Calibrating Precision Duplex Printing
Double-sided (duplex) printing is notorious for shifting layouts by a few millimeters. This test uses precise optical targets to help you map the exact misregistration between the front paper feed and the flip mechanism.
The Light Test
Print this page double-sided, then hold it up to a window. The front crosses and back circles should perfectly encapsulate each other. Misalignment means your flip-tray is shifting paper.
Software Shifting
If you notice a consistent 2mm shift left on the back page, you can apply a binding margin offset in Adobe Acrobat or InDesign to mathematically correct the hardware error.
Checking Paper Skew
If the top registration marks align but the bottom ones do not, the paper is rotating as it goes through the duplexer. Check your paper tray guides for a tight fit.
Fixing Bleed-Through
If the back target is heavily visible without holding it to the light, your paper is too thin for duplex printing. Upgrade to paper weighing at least 24 lb (90 GSM).