Types of Car Window Tintsby Richard Rowe
Contrary to the popular conception that window tint comes in only one of two varieties (dark or shiny), there is a great deal of difference in manufacture, appearance and durability between the numerous types. There are indeed two main categories of tint: filter-type and reflective tint. The sub-categories of the filter-type are dyed tint and deposited film, and their main uses are to reduce or modify the amount or color of light entering the vehicle. Reflective tints are used to reflect solar radiation for a reduction in heat, and include sputtered and hybrid films. Each is specialized for a specific purpose, and each type carries its own share of virtues and shortcomings.
At one time, the window tint's sole function was to either look good or to block an external observer's view of the interior. The first usage of automotive window tint was on Chrysler limousines in 1952 and was of the dyed-film type that remained dominant all the way through the early 1990s. These second-generation tints manufactured in the 1990s utilized metallic deposits in the polycarbonate film to create a chrome-like finish, whose primary use was to block solar radiation. The newest window films use nanotechnology to deposit crystalline oxides in the film, specifically calibrated to block infra-red radiation, the primary source of heat transfer through automotive glass.
Dyed window films are applied on the inside of the window and come in a variety of colors. The most common are black and gray, followed by blue and red in a distant last. Second-generation polarized films are highly metallic and difficult to see through from the outside, though are quite transparent from the passenger compartment. In fact, true polarized films have only a slight gray tint. Hybrid tints resemble polarized metallics on the outside, but use dyed polycarbonate film to reduce the interior light level. Nano-Carbon window tints are subtle and may only be visible from an angle. Some films have a slightly chrome-reflective surface, while others are bronze colored or even iridescent.
Dyed film tints are the cheapest and are available in a wide variety of colors and come stock on many cars. Properly done, high-quality dyed window tints can last many years, perhaps as long as the paint itself if cared for. Second-gen metallic tints have thus far proven to be the longest lived, as they reflect much of the UV radiation and heat that damages dyed tints. For those in need of discretion, they are also much more difficult to see through from the outside, but remain legal in many states. Nano-Carbon tints are the form-follow-function, sensible shoes approach. They do darken the windows slightly, and so carry a certain element of style, but are primarily used to reduce interior heat.
Dyed tints have longevity problems, especially when left exposed to heat and sunlight for long periods of time. Metallic tints look great on many cars and last much longer than cheaper varieties, but only come in a few colors and may not be legal in some states. Nano-Carbons work well, but are expensive and their longevity is still an open issue.
The legality of window tint varies by state, but the classification of tint generally concerns transparency. If a film blocks 10 percent of incoming light, it is called 10 percent tint. States can vary wildly as far as legality goes, from New Mexico's 20 percent rule to Alaska's driving-in-the-dark 70 percent allowance. Full-window metallic tint is illegal in many states, so check for compliance before buying.