There are many types of window tint available in the market for a wide variety of uses from solar heat reduction to UV protection, privacy to safety and security, decorative applications to heat retention.
Heat rejection films are normally applied to the interior of flat glass windows to reduce the amount of infrared

Infrared

Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...

, visible light

Visible spectrum

The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light. A typical human eye will respond to wavelengths from about 390 to 750 nm. In terms of...

, and ultraviolet

Ultraviolet

Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...

 (UV) radiation

Radiation

In physics, radiation is a process in which energetic particles or energetic waves travel through a medium or space. There are two distinct types of radiation; ionizing and non-ionizing...

 entering windows. Such films are either dyed or metalized (which can be transparent to visible light) to convert incoming solar radiation to infrared radiation, which is then rejected back through the glass to the exterior.