It's more than likely just the contrast off your white sedan compared to his already deep graphite. It's your eyes playing tricks on you

 

It's definitely not a trick on the eyes here, lol. The graphite coupe is mine. Looking at the windows only, you can see a huge difference in the darkness of the tint.

Not all tint is manufactured exactly at the specified darkness, and it will vary from brand to brand.

For example, my 35% tint could actually be closer to 40% and his 35% tint could be closer to 30%. Not all manufacturers make it very clear as to what the exact percentages are, but they typically are not dead on with the marketed percentage.

I just checked my tint (3M Color Stable) and they list that the 35% tint is actually 39% and the 20% tint is actually 19%.

http://multimedia.3m.com/mws/media/6...s-brochure.pdf

 

Definitely a difference in the tiny film itself. Different brands of tint. Just found it interesting.

 

Good point, but if you knew the answer then why say you didnt know why? hahaha jk