I'm probably going to embarrass myself now, but here goes anyway. I'm totally new to detailing and have just been one of those guys that was a sponge and bucket once a month person in the past. My question is about paint depth gauges. How do they work exactly? What I mean is, obviously it tells you how deep the paint is on the panel, but does it differentiate between lacquer, colour and primer. If I put a gauge on a panel and it gives a reading saying that there's loads of paint to play with when machine polishing, how do I know it's not 4 coats of primer and the lacquer and top coat are actually really thin? I know this is probably a stupid question to those of you in the know, but like I said, I'm new to all this and it's been something I've been trying to figure out.