ASTM D 344-97-2004 "Measuring the relative hiding power of coatings by visual evaluation of small area brushing", specifies a standard method for visually assessing the relative hiding power of coatings using small area brushing. The standard specifies the sample preparation, brushing tools and operating specifications, sets the contrast color plate and observation conditions, and visually evaluates the Coating hiding power through the after-brushing coating effect on the base color. It provides a unified detection standard and judgment basis for quickly and intuitively judging the Coating hiding performance.