We use a similar scanner at work (CBP)…
Few tips.
-Sometimes, less pressure gives better quality. We always get people slamming their hands down on the scanners when they do it themselves (I prefer rolling for people since I will get it right). I tell most people just to relax and look at something else besides the screen, because when they try to help… it never helps.
-If your prints aren’t showing up… first thing is to clean the scanner. Personally, I’d do it first just because people are dirty (sorry, people… it’s true). Alcohol wipes work best, but make sure to fan the screen so it dries completely before using.
-Still not showing up… are your hands cold that you feel like a corpse? Like mentioned to rub your nose, I suggest the back of your neck. Or put your hands under your armpits… not inside your shirt to get deodorant on it, but just to warm them up.
-Still problems? If it is the same scanner, there is a metal bar below the lower part of the screen. That’s a ground, which has to have contact to allow the screen to capture your prints. This is also a huge issue with rolls. I will take the off hand and touch that metal while rolling… since it doesn’t turn off the scanner in the process as your finger lifts away.
-Rolls… make sure the print doesn’t shift or drag on the screen. It will not capture correctly. When I roll, I start on the outer edge and roll in (either hand, edge near the pinky, and roll towards the thumb). If you have an issue with your arm/wrist, try the opposite. Another option would be to stand perpendicular to the scanner with your arm out… and allow your shoulder/elbow to rotate with the roll. Again, make sure you are in contact with the ground.
-With the roll procedure, you need an edge of the print to start off with. Again, if it is a similar scanner/program, you’ll hear a beep that the roll has started. Slowly roll the print to the opposite side. Once you get all the characteristics of the print (arch, loop, whorl), you’ll hear a second beep. Lift the finger off the scanner. It should have got the print… but sometimes an odd angle or “smudging” will cause the scan to start over… making the second beep another first. Again if it is the same program, you’ll see a red bar on the first beep… and then a green bar when the second beep.
-Corn Huskers… I never had good experiences with it. Mainly because people decide that more will do better, but those I know who use it regularly… they use as little as possible. We have bottles of that stuff at work, and some senior officers don’t think we’ve ever replaced them. I recommend going to the bathroom and washing with soap/water… then fully drying them. With COVID, I’ve seen good use with hand sanitizer… but again, let your hand dry completely before scanning.
-If none of that works, find an employee and ask for help. Electronic fingerprint scanners aren’t new, and you might get lucky and find an employee that used them in other employment (L/E, for example).