Sag is considered a paint defect, especially on vertical surfaces, edges and corners of the workpiece. Common terms such as streaks or tear stains describe this flawed appearance very vividly.

| order number | groove depth | Division value |
| PS 2522/1 | 50-275μm | 25μm |
| PS 2522/2 | 250-475μm | 25μm |
| PS 2522/3 | 450-1000μm | 50/100μm |
| Other parameters | ||
| Standards | GB/T 9264, ISO 16862, ASTM D 4400, D 3730 | |
| number of grooves | 10 | |
Ten stripes of various film thicknesses were produced with sag coating.
Immediately after coating, place the test panel in a vertical position with the thinnest film stripe on top and avoid vibration. The convergence of the stripes depends on the tendency to sag.
It is very difficult to reproduce the results of the experiment.
It is very important to ensure the following conditions in the test: stable climate environment, uniformity of coating film, and set evaluation time.
GB/T 9264
ISO 16862
ASTMD 4400, D 3730