Offset printing is a traditional printing method that involves transferring an inked image from a plate onto a rubber blanket, and then onto the printing surface, usually paper. It’s called “offset” because the ink is not directly applied to the paper; instead, it’s transferred (or offset) onto another surface before being applied to the paper.

Here’s how offset printing works:

1. Plate Preparation: The image to be printed is first transferred onto a printing plate. This is typically done using a photosensitive process where the image areas attract ink and the non-image areas repel ink. Each color in the final image requires a separate plate.

2. Ink Application: Ink is applied to the plate, where it adheres to the image areas. The non-image areas of the plate are kept moist with water, which repels the ink.

3. Transfer to Blanket: The inked image is then transferred from the plate onto a rubber blanket cylinder. The rubber blanket conforms to the texture of the printing surface and receives the inked image from the plate.

4. Printing: Finally, the inked image is transferred from the blanket cylinder onto the paper as it passes between the blanket cylinder and a counter-pressure cylinder. This process repeats for each color in the image, with precise registration to ensure that all colors align correctly.