

Film Adheres to Windows

When the owner of a window, whether in a vehicle or a home, applies window film, he must use care to securely adhere the film to the window. Professional window film installers typically start with a high-quality polyester film and a very clean window. The installer then applies clear adhesive paste to both the window and the film, and applies the film to the window using a firm, solid pressure. He uses a squeegee to remove air bubbles from the film, and allows the paste to dry. With the paste dried in place, the film becomes permanently adhered to the window and ready for use.

Film Filters the Sun

When a window owner applies film, he generally does so with the intention of preventing the harmful effects of excessive solar radiation. According to Johnson Window Films, a division of Johnson Laminating and Coating, solar radiation consists of three primary portions: visible light, infrared rays and ultraviolet (UV) radiation.

Depending on the design and thickness of the window tint, polymers inside the film help filter some or most of the infrared and ultraviolet rays; the removal of these rays helps protect items inside the car or home from premature aging, fading, cracking and other damage commonly associated with sunlight. In addition, the dark tint of polyester window film helps capture some of the visible light entering a home or vehicle, creating a somewhat darker interior.

Some Film Reflects Energy

While typical polyester film absorbs some or even most incoming solar radiation, some manufacturers offer a special film designed to reflect rather than filter the rays. In reflective film, sometimes known as mirror tint, manufacturers insert small, thin and nearly transparent metal components into the polyester window film. As visible light, UV and infrared radiation hits the reflective window film, the metal components reflect the rays and provide further protection from radiation damage.

In addition, some window owners prefer reflective films for their increased privacy from outside individuals who attempt to look inside a home or vehicle; since the tint reflects light, these individuals may be unable to see past the film.

Window Film Reduces Glare

For drivers, window film's ability to reduce glare may mean the difference between a safe driving experience and a sunlight-induced crash. According to Johnson Window Films, window film absorbs or reflects a considerable portion of incoming visible light, helping drivers more clearly see the road and surrounding areas.

Reflective window films with metal components both reflect and absorb light, creating an ideal driving experience with only minimal glare, though dyed polyester film also helps improve a driver's visibility.