This process relies on the chemical repulsion between oil and water rather than physical relief to transfer an image. The printing plate has no raised areas like letterpress or recessed grooves like intaglio. Instead, the image area is treated to attract greasy ink, while the non-image area is dampened to repel it.
We use planography for this run since the flat plates are faster to prepare and hold fine detail well on smooth paper.
Offset lithography is the most common commercial application of this chemical principle.
Also heard as
- planographic printing
Related terms
Lithographic
Pertaining to a printing process based on the chemical repulsion of oil and water.
Letterpress
A relief printing process where raised, inked surfaces are pressed directly onto paper.
Intaglio
A printing method where the image is incised into a surface and holds the ink below the plate level.