Offset printing is a widely used printing technique where the inked image is transferred (or "offset") from a plate to a rubber blanket, then to the printing surface. When used in combination with the lithographic process, which is based on the repulsion of oil and water, the offset technique employs a flat (planographic) image carrier on which the image to be printed obtains ink from ink rollers, while the non-printing area attracts a film of water, keeping the non-printing areas ink-free.

Advantages of offset printing include:

Consistent high image quality. Offset printing produces sharper and cleaner images and type than letterpress printing because the rubber blanket conforms to the texture of the printing surface.

• Quick and easy production of printing plates.
• Longer printing plate life than on direct litho presses because there is no direct contact between the plate and the printing surface.

Also Known As:

• Lithographic
• Offset
• Planographic

Sheet-fed Offset Printing - Beaver Press

http://www.skillsone.com.au/Industry/5/Manufacturing/Video/330/0/The-Digi-Print/

Web-fed Offset Printing - Newspaper Printing

http://au.youtube.com/watch?v=pMvGd9XJaPg