Offset printing (also called lithography) is a sophisticated printing technique that transfers an inked image from a metal plate, onto a rubber blanket (or roller) then onto the printing surface. It is called “offset” because the ink is not directly applied to the paper or other substrate.

Offset printing is used for medium to large print runs.  It starts in the design department with a graphic designer preflighting files to make sure they are print ready. Once ready, the artwork is sent to the prepress department.  In the prepress department, plates are burned by laser etching the print image onto an aluminum plate.  For a full color job, 4 plates are made.  One for each color – cyan, magenta, yellow, and black.

Once plates are burned, the press operator loads paper, adds ink to the press, hangs the plates, and adjusts each color to produce an accurate, vibrant print for the customer. Once the colors are set, the printing begins. As the paper is fed through the press, the ink transfers from the plate, to a rubber blanket then onto the paper.

Once printed, the press deposits the paper on a stack at the end of the press. The sheets are often coated with anti-set-off powder preventing them from smudging and sticking to each other. The sheets sit on a cart to dry for a few hours before heading to the bindery department.

In the bindery department, brochures are folded, books are folded collated and stitched, postcards and flyers are trimmed. Then everything is boxed and prepared for shipping or delivery.