1. Check the appearance. If the paper appears very white and has a low finish, there could be an issue with its protective coating and thermal coating. Too much phosphor may have been added, causing a good thermal paper to appear slightly green.
2. Roast on fire. Heat the back of the paper with fire to check its color after heating; brownish tints indicate there may be an issue with the heat-sensitive formula and storage time may be reduced. If black parts have thin stripes or uneven color spots, that means uneven coating. Thermal paper with good quality should turn black-green (with some green) after heating, with uniform color blocks fading gradually from center to periphery.
3. Sunlight Contrast Recognition. Highlight the thermal paper printed by barcode printing software with a highlighter and expose it to sunlight. The faster the thermal paper turns black, the shorter its storage time will be.
Zhejiang Lantai Paper Products Co., Ltd. Thermal Labels
