useful information

Glossary - O

Oblique

A slanted character, the sans serif equivalent to italics.

Oblique stroke

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OCR (Optical Character Recognition)

Software such as Omni Page Pro that provides a means of reading printed characters on documents and converting them into editable text rather than just a picture.

OD

Outside diameter of a cylinder, roller or roll of labels.

OEM

Original Equipment Manufacturer. One who produces a component or components used in the making of a finished assembled product.

Office Reprographic Paper

Commonly referred to as reprographic paper, includes a variety of business paper grades (both cut-size and copier rolls), like bond, mimeo, duplicator, and reproduction papers.

Off-machine Coating

Coating paper after it comes off the papermaking machine rather than while it is still on the machine. Off-machine coaters may be used to add a single layer of coating to a paper, or to add a second layer to a paper that has already been machine coated.

Offprint

A run-on or reprint of an article first published in a magazine or journal.

Offset

An indirect printing process. Ink is transferred to paper from a blanket that carries an impression from the printing plate, rather than directly from the printing plate itself. Generally, when we say "offset" we mean "offset lithography," even though other printing processes, such as letterpress, may also use this indirect technique. The term offset (or "set off") can also refer to the smudges created when ink from one printed sheet transfers to another. Offset spray is used to prevent this.

Offset gravure

Primarily done on a flexographic press using the offset principle.

Offset lithography

The method of printing whereby ink is offset from the printing plate to a second roller then to paper.

Offset Papers

Book and text weight papers that are made to withstand the rigors of offset printing. These papers are more resistant to water and less susceptible to picking. Most book and text grades of paper can be used on offset presses. Often the term "offset" is used synonymously with "book." The basic size of off- set papers is 25"x38".

Old style

A 16th Century style of type characterised by stressed strokes and triangular serifs. An example of an old style face is Garamond. One-up, two-upPrinting one (two, three, and so on) impressions at a time in a single job.

Onionskin

A translucent lightweight paper used for airmail stationery.

Ooze

Adhesive moving out of ends of rolls or stacks of sheets causing ends to feel sticky and possible causing material to block.

Oozing

A “squeezing out” of the adhesive from under the backing, occurring when the tape is in roll form, the edges of the roll become tacky.

Opacity

A measure of how opaque a paper is. The more fibers or fillers a paper has, the more opaque it is, and the less it allows "show- through" of the printing on the back side or on the next page. Opacity isn't always determined by thickness or weight; a thinner paper may have more opacity than a thicker paper if opacifying thickeners are used.

Opaque

Opaque: Ink which does not allow the substrate beneath to show through.

Opaque Ink

An ink that conceals all colour beneath it.

Operating Side

That side of a label press on which the printing unit adjustments are located. Opposite of driving side or gear side.

OPI (Open Prepress Initiative)

A method of using small low resolution images in the DTP application and having the appropriate high resolution image obtained by the RIP from a server at output time.

OPP

Oriented polypropylene.

Optical centre

A point above the true centre of the page, which will not appear 'low' as the geometric centre does.

Optical Disks

Videodisks on which large amounts of information can be stored in binary form representing characters of text or images. The disks cannot be used to view the information using a modified compact disk player and TV.

Opticite Film

Trademark of a label film supplied by Dow Chemical (polystyrene type).

Orientation

The alignment of bars and spaces to the scanner. Often referred to as vertical (picket fence) or horizontal (ladder).

Orphan

Line of type on its own at the top or bottom of a page.

Orthochromatic film

“Ortho” film sensitive to blue, green and yellow light that records black-and-white images without tonal gradations. Used in plate making.

OS (Operating System)

As DOS on Windows platforms, and MacOS for Apple Macintosh. Provides basic functionality such as keyboard input, and sending output to a monitor, keeping track of files and their whereabouts and controlling peripherals such as printers and additional hard drives. They also provide the ability for the computer to run applications.

Outline

A typeface in which the characters are formed with the outline only defined rather than from solid strokes.

Out-of-register

When the colours of a printed image are misaligned.

Output device

The final destination for a prepress workflow, usually a laser printer or imagesetter.

Over laminating

Application of clear film to a graphic for the purpose of protection or to enhance the graphic quality.

Over runs

Production beyond the quantity specified.

Overlap

Wrap-around labelling of a container in which one end of the label overlaps the other.

Overlay

Transparent sheet covering a piece of artwork indicating colour separations, corrections or directions to the plate maker.

Overprinting

Printing over an area already printed. Used to emphasise changes or alterations.

Overs

Additional paper required to compensate for spoilage in printing. Also used to refer to a quantity produced above the number of copies ordered.

Overset

Excess type that cannot fit into space specifications.

Overstrike

A method used in word processing to produce a character not in the typeface by superimposing two separate characters, e.g.forming a $ character using the S and l characters.

Oxidizer

A mild chemical solution that causes un-coated areas of brass and aluminium to turn black.

Oxygen Delignification

A processing step that takes place after pulping and before bleaching. Oxygen is used to remove lignin (delignify) resulting in lower chemical usage in the bleach plant.

Ozalid

A trade name to describe a method of copying page proofs from paper or film.