Spec data with vlt variance

[jh812]

So I'm just curious, if the roll of film you receive is let's say 40%. You get the roll in and it meters 45 to 47. Granted there's a 2 to 3% variance on the meter. Should that film still perform the same, or would it be lessened considering the lighter vlt? I'm not going into what film it is or anything because I've seen it with a few different ones. Just more curious than anything.

[whitehog]

I can maybe shed a little light on the question for you. First you have to step away from film companies part numbers as these usually are not the actual stated VLT of the film. Always refer to the spec sheets of the film company and find the actual VLT of the film in question. 

Now, say for instance, you have a 40% VLT film from a manny. This film actually can very up to an industry manufacturing standard of + or - 3% variance in the stated VLT. So a 40% film can actually range from 37%-43% and still be within the industry standard for a 40% film. One of the main reasons for this variance is there would be significant film trashed/scrapped if the tolerances were any tighter. Now factor in that any particular meter could have a + or - 2% to 3% variance and it could possibly read the film as anywhere from 34%-46%.

 

Now, to answer your question. If it is claimed to be a 40% film and it is metering at 45% to 47% there would be some minor lessening of the performance due to the film being a slightly lighter VLT. But, the inverse is also true, if the film is a 40% and is metering around 34% to 37%, it will perform slightly better than the stated performance.

 

I hope that I was adequately able to answer your question. 

[jh812]

That does help. I know really it's probably not going to be a huge difference. Just looking at numbers and there's a difference between 40 and 50. Wanted to make sure I knew actual specs.

[vquestfilms.com]

Depending on the film technology and the application (especially if the sq footage applied is large), a 3% vlt variance can have a significant impact on performance an return on investment.

 

What is even more concerning is the rate of decay or the increase of vlt over time as the film breaks down. The performance can decrease very rapidly. I've seen 40%vlt films turn into 50%vlt films after only 500 hrs of accelerated testing.

[Bham]

Depending on the film technology and the application (especially if the sq footage applied is large), a 3% vlt variance can have a significant impact on performance an return on investment.

 

What is even more concerning is the rate of decay or the increase of vlt over time as the film breaks down. The performance can decrease very rapidly. I've seen 40%vlt films turn into 50%vlt films after only 500 hrs of accelerated testing.

Understood, but with the instability of the elements used to make film,,, wouldn't you say a film that is still optically clear and not bubbling and falling off the window,,,,even if lighter on the VLT after time,,, is still a quality film??

I've seen som films lose in the VLT but never actually fail.

[whitehog]

Depending on the film technology and the application (especially if the sq footage applied is large), a 3% vlt variance can have a significant impact on performance an return on investment.

 

What is even more concerning is the rate of decay or the increase of vlt over time as the film breaks down. The performance can decrease very rapidly. I've seen 40%vlt films turn into 50%vlt films after only 500 hrs of accelerated testing.

Rob's brings up a great point. I generally look at questions from the perspective of it being an automotive film. 

[vquestfilms.com]

 

Depending on the film technology and the application (especially if the sq footage applied is large), a 3% vlt variance can have a significant impact on performance an return on investment.

 

What is even more concerning is the rate of decay or the increase of vlt over time as the film breaks down. The performance can decrease very rapidly. I've seen 40%vlt films turn into 50%vlt films after only 500 hrs of accelerated testing.

Understood, but with the instability of the elements used to make film,,, wouldn't you say a film that is still optically clear and not bubbling and falling off the window,,,,even if lighter on the VLT after time,,, is still a quality film??

I've seen som films lose in the VLT but never actually fail.

 

I'd say it is a film that is sticking to the glass. Quality encompasses more than that though. You need the performance to hold up, especially in flat glass.

[Tintguy1980]

Depending on the film technology and the application (especially if the sq footage applied is large), a 3% vlt variance can have a significant impact on performance an return on investment.

 

What is even more concerning is the rate of decay or the increase of vlt over time as the film breaks down. The performance can decrease very rapidly. I've seen 40%vlt films turn into 50%vlt films after only 500 hrs of accelerated testing.

500hrs = shy of one year real term.

[Bham]

...

[jh812]