The ASTM D4062-16 standard test method is used to determine the Smoothness of Coatings and to evaluate the degree of surface defects after application. The Smoothness of white and light shaded aqueous and solvent-based architectural coatings is tested by comparing the ridges produced in the Coating film with the standard plastic plate. This method is suitable for evaluating the masking and Appearance Smoothness of Coatings by pull-down film, but not for measuring the sagging tendency of Coatings. The test results help to optimize the application effect of Coatings.