Automotive window tinting film was first introduced in 1966. As you might expect, it has been improved and is now made in several different materials of which ceramic is only one, and has been repurposed to some extent from making you look cool to actually being cool. Light and heat enter your car from three different segments of the radiation spectrum: infrared, visual and ultraviolet. Films that block infrared and visual light keep the interior of your car cool on sunny days. Blocking some of the visual light provides privacy, while blocking UV light protects your skin from the adverse effects of solar exposure.

Materials

Ceramic window film is made from nonmetallic nano-particles so fine you cannot see them with your naked eye and are even hard to distinguish under a light microscope. One high-end crystalline film is made up of 200 layers of optical material that is thinner than a sheet of copy paper. Then there are dyed polyester films, metallic films and two-layer films combining dyed and metallic films. Each of these other films are different from ceramic film and each have a place in the market.

Blocking Percentages

The different film materials can be manufactured with different percentages of transmission in the three light spectrums. When it comes to visual light, the law in your state determines how dark your car's windows can be tinted. You can go online to the International Window Film Association to find out how dark you can go in your state. A reputable dealer or installer should be able to keep you out of trouble with the law by providing you the legal requirements of window tinting in your state (see Resources).

Light Transmission

You can purchase ceramic films that allow 30 percent -- or the minimum your state allows -- up to 50 percent of the outside light into your car. Crystalline films, which are nearly clear, allow up to 90 percent light transmission. The dyed polyester and polyester or metallic films allow from 5 to 55 percent of the light through your car's windows. Fully metallic films shut light transmission down to 10 to 40 percent providing glare relief.

Heat Blocking

What will keep you thermally cool while you ride around in the sun is the amount of infrared and heat blocking your car's window tinting provides. The polyester and composite films will block from 45 to 57 percent of the heat. The ceramic film stops 59 percent of the heat coming through your windows while blocking up to 80 percent of the infrared light. Metallic film will block about 72 percent of the outside heat. The top heat and infrared stopper is the crystalline film. It will reject 60 percent of the heat and a whopping 97 percent of the infrared light.

Sun Block

The ceramic film differs from the other films in that it stops about 99 percent of the ultraviolet part of the spectrum coming through your glass. This is a Sun Protection Factor, commonly known as SPF, of about 1000. It offers far more protection than you can get from sunscreen, not only good for you, but it helps your car's interior as it sits out in the sun.

Electronic Signals

If you use a cell phone or smartphone in your car or have a GPS system or satellite radio, you can avoid almost certain interference problems by not selecting metallic film and avoid possible problems by not using composite film. The other films do not interfere with the reception of electronic signals.

Durability

The higher quality films, such as the ceramic, crystalline, top-of-the line polyester and fully metallic film will probably come with a limited lifetime warranty -- lifetime meaning as long as you own your vehicle. You will be warranted against degradation of the solar properties, physical properties, loss of adhesion -- as indicated by bubbles or blisters -- and change in appearance, especially the fading to purple of dyed films or corrosion around the edges of metallic films. Lower-end films may provide only a three-year warranty. The ceramic film, lacking dyes or metal, claims to provide good service for many years.