Coating is a material that can be applied on the surface of objects, and can bond well with it and form a complete and strong protective film. It has many functions like protection, decoration and other special applications. Based on the form of coatings, it can be divided into water-based coatings, solvent-based coatings, powder coatings, high-solid coatings (including light-curing coatings), etc. Ink, which is composed of binders (resins), pigments, fillers, additives and solvents, etc., can express patterns and characters on the substrate by printing or spraying. It is normally used in books, packaging and decoration, architectural decoration and electronic circuit boards. print. According to different printing types, it can be divided into letterpress ink, lithographic ink, gravure ink, and mesh ink. Also, it can be divided into solvent-based ink, water-based ink, light-curable ink based on the form.