Buying My First Airbrush (or Compressor) Questions. in Model Building Questions and Answers Posted Friday at 02:05 PM 10 hours ago, peteski said: What happens to the pressure reading once you stop pressing the trigger? Does it show few psi higher than while you are spraying? Or is the pressure reading steady regardless of whether the air is flowing through the regulator or not? Yes, it goes back up a couple of psi. That's to be expected.