Using the ASTM D4400 standard, the paint anti-sagging test method is used, which is a descending blade with a series of continuous high clearances. The notch gap is related to the degree of depression and provides a numerical value called the anti-sag index. The higher the anti-sag index, the better the anti-sag performance of the coating. The development of the instrument and the versatility of its control and research have been described in published reports. Official Digest (JCT), October 1962. Official Digest (JCT), January 1964. Known as ASTM Method D 4400 and Federal Federal Reserve, Method 141 Test Method 4494, the anti-sag instrument is an important piece of equipment in paint laboratories in the United States and around the world.