Why print proofing deserves its own checklist
A QR code that looks perfect on screen can fail on paper, and the failure is usually discovered by the customer, not the printer. Screens are backlit, high-contrast, and perfectly flat. Print is none of those things. Ink spreads on uncoated stock, laminate adds glare, folding puts a crease through the code, and trimming shaves the quiet zone. A proof checklist exists to force the physical checks that a screen review cannot perform — on the final proof, on the final stock, before the run.
Size is the first check because it is the easiest to get wrong under layout pressure. A code sized for a poster gets squeezed to fit a flyer; a code sized for a flyer gets squeezed onto a business card. Each squeeze shrinks the modules and narrows the margin for every other error. Check the printed size against the plan with a ruler, not by eye, and scan the proof at the distance the audience will actually use. A code that scans from a desk chair may fail at poster distance, and a code that scans at poster distance may fail when a customer holds a card at arm's length.
Contrast and the quiet zone are the next pair, and they fail together. Designers love reversed codes, coloured codes, and codes tucked against photography — and each of those choices eats into the scanner's ability to find the pattern. Dark modules on a light background remain the safest choice; anything else needs a physical test, not an opinion. The quiet zone — four modules of clear space on every side — is the scanner's frame of reference. Cropping it or letting graphics touch the finder squares is the single most common print failure, and it looks like a bad code rather than a bad margin.
Test scans are where the checklist earns its keep. Scan with an iPhone and an Android device, because their camera pipelines differ. Scan with the oldest phone the audience might carry, because it has the weakest autofocus and the worst low-light behaviour. Scan after lamination and after mounting behind glass, because both add reflections that did not exist on the screen proof. Scan from a slight angle, as a passerby would. And scan the destination on a slow connection, because a code that opens a page that never loads has failed just as surely as a code that never scans.
Finally, make the sign-off mean something. Two signatures — one for the artwork, one for the destination — catch the two different kinds of mistake: the code that is beautifully printed and points at the wrong page, and the code that points at the right page and cannot be scanned. Keep the signed sheet with the job file. When a customer reports a dead code six months later, the sheet tells you what was checked, by whom, and when — and that record is worth more than any apology.