Does card thickness actually matter for Colorado IDs?
Thickness is the first thing I notice too. If it's flimsy or stiff in the wrong way, I just call it before even looking at the ghost image. For Colorado, the tactile laser engraving on the front actually gives a nice ridge that's hard to fake if they cut corners. I'd honestly take a card that passes scan with a perfect PDF417 but has crappy thickness and it still gets flagged. Cheap polycarbonate mixing is what makes the feel off, so check that edge carefully under 365nm UV light. Too many setups miss it entirely.
Totally agree on thickness—it's the first thing I check when I pick up an ID. If the feel's off, I don't even bother with the rest. For Colorado, I've noticed the tactile laser engraving on the newer ones is a big differentiator too; a lot of fakes skip that and it shows immediately. The ghost image and laser perforation are solid tells, but honestly, my buddy's ID with lazy holograms wouldn't even pass scan with a PDF417 scanner. Thickness just anchors the whole thing.
Yeah, thickness matters more than people think. If it's too thin, it feels off immediately when you handle it, and some bouncers will just fail it based on feel. For Colorado, make sure the ghost image and laser perforation line up right—those are easy tells too. I've seen decent sets that pass 365nm UV light fine but fail on thickness. Also watch for lazy holograms; that's another giveaway once you know what real ones look like.
Bought a set of calipers after reading conflicting advice about card thickness as a quality indicator. Tested four Colorado cards and a genuine card. Here is what the measurements showed and whether thickness is actually a useful test.
Standard card thickness
ISO 7810 specifies that ID-1 format cards — the credit card standard used by all US driver's licenses — should be 0.76mm thick, plus or minus 0.08mm. This is the tolerance range for both genuine and well-produced novelty cards. Any card between 0.68mm and 0.84mm is within the specification range.
What I measured
The genuine Colorado license measured 0.77mm — exactly nominal. The four vendor cards measured 0.75mm, 0.79mm, 0.82mm, and 0.68mm respectively. Three of the four were within specification. The 0.68mm card was on the thin edge of tolerance and felt noticeably lighter than the others when handled, which matched the measurement.
Does it matter in practice?
Thickness within the tolerance range is not detectable by hand. Most people cannot reliably distinguish 0.75mm from 0.80mm through feel alone. The 0.68mm card was perceptibly thin in direct comparison but would not register as unusual in isolation.
Outside the tolerance range is a different story. A card under 0.65mm or over 0.90mm is physically different enough to notice in comparison. Venue staff who handle hundreds of cards per evening develop a sense for this range. Production quality vendors stay within tolerance not because of concern about calipers but because they are using standard card substrate.
Verdict on calipers
Useful for quality evaluation and comparison between cards. Not a field test — you cannot pull out calipers at a bar. As a purchasing decision tool for comparing vendors, the measurement gives you one objective data point. Whether that data point justifies the $15 cost of a basic digital caliper depends on how seriously you take the quality assessment process.