You can tint over factory tint. Many trucks and SUVs are equipped with factory tinted glass on all windows behind the front doors. Factory tint, officially known as Privacy Glass, involves dying the inside of automotive glass with a dark pigment. Therefore, you can install tint just like any other glass.
In United States, these percentage means visible light transmission (VLT). A 35% VLT means 35% of visible light is transmitting through the glass whereas a 20% VLT means only 20% is passing through. Therefore, the 20% VLT tint is darker.
Most of the factory tint on the clear glass is roughly seventy percent visible light transmission (VLT) and rear factory tint on many trucks and SUVs is roughly at twenty percent VLT. The heat and UV rejections on many factory tints are limited. You can boost the performance of the factory tint without making them noticeably darker by adding a 70% virtually clear or 50% slightly tinted tint on top of the factory tint. On the other hand if you like more privacy, you can choose to add a darker tint. If you add a 35% tint on top of the factory 20% tint for example, it will end up at roughly 7%. The equation is 35 x 20/100 = 7% VLT.
Most of the factory tint on the clear glass is roughly seventy percent visible light transmission (VLT) and rear factory tint on many trucks and SUVs is roughly at twenty percent VLT. The heat and UV rejections on many factory tints are limited. You can boost the performance of the factory tint without making them noticeably darker by adding a 70% virtually clear or 50% slightly tinted tint on top of the factory tint. On the other hand if you like more privacy, you can choose to add a darker tint. If you add a 35% tint on top of the factory 20% tint for example, it will end up at roughly 7%. The equation is 35 x 20/100 = 7% VLT.
You can tint over custom tint. Surface of the custom tint is more tacky versus glass. When mixing the application solution, please add more concentrated application solution or baby shampoo to the water.