1. Appearance: If the paper is very white, it means that the protective coating and thermal coating of the paper are unreasonable, and too much phosphor is added, and the better paper should be slightly greenish. The paper does not have a high finish or looks uneven, indicating that the coating of the paper is uneven. If the paper seems to reflect light strongly, too much phosphor has been added, and the quality is not good.
2. Fire roasting: The method of roasting with fire is also very simple. Use a lighter to heat the back of the paper. If the color on the paper is brown after heating, it means that the thermal formula is not reasonable, and the storage time may be relatively short. Small streaks or uneven color patches on the black part of the paper indicate an uneven coating. A better quality paper should be dark green (with a hint of green) when heated, with a uniform color patch that fades from the center to the periphery.
3. Comparison and identification of sunlight exposure: apply the printed paper with a highlighter and place it in the sun (this can speed up the reaction of the heat-sensitive coating to light). Which kind of paper will turn black the fastest, indicating that the longer it can be stored. short.