Because plastic and glass materials are hard materials, we can use the same hard UV ink, but the coating treatment solution used before printing is different. Because the glass is transparent, it needs to print white ink first and then color ink, or positive image reverse printing first and then color ink, so the effect is more beautiful. There is no need for white color printing according to different needs, such as glass. Relief effect and varnish effect printing are similar, so a UV machine can print different materials such as glass or plastic at the same time.