How is ink adhesion tested on printed glass?

Ink adhesion is tested by cross-cut according to ASTM D3359 using 3M 600 tape. Typical criteria are: 5B—no peeling; 4B—less than 5% peeling for black, white, or gray; and 3B—5–15% peeling for overlapping multicolor inks. Special metallic, mirror silver, IR semi-transparent, and similar inks may be tested directly with 3M 600 tape without cross-cutting, with no peeling allowed.