window tint

I fail to see where I have it backwards, I think you do. Look at it this way, if you take a piece of cardboard and cover a window by 30%, you then have 70% of the window open or unobstructed. Tinting a window is no different.

 

Then why is 5% ,"limo tint", some of the darkest tint available? Why? Because it allows 5% of the light through thus blocking out 95% of the light.

http://www.precuttints.com/darkness-chart

If you only tint 95% of your window with 5% tint that 95% is still tinted at 5%.

Oh and in your cardboard example it would be considered 0% because the cardboard doesn't allow any light through it.

 

Sorry I had to edit as I had my numbers backwards. "If you put 70% on top of installed glass which does have some tint already, than it will exceed the law as 70% allows 70% of the light to come through. Basically if a meter is placed on the inside of the glass and can not pickup at least 70% of light than it is illegal. In other words, if the meter gets 69% than a ticket can be written.

Btw, I found an article relating to this matter and where the FMCSA comments regarding the issue.

http://www.ccjdigital.com/fmcsa-oks-window-tinting-on-commercial-vehicles/

 

5% allows 5% of light through based on VLT (visual light Transmission) so 95% of the light is blocked.
30% allows 30% of the light through, 70% of the light is blocked
70% allows 70% of the light through, 30% of the light is blocked.

The best way to tint a window is to find out the factory tint and than go from there. If the tint from factory is say 90% tint than 10% of light is blocked and you could only add up to say 80% tint which I am not sure they make...but I hope I got the point across. Also based on the FMCSA, if you get a ticket you can call them and make a complaint.

 

Oscar, tint is rated by transmittance, i. e. How much light passes thru. So the higher numbers are lighter tint.


On a vehicle with factory tint, even a clear sheet of film could drop it below the 70% level, as even 'clear' films and glass block a given percentage of light (Clear glass is normally around 90% in visible light wavelengths. )

I watched a smurf put their toy on the vent window of a brand new Pete, shortly after they started using them. Pulled him around, "too dark." I left before he came in, so don't know how that turned out, but the driver wasn't very amused.

 

So it's backwards of how it should be then, I guess I learned something today.

 

No, it's only backwards of how you think it should be.

 

So what do you think that the FMCSA regs mean when they say 70% of light transmittal is the limit?

Does that mean 30% tinting is permissible?

or does it mean 70% tinting is permissible?

 

That means that 70% TOTAL transmittance is permissible. You can block 30% of the light.

Now, since clear glass is ~90%, and factory tinted is 72-78%, the options are NO tint on factory tinted glass, and something close to 80% on clear glass.

 

Dang it! Double post....