Cross-hatch adhesion test.

A lattice of cuts is scored through the ink down to the substrate, pressure-sensitive tape is rubbed down over the grid and pulled off, and whatever lifts with it is compared against reference pictures. Two standards cover it on opposite scales: ASTM D3359 Test Method B rates 5B down to 0B with 5B as nothing removed, while ISO 2409 rates 0 to 5 with 0 as the good end. They are similar but not technically equivalent, and the details that move the answer differ, including cut spacing set by film thickness, tape pulled at 180 degrees against roughly 60 degrees, and a dwell of 90 seconds against five minutes. D3359 is written for metallic substrates, so a bare claim that a plastic or glass panel passed the cross-hatch, with no standard, spacing or rating attached, is worth nothing when the customer's lab runs the other scale and rejects the batch you already shipped.