Test Step 1:

Test adhesion of the white ink. It is common practice to put materials which print on white ink (such as glass, tiles, etc.) into the water for soaking, 2 hours later, take the material out with your fingers to scraping, if you can gently scrape off, the adhesion and waterproof of white ink is poor, need to replace the new white ink.

Test Step 2:

Test Step 3: