- Local websites
The fineness of a half-tone is always linked with the viewing distance, the fineness of the mesh and the type of stencil.
The finer the half-tone, the closer the acceptable viewing distance, the coarser the half-tone, the higher the contrast in the printed result. The fineness lies in screen printing between 6 and 48 lines per cm.
To ensure that the stencil material stays supported in the three-quarter tonal values (areas of high coverage), and open in the highlights (areas of low coverage) of the smallest printable dots, the resolution capability of the screen printing mesh also needs to be considered.
Strictly speaking, the diameter of the smallest half-tone dot on the diapositive should be microscopically measured, in order to select a mesh of the correct fineness.
From the examples above, it is clear that the diameter of the smallest printable dot must correspond to two threads plus one mesh opening, if the dot is to be adequately supported and printable. The thinner and finer the mesh, the less the ink deposit. These mesh are therefore better suited for fine half-tone printing.
Mesh with medium thread diameter is preferable for half-tone printing, because it balances the amount of thread with the amount of open surface. The thread thus facilitates optimum support for the dots in three-quarter tonal values, without seriously impairing ink release in the highlights.