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Paper & Pulp Dictionary Glossary "O"

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 Definitions for commonly used terms, words and phrases used in the pulp and paper trade



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Odd Lot
Off standard paper. Also the term used for side rolls or sheet left after cutting standard size/order.
Off-machine Coating
Coating of paper on a separate coating machine.
Off-machine Creping
A method whereby paper is creped in a separate operation rather than by the paper machine's Yankee cylinder.
Offset Paper
Also known as book paper. General description of any paper primarily suited for offset printing. Can be coated or uncoated. Characterized by strength, dimensional stability, lack of curl and freedom from foreign surface material. Finish can be vellum or smooth.
Offset Printing
Also know as web offset or lithography. Offers highest degree of precision, clarity, and quality.
Old Corrugated Container (OCC)
Brown boxes that have been used for their intended purpose, then collected for recycling.
On Machine Coating
Application of coating to the paper off the paper machine, or as a separate operation to the papermaking.
Optical Brightener
Fluorescent dyes added to paper to enhance the visual brightness; the dye absorbs ultraviolet light and re-emits it in the visual spectrum.
That properties of paper which minimizes the "show-through" of printing from the backside or the next sheet. The higher the opacity the less likely that the printing on one side will be visible from the other side.
Open End Envelope
An envelope that opens on the short dimension.
Optical Brightness
Optical brighteners or fluorescent dyes are extensively used to make high, bright blue - white papers. They absorb invisible ultraviolet light and convert to visible light, falling into the blue to violet portion of the spectrum, which is then reflected back to our eyes.
Optical Whitener 
A dye that is added to the fiber stock or applied to the paper surface at the size press to enhance its brightness.
Orange Peel
A type of sheet surface that looks like orange.
Organosolv Pulping
Pulping method using organic solvent, e.g. organic acid or alcohol, as delignification/cooking chemical.
Out of Square
Paper which is trimmed improperly so the corners are not true 90 degrees. This will result in difficulty when the presser does not have a good guide edge to work from for accurate register.
Out Turn Sheet
A sheet of paper, taken during manufacture, serving as a reference for the mill or client.
Oven Dry Moisture Content
The percentage loss in weight of a paper specimen when dried to constant weight in an oven maintained at the temperature of 105 +/- 2 C.
Oxygen Bleaching
A process in which pulp is initially treated with oxygen followed by 4-5 bleaching stages.
Oxygen Delignification
A process in which oxygen gas and sodium hydroxide are used to remove lignin from brown stock.
Ozone (O3)
A highly reactive gas with molecules made up of three oxygen atoms.
Ozone Bleaching
A process that uses ozone to whiten cellulose fibers following the Kraft pulping and oxygen delignification processing.
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