Offset printing

(or offset lithography) is the most common printing method for large print runs, such as newspapers, brochures and books.
The method is called ”offset” because the ink is not transferred directly from the printing plate to the paper, but via an intermediate step.
The technology is based on the chemical principle that oil (paint) and water do not mix. 
  1. Printing plates:
    For each colour (usually CMYK: cyan, magenta, yellow and black), a thin aluminium plate is created.
  2. Colouring:
    The plate is moistened with water, which only sticks to the areas that are not to be coloured. Oil-based paint is then applied, which only adheres to the dry areas (the motif).
  3. Transfer (Offset):
    The paint is first transferred from the plate to a rubber sheet.
  4. Printing:
    The rubber sheet then presses the motif onto the paper. This protects the plate from wear and tear and allows printing on rougher surfaces.     
Advantages and disadvantages

Advantages:

  • Low cost for large volumes: Once the plates have been made, the unit cost per printed item is very low.
  • High quality: Provides sharp details and highly accurate colour reproduction.
  • Material selection: Works on many different types of paper and surfaces.

Disadvantages:

  • High initial cost: Setting up the press and manufacturing plates is expensive and time-consuming, making it unprofitable for small print runs.
  • Longer lead time: It takes time to prepare the print compared to digital printing. 
For smaller print runs (under approx. 500–1,000 copies), the following is usually used digital printing instead.