White ink is the clearest print route on matte black, gunmetal, carbon, and other dark metal faces — an opaque layer that gives critical data and branding full contrast without losing the restraint of the base finish. Its real limits are size and distance, and both are approved by scanning a physical sample.
Crisp geometry, fine registration stripes, contrast pairs, and a data-matrix zone — white ink at work on dark metal.
White is the workhorse on dark metal: the only print route that holds full contrast on matte black, gunmetal, and carbon faces. The practical limits are size and distance — the smallest text and the QR zone are approved by scanning a physical sample at the real working distance, because a code that scans at arm's length on screen can fail at a gate.
Approve opacity, smallest readable data, QR scan distance, and edge sharpness on the final metal surface.
The practical route is selected from the system, audience, and handling context before the final metal finish and mark treatment are approved.
Metal card production should confirm body construction, finish, chip route, data handling, marking layers, and approval samples in one brief.
Small enough for serials and dense QR zones — but the real limit is set by scanning the physical sample at working distance, and that check is part of every white-ink approval.
The dark ones: matte black, gunmetal, and carbon faces, where any other print route loses contrast. On pale metal, white ink becomes a subtle accent rather than the data carrier.
No — it is a surface layer. The QR panel's position is planned with the artwork so codes sit clear of edge treatments and stay scannable on the finished, reader-tested card.