Offset. Alternate term often used for Setoff.
Offset paper. Alternate term often used for Uncoated book paper
Offset powder.Fine powder sprayed on freshly printed sheets to prevent transfer of wet ink as they accumulate in the delivery stack.
Offset printing. Method of lithographic printing that transfers ink from a plate to a blanket, then from the blanket to paper.
OK sheet.Printed sheet representing final inking adjustments approved before production run begins.
Opacity. Characteristic of paper that helps prevent printing on one side from showing on the other.
Opaque. Not transparent. Also, a verb meaning to cover flaws in negatives with paint or tape. Also, the paint used for this purpose.
Opaque ink.Heavily pigmented ink that blocks out color of underlying ink or paper.
Open web.Web press without a drying oven. thus unable to print on coated paper.
Outline halftone.Halftone in which background has been removed to isolate or silhouette an image.
Overlay. Sheet of tissue or acetate taped to a mechanical so that it covers the mounting board.
Overlay proof.Color proof consisting of acetate sheets covering each other in register, one for each color to be printed.
Overprint. To print over a previously printed image.
Overrun. The number of pieces that were printed in excess of the quantity specified.
Overs.Printed pieces in an overrun.