The transfer of offset printing ink to the printing substrate or intermediate carrier through splitting the ink layer is mainly affected by the following parameters:
- the thickness of the ink layer on the offset printing plates (ink supply),
- the period of contact (printing speed and geometry of the printing components),
- the contact pressure (also called printing pressure),
- the rheological properties of the offset printing inks,
- the temperature ratios (temperature has a marked effect on the ink’s rheological properties),
- the surface properties of the printing substrate and printing plate or intermediate carrier (wettability, absorbency, roughness, etc.).
A further factor influencing the layer of ink on the substrate is the absorption properties of the ink in the printing substrate.
With both absorbent and non-absorbent printing substrates, the ink transfer is reduced if the printing speed is increased, as the period of contact then becomes shorter. In indirect printing, ink transfer takes place in two stages. The layer of ink on the printing plate is brought into contact with a rubber blanket and then part of the ink layer adheres to the blanket. Ink is then transferred to the substrate.