Printing Glossary – Terms starting with O

# A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Offset

An erroneous variation of the word “setoff”. Ink that is unintentionally transferred from a printed sheet to the back of the sheet above it as the pieces are stacked in a pile when printed.

Offset paper

A term for sometimes used for uncoated book paper.

Offset printing

The most commonly used printing method, where the printed material does not receive ink directly from a printing plate but from an intermediary blanket that receives the ink from the plate and then transfers it to the paper.

Onion Skin

A specific lightweight type (kind) of paper usually used in the past for air mail. Seldom used today (in the typewriter era)

Onionskin

A light bond paper used for typing and used with carbon paper because of its thinness.

Opacity

Quality of papers that defines its opaqueness or ability to prevent two-sided printing from showing through.

Opaque

(1) Not transparent. (2) To cover flaws in negative with tape or opaquing paint. Also called block out and spot

Opaque ink

Ink that completely covers any ink under itself.

Open Prepress Interface

Hardware and software that link desktop publishing systems with color electronic prepress systems

Outer form

Form (side of a press sheet) containing images for the first and last pages of the folded signature (its outside pages) as compared to inner form

Outline Halftone

Halftone in which background has been removed or replaced to isolate or silhouette the main image. Also called knockout halftone and silhouette halftone

Over Run

Additional printed matter beyond order. Overage policy varies in the printing industry. Advance questions avoid blind knowledge

Overlay

Layer of material taped to a mechanical, photo or proof. Acetate overlays are used to separate colors by having some type or art on them instead of on the mounting board. Tissue overlays are used to carry instructions about the underlying copy and to protect the base art

Overlay proof

A process of proof-making whereby the color separations are individually exposed to light sensitive film. This film is then set in registration with a piece of white paper in the background.

Overprint

To print one image over a previously printed image, such as printing type over a screen tint. Also called surprint

Overprinting

Any printing that is done on an area that has already been printed.

Overrun

Quantities of sheets printed over the requested number of copies.