In most cases, the main reasons for network expansion and loss are as follows: Incorrect ink film thickness. This is due to the unsuitability of silk fabrics that make up the mesh (its ratio of mesh opening to mesh diameter is incorrect); Incorrect template making process. Including low vacuum pressure during exposure, overexposure and insufficient development; 3. Incorrect squeegee device. Including pressure and speed; 4. Incorrect ink viscosity; 5. Substrate surface characteristics. To ensure the correct halftone reproduction, the acceptable range of dot gain and loss must be measured and standardized. Films with halftone test patterns can be used to determine if a particular mesh can be used to obtain an acceptable tonal range. The device measuring the degree of dot gain and loss is a densitometer. The densitometer can provide halftone coverage or dot percentage information. The percentage here refers to the measured percentage of outlets covered by the printed dot. Most densitometers can measure the dot percentage of positive and halftone prints and then automatically compare the two to directly show the dot gain or loss value. In order to effectively understand the degree of network expansion and compensation network expansion, the network expansion/loss curve must be determined. The screen plate is first exposed using a halftone scale, and the scale is then printed with a suitable ink and substrate. The ruler should contain a minimum of 5 levels (representing halftones from low to high), plus 100% field area. After printing and curing the ruler, measure and record the percentage of outlets in the field, then measure and record the percentage of outlets for each rung. Finally, draw a percentage of the scale network points on the XY plot. The ideal value should be a 45 degree straight line (baseline). For example, assuming that the values ​​in Table 1 are selected, the area of ​​the positive dot area (Af) is the baseline relative to the area of ​​the printed area (Ap). Obtaining Figure 3 through measurement helps to indicate where the deviation is increasing or missing. However, it should be remembered that this curve applies only to a specific composite condition such as screens, stencils, inks, substrates, printing categories, and equipment conditions. If any of the conditions change (for example, the same ink is printed on different substrates in different printing modes), you must create new dot gain/loss curves based on the changed composite conditions. Figure 3 (click to view): Dot gain/loss curve (This plot is drawn using the data in Table 1. This plot shows the same screen, stencil characteristics, printing categories, printing equipment, ink, and substrate conditions. The feature description below.)