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Glossary

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OCR
Abbreviation for "Optical Character Recognition"; human readable images which are optically scanned (read) by data and word processing machines.

OCR PAPER
Paper made for the specific needs of optical character recognition equipment.

OFF-MACHINE COATING
Indicates the process of applying coating material that is not performed on the paper machine, but as a separate operation.

OFF-SET
See set-off.

OFFSET
The most commonly used indirect printing method, in which an impression of type or a design on a flat plate is printed on a cylinder from which it is impressed upon the surface to be printed. Short for offset lithography, but see offset printing.

OFFSET CORE
A core that is not evenly aligned with the edge of the roll.

OFFSET LITHOGRAPHY
Offset printing has become the commonly used name for this type of planographic printing; also called lithographic or stone printing. The method of printing using a plate in a single plane, where the non- image area is distinguished from the image area by creating water receptive and non-water receptive areas on the plate. Today, this is generally accomplished on metal surfaces, by either light sensitive coatings or electronic methods.

OFFSET PAPER
A printing paper, uncoated or coated made for the requirements of offset printing. See book papers.

OFFSET PRINTING
Also known as indirect printing. The method by which the printing plate is removed from the point of transfer of the printing ink to the paper to be printed, generally by means of a resilient blanket or roll; the resilient blanket or roll actually makes the impression on the paper, thus "offsets" the ink. Unless stated otherwise, can also be specific to the offset lithography or planographic printing process, using a resilient blanket to minimize wear on the plate by the paper being printed.

OFFSET WINDING
Also called staggered winding; frequent or abrupt off-sets on the end of a roll.

OLEOPHILIC
Describes the surface of a material that is easily coated by and is compatible with an organic oil; for the opposite see oleophobic. In offset lithography, the image areas of the plate are very oil receptive or oleophilic.

OLEOPHOBIC
Describes the surface of a material that is not easily coated by and actually repels an organic, non-polar oil; for the opposite see oleophilic. In offset lithography, the non-image areas of the plate have been wet with a water based fountain solution and do not accept the oil based ink and these non-image areas are said to be oleophobic.

ONIONSKIN
A thin, lightweight paper used primarily for typewritten correspondence.

OPACITY
Property of paper which obstructs the passage of light and show-through of printing. The characteristic of paper to block the transmission of light, or the ability to provide (low opacity, like tracing paper) or prevent (high opacity) "show through" of dark printing; the human eye is good at comparing this property, but it can be measured by instrument, and is expressed as a percentage of the light that can not pass through the sheet of paper, i.e., a 98% opacity means that 98% of the light can not pass through the sheet, and is absorbed in or reflected from the incident surface.

OPAQUE INK
An ink that does not allow light to pass through it and "hides" the paper or previous printing under it; normally not used in multicolor process printing, where transparent inks are required. See process inks.

OPAQUES
Papers that have been opacified to achieve a high level of opacity and a minimum amount of show-through.

OPAS
An abbreviation for "On/Off Press Application System," a business unit of the Mead Corporation's Fine Paper Division; it is a patented system and materials which allows printers and converters to produce their own carbonless paper on site, either prior to or during the printing of multiple part or ply business forms.

OPTICAL BRIGHTENERS
See fluorescent dyes.

OPTICAL DENSITY
The intensity of the color or printed image, usually (but not always) referenced to black and/or white.

ORANGE PEEL
A granular or pebble-like textured appearance (like an orange peel) that appears as a defect on the surface of a coated or printed paper.

OSHA
An abbreviation for "Occupational Safety and Health Act" and is a U.S. federal act, with an agency responsible for establishing and enforcing the health and safety standards for all employees of business.

OUT-OF-SQUARE
Sheet paper which is cut or trimmed with other than 90 degree corners, or that is cut non-parallel or not at right angles to the grain of the paper (cut on the bias).

OUTTURN SAMPLE
A representative sample taken from a run of paper or a specified shipment.

OVEN-DRY (OD)
Moisture-free (also bone dry) conditions of pulp and paper. Usually determined by drying a known sample to a constant weight in a completely dry atmosphere at a specified temperature.

OVERCOATING
See varnish.

OVER-PRINT
See desensitize (of CF carbonless papers).

OVERRUN
A quantity of paper made in excess of the amount ordered. Trade customs allow for a certain tolerance for overruns and underruns. A quantity of paper made in excess of the amount ordered; trade practices permit a certain tolerance for overruns and underruns, with the percentage usually dependent upon the size of the order. Also, in printing, copies printed in excess of the quantity ordered.


 
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