Understanding Window Tint Visible Light Transmission

Whether for a vehicle, home or commercial application when referring to window tint film, one of the most important characteristics is how much light the tint allows to pass through. In most applications, this is important when attempting to gauge how much security, privacy and protection from heat and harmful UV rays a tint offers. In automotive applications, however it is especially critical as a number of states have laws limiting how dark the tint can be on a vehicle’s windows. As a result, manufacturers of window tinting have created a method for calculating how much light a tint allows it to pass. However, there are a few things to consider when discussing the darkness of a window tint.

Checkout Tint World  for more info.Regardless of the application, all window tint film is measured by the materials visible light transmission levels (VLT). Simply put, the VLT value is the percentage of visible light the tint allows through from the exterior of a vehicle, building or home to the interior. The lower the VLT percentage, the darker the tint is and the more outside light it blocks. A tint that has a VLT value of 5 percent indicates that the window film only permits 5 percent of the exterior light to pass through it, while a film with a 50 percent VLT value allows 50 percent of the light from outside to pass through. Furthermore, as tints are also offered in a variety of colors as professionals respond to a tint they typically define it by the hue and VLT value of the tint. A charcoal colored tint with a 5% VLT is classified as charcoal 5%, for example. Likewise, a 50 percent VLT green colored tint film is called green 50 percent.

While many may assume that the only factor to consider when calculating the final VLT of the installed window tint is the VLT of a tint, there is one additional aspect that needs to be considered. Every piece of glass, regardless of the application, blocks a certain amount of light. As a result, glass also has its own VLT value which has to be taken into account to determine the final VLT value of the installed tint. For example, if a state law indicated that the lowest legal VLT value for a tinted car window was 30 per cent and an individual installed a tint with a 30 per cent VLT rating, the final VLT rating for windows would actually fall below the legal limit due to the natural VLT value of the window. For this reason window tinting professionals use a simple formula to calculate the final VLT value of the installed window tint:

V1 (VLT glass value) x V2 (VLT tint value) = V3 (End VLT value)

For example , let’s assume that the legal limit for a vehicle’s window tint is 30% and that the vehicle glass has a VLT value of 75%. In this scenario, since we already know the window’s VLT value and the final VLT value that we want to achieve, we just need to rearrange the formula to calculate the right tint to add as follows:

V3 (final VLT value) Ø V1 (VLT of glass) = V2(VLT of tint value)

0.30 (30 percent) unter 0.75 (75 percent) = .40 (40 percent)

According to this formula, installing a window tint with a VLT value of 40 percent will result in a final VLT value of 30 percent as desired. Professional installers using this formula save their customers a significant amount of money not only in traffic tickets for illegally tinted windows but also in reinstalling the window tint that most traffic courts require when a driver receives a ticket for illegally tinted windows.