offsetlithografi

Offset lithography, often shortened to offset printing, is a widely used commercial printing technique. It is a lithographic process, meaning it relies on the principle that oil and water do not mix. In offset printing, an image is transferred from a plate to a rubber blanket, and then to the printing surface. This indirect transfer is what gives the process its name.

The printing plate, typically made of aluminum, is chemically treated so that the image area attracts ink and repels water, while the non-image area repels ink and attracts water. When the plate is dampened with water, only the non-image areas retain the water. Ink is then applied to the plate, and it adheres only to the image areas. The inked image is then transferred to a rubber blanket cylinder. Finally, the blanket cylinder transfers the image to the paper or other substrate. This three-cylinder system (plate, blanket, and impression cylinder) is characteristic of offset lithography.

Offset printing is known for its high quality, sharp detail, and ability to produce images with consistent color. It is suitable for a wide range of paper stocks and printing applications, from books and magazines to packaging and brochures. The process can be adapted for both sheet-fed and web-fed printing, allowing for high-volume production.