The History of Window Tinting

A Brief History of Window Tinting

Before World War II

The slick-shaded glass seen on today’s cars is the culmination of developments from medieval glass tinting four to five millenniums ago to the UV-heat-blocking film protecting vehicles today. The earliest known tinted glass items were found in ancient Egypt and Mesopotamia where early processes were used to tint and color glass for beads and decorative pots. Clear glass for windows was  developed in the following centuries. By the first or second century of the Current Era, the use of clear-glass windows was spreading throughout the Roman Empire. Coloring clear glass by adding metallic oxide powders followed. During the late medieval period, it was widely used to stain glass windows for palaces, churches, and mosques throughout Europe and the Middle East.

Auto Window Tinting Beginnings, Post-World War II

As the use of automobiles increased in the post-war years, more and more people became aware that temperature and glare from the sun were magnified through their car’s glass windows. Correction was needed. Industry responded. In the USA, Ford and Chevrolet began offering their customers a limited number of car models with glare-reducing factory tinted windows. Factory tinted windows, commonly referred to as “Privacy Glass” or simply Factory Tint, used an electrical process called “deep dipping” to dye the inside of automotive glass with a dark pigment.

Although most models lacked Factory Tint, consumers could and often did apply tint to windows themselves. They sprayed an aerosol suspension, which on contacting windows formed a dark layer of color on them.

The result was usually unsatisfactory. The procedure’s common outcome was a dark and often uneven shading that had not only been difficult to install, but was also prone to streaking. Furthermore, it limited driving visibility dangerously, and It did not block heat.

Window Tint Film

Window Tint Film, an improved tinting option, appeared in the automobile industry in the mid-1960s. Its installation was more efficient and consistent than sprayed on dye. It was economical. It could be used and removed at any given time. Given its benefits, the automobile industry began to favor Window Tint Film, gradually abandoning its use of Factory Tint.

Window Tint Film is a layered product. It has a layer of dye between an adhesive layer and a protective top coating made of polyester. The adhesive side sticks to the glass while the top coat protects the window from accidental scratches.

The new Window Tint Film provided car occupants with optimum privacy while effectively blocking visible light. To an outside observer, windows with high-shading percentages were black, but the people inside the car could see through the windows. It was primarily this property that popularized Window Tint Film.

By the late 1970s limousines all over the U.S., for example, were utilizing Window Tint Film — most with dark tints, some with shading of 80% or more. These darker tints were great for privacy, but not so great for visibility and safety. Accidents occurred forcing state authorities to react. By the early 1980’s, most U.S. states had passed laws regulating the tint level allowed on car windows.

Despite its advantages, Window Tint Film had shortcomings. Its ability to block heat (infrared or IR waves) was very low to non-existent. In very hot temperatures, the Window Tint Film would at times fail; bubbles would appear. Excessive ultraviolet (UV) exposure would fade blackened dye to purple over time.

In summary, dyed Window Tint Film had strong points and a glaring weakness. Its most favorable aspects were:

• it was economical;
• it was readily available;
• it effectively blocked the sun’s visible rays;
• it could be removed and economically replaced with another film;
• it provided driver and passenger privacy without compromising their external vision.

Its glaring weakness was its negative responses to heat and UV exposure. Not only did it fail to block heat; some of the rudimentary dye-based films absorbed heat into the vehicle rather than reflecting it outward. Furthermore, the sun’s UV rays and heat (IR) waves would cause film to prematurely fail. Bubbles would form. The dye would fade.

Metalized Window Tint Film

In the 1990s, small metallic particles were introduced to window film. Embedded in the film, they provided additional benefits. As metals, they reflected visible light and heat better than most other elements. Paired with dyes, which absorbed heat, they reduced about 50% of a car cabin’s exposure to interior heat. They were inexpensive. They strengthened the window film for more efficient and safer use. Security window film — a standard film feature today — prevented glass from shattering if broken. Other properties:

• Metalized Window Tint Film retained the non-metalized tint film’s privacy advantages while displaying a distinctive appearance. From the outside, the film appeared shiny; it was reflective.
• The metallic bits in the film did not compromise the ability to see out of the window. Miniscule, they could not be observed with the naked eye.
• The bits’ metallic ability to reflect heat facilitated the cooling of the car’s interior. Automobiles’ gas-consuming AC’s did not have to work as hard.
• Metalized window film’s superior response to heat and high temperatures. Besides reducing an automobile’s interior heat by about 50%, it preserved its dyes; they did not bubble or fade with time.
• The film blocked glare and, by adding an extra treated layer, blocked some skin-and-fabric-damaging ultraviolet (UV) rays.

Intermingled with metallized Window Tint Film’s advantages was an outstanding drawback. The metallic particles interfered initially with radio and later with cell-phone, GPS, and other satellite signals. This trait threatened to limit the potential extent of wireless communications.

Carbon Window Tint Film

Embedding particles of carbon (and polymerized) bits rather than metalized bits in the window tint film was an alternative innovation. Metal free, carbon film did not interfere with the electromagnetic frequencies that are used for radio, GPS, and cell phone transmissions.

Dark and matte-finished, carbon window-tinting film provided a tasteful aesthetic and long-lasting option for windows. Unlike dyed window tint film, it does not fade with time.

The carbon content of the carbonized film blocks about 40% of the infrared (IR) light waves (the kind that transmit heat) that enter through the windows. Being about as effective as metalized window tint films in blocking heat, it helps effectively cool interior cabin space. As a consequence, the air conditioner will not need to work as hard to cool the interior cabin space during the summer. Conversely the same heat-blocking (emissive) qualities of the tint also means that the car’s heating system will not be as heavily impacted during the winter.

Additionally, the carbonized film effectively reduces glare and the entry of damaging UV rays.

Carbon window tint film tends to be more expensive than metalized and other dye-based window tint films, but it is cheaper than ceramic window tint films.

Ceramic Window Tint Film

Ceramic window tint film is the newest edition to the window-tinting industry. It is the highest quality of window tint film available today. However, it is also the most expensive.

Instead of dye, metal or carbon, the film contains ceramic particles — essentially clay hardened by heat — which are nonconductive and nonmetallic; they do not interfere with radio, GPS, cell phone, or related wireless signals.

Ceramic films consummately reduce solar heat (IR) rays and damaging UV rays that enter the car. While they ably reflect and absorb much higher levels of solar energy than earlier tints, they also maximize visibility, providing superb optical clarity. They effectively resist glare. Moreover, they do not fade, and they are highly shatter-proof.

Ceramic window tint film is the crème de la crème of contemporary window tint films. While it provides many superior benefits, it has one notable drawbacks: its cost.