Object-oriented An approach in drawing and layout programs that treats graphics as line and arc segments rather than individual dots. Also called vector-oriented.

Oblong A booklet or catalog bound on the shorter dimension.

OCR (Optical Character Recognition) An electronic means of scanning (reading) copy, and converting the scanned image to an electronic equivalent. The ability to "read" printed text (characters) and convert it to digitized files that can be saved on disk and edited as a text file.

Off loading Relieving the intensive amount of data processing associated with a specific application (i.e., graphics) from the CPU (Central Processing Unit), by performing those calculations in a dedicated or specialized processor.

Off-press proofs Proofs made by photomechanical or digital means in less time and at lower cost than press proofs.

Offset See set-off. In printing, the process of using an intermediate blanket cylinder to transfer an image from the image carrier to the substrate. Also, short for offset lithography.

Offset gravure Printing gravure by the offset principle. Generally done on a flexographic press by converting the anilox roller to a gravure image cylinder and covering the plate cylinder with a solid rubber plate.

Oleophilic Oil receptive. See hydrophobic/hydrophilic.

Oleophobic Oil repellent. See hydrophobic/hydrophilic.

Opacity That property of paper that minimizes the show-through of printing from the back side or the next sheet.

Opaque In photoengraving and offset lithography, to paint out areas on a negative not wanted on the plate. In paper, the property that makes it less transparent.

Opaque ink An ink that conceals all color beneath it.

Open specification A standard that is available to the public with limited restrictions.

OPI (Open Prepress Interface) An extension to PostScript that automatically replaces low-resolution placeholder images with high-resolution images. See APR.

OPP (oriented polypropylene) A type of lamination.

Orthochromatic Photographic surfaces insensitive to red but sensitive to ultraviolet, blue, green, and yellow rays.

Out of the box Refers to an applications’ suitability to be rapidly integrated into an existing system.

Overprinting Double printing; printing over an area that already has been printed.

Overrun Additional copies printed in excess of the specified quantity.

Overs and unders Only digital presses can literally print the number of pieces you order. Other presses will print extra copies (overs) or even print fewer than you order (unders). Printers can print 10% more or less than the quantity you specify, and charge you accordingly. Just be aware of this common practice, especially if you are printing a huge run and do NOT want 10% over, or if your quantity is dangerously close to what you need (say, for a mailing), in which case you don't want to risk running out. Know that you can specify what percentage of overs/unders you will accept.

Overhang cover A cover larger in size than the pages it encloses.

Overlay In artwork, a transparent covering over the copy where color break, instructions, or corrections are marked. Also, transparent or translucent prints that, when placed one on the other, form a composite picture.

Overlay proof A hard copy color proof produced with four dyed or pigmented overlay films.