10. Hardness.
The degree to which the ink film is deformed by pressure can be measured with a hardness meter for the paint and coating industry. Starting from the print application, the hardness can also be used to measure the scratch resistance. If the same force is used, the ink film is fully dried (48 hours after printing) with a pencil with different hardness (H), so that the ink can be etched. The H value is the hardness of the measured ink. Hardness is very important for the printing of rigid bodies such as metal, hard plastic and glass.