tintmeter

Anyone know about the 3 tint cases before the ninth brought by CHP/ FBI?

No one will get in trouble! 

The difference in reading between green and white LED's is very small, within the margin of error. Thats why meters are spec'ed at +_2%.  Remember also that White LED's are made using blue and yellow orange led chips(depends on LED. Think of the LED bulbs for your house, warm white, cool white etc. with all sorts of varying spectral outputs. The green color of the LED, when chosen properly, is 550nm and is a physical constant of the material used to make the LED)The reason for green goes why back to the 80's when it was in some states laws. It allows you to contest the meter reading in court and use any readily available spectrophotometer to take a comparison measurement(labs, university etc all have lots of them.) Years ago early meters used an incandescent bulb(actually a tail light bulb) as the source. Trouble with bulbs is they produce light by heating a filament to glow white and produce tremendous amounts of infrared light(which you can't see) and a small amount of UV.   Even with filters there still is significant IR and some UV(which is invisible) which then would be blocked by the car window/tint film giving a lower reading. Wouldn't be fair to ticket someone for light you can't even see. 550 is the middle of the human eye sensitivity and is the measurement that the optics industry has used for years. The heat absorbers used in car windows do give it a slight green cast but again it just cause a slight high reading compared to white, once again within the +_2%.  The bigger issue we have found is the spot to spot variability in both auto glass and even worse some tint film. Glass makers goal is to keep spot to spot variation under 3%(the threshold of human perception) for the most part they do a very good job, sadly that can't be said for some film manufacturers. I have seen film with greater than 8% spot to spot variation within 12" on the same piece of film. Doesn't make your job any easier when you buy poor quality film.

As for using the one piece Enforcer II to measure film, thats tough to do. if you look at the this GIF    you can see the on/off switch at the bottom of the slot. You need to hold the film tightly between your two hands and with your third hand slide the film in to depress the switch and keep it depressed till you break the beam. Doable but tough. Other wise it will calibrate with the film inplace and read 100 or if the film is dark the meter will know something is screwed up and throw an E1 error reading.

Sorry for the long kind of technical post. Hope I helped some.

PS CEO sounds great but there are only 12 of us, but, we have made half a million of these things in 29 years, so theres that!

Ed

From time to time we make custom meters for customers.(Each original iPhone 1 display cover glass was tested on our equipment, and still to this day) The "White LED" meters were a custom application for a single client in Japan. They had a car manufacturer trying a new glass with custom additives which create a spectral response unlike any glass previously made. The manufacturer decided that the added cost was not justified so they cancelled the project. All meters shipped worldwide use the same green Led. Hope this helps.

If anyone wishes to discuss this more, email me at Ed@laser-Labs.com

(Can't believe iI've been designing Tint Meters for almost 30 years! Getting old!)

Ed Marcin

CEO

Laser Labs

We updated our list of current US tint laws with links to the state regulations, hope it helps.

If you spot errors or broken links, please let me know.

http://www.laser-labs.com/blogs/us-tint-laws

Couldn't have explained it better, well done Howard