Figuring out tint % needed

[Antwan]

Hi all,

 

Been trying to do research on this and talking to a local reputable shop but can’t get a clear answer. I’m looking to tint my windows to be around 30% with the Llumar pinnacle ceramic tint. My car is currently stock and the windows say “Transp 70% min”. So my question is if I want a 30% tint, does the shop need to apply a 40% tint film to net ~30% (70%x40%)? I asked them about this and they said that’s not how it works and I’m assuming if I asked for 30% they’re just going to apply a 30% film. Will it come out as 30% or 21% based on the calculation? Does the stock 70% not actually need to be accounted for?

 

Any help is appreciated, thanks!

[LeadfootCJ7]

This thread below goes over this topic some.

 

I don't know how dark your factory glass is.  I think that changes from glass to glass so it may be hard to pin down.  Your calculation is correct though.  .70x.40 assuming that 70% is correct for the glass.  

 

 

 

 

Edited April 5, 2023 by LeadfootCJ7

[Tintguy1980]

The calculation used is correct, however, it is not as accurate as light meter. Neither the 30% nor the 40% will get you 30% VLT on an exact 70% VLT glass. There's a +/- 3% manufacturing variation for film products and for glass, exampled here: 1) 30% film could be 27%-33% and 2) 70% glass could be 67%-70%.

 

If your target is to be 30% by calculating (without meter) ... and, glass and film are precise, you would need a film with a precise VLT of 42.9%.

 

Now that this is clear, there's the light meter variance of +/- 2% at full charge battery.

 

Windshields must stay above 70%, that said, car mannies push it all the way to the limit.

 

Side and back glass varies wildly from badge to badge having a base limit of 70% down to 20% (give or take) for solar control privacy glass (this glass, today, can achieve above 60% solar control and 95% UV reduction). I've metered a 2014 Cadi front door at 70% with solar control at 47%. A low end early 2000's Mitsubishi front glass metered at 80%.

 

The newer glass is gaining performance while remaining in the 70% or above, including UV screening. Definitely high values with privacy glass.

 

Keep it legal.

[Ryker]

23 hours ago, Antwan said:

Hi all,

 

Been trying to do research on this and talking to a local reputable shop but can’t get a clear answer. I’m looking to tint my windows to be around 30% with the Llumar pinnacle ceramic tint. My car is currently stock and the windows say “Transp 70% min”. So my question is if I want a 30% tint, does the shop need to apply a 40% tint film to net ~30% (70%x40%)? I asked them about this and they said that’s not how it works and I’m assuming if I asked for 30% they’re just going to apply a 30% film. Will it come out as 30% or 21% based on the calculation? Does the stock 70% not actually need to be accounted for?

 

Any help is appreciated, thanks!

I use global 40% to get in a net 35% here in Illinois.   It will typically meter between 36% and 32%. That gets in the 5% allowed over for legal....

 

So yes,  a true 40% film is the range you want.  Now the fact is you won't likely see a difference if it is between 30 and 38% with your eyes. Meters are the only way...

 

Some vehicles will look darker with a certain darkness than another similar vehicle.  A darker car,  darker interior,  shorter, and or smaller windows... all factors.  Overcast days the windows will look different and harder to see in due to the gray reflection from the sky.

[DynamicATL]

The easiest way is to have the shop cut a small piece to meter on your glass. This will be the only true way to see the final number. Too many variables for any formula to give you exact results.