In binding, a booklet bound on the short dimension.
Off-Press Proofs
Proofs made by photomechanical or digital means in less time and at lower cost than press proofs.
Offline
Pertaining to equipment not under direct control of the central processing unit.
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. Short for offset lithography.
Offset Lithography (photolithography, offset)
The most common form of lithographic printing in which the image area and the nonimage area exist on the same plane (plate), separated by chemical repulsion. To print, the ink is "offset" (transferred) from the plate onto a rubber blanket...
Offset Paper
Coated or uncoated paper specifically for offset printing.
Offset Press (sheet fed)
Indirect rotary press with plate cylinder, blanket cylinder and an impression cylinder.
Offset Printing
Process of printing utilizing a lithographic plate on which the images or designs are ink receptive while the remainder of the plate is water receptive. Ink is transferred from the plate to a rubber blanket on the printing press and...
One-Up, Two-Up, etc
Printing one (two, three, etc.) impressions of a job at a time.
Onionskin
A lightweight, cockle finish paper used for making copies of correspondence.
Online
Pertaining to equipment under direct control of the central processing unit of a computer.
Opacity
The amount of "show through" in a sheet from one side to the other. The higher the opacity the less likely that the printing on one side will be visible from the other side.
Opaque
The more opaque a sheet of paper is, the less transparent it is. High opacity in printing papers is a good characteristic as print from the other side of a printed leaf has less "show-through".
Opaque Ink
An ink that conceals all color beneath it.
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...
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 granular surface on coated or printed paper that looks like orange peel.
Out-of-Register
(1) Descriptive of pages on both sides of the sheet which do not back up accurately. (2) Two or more colors are not in the proper position when printed; register does not "match."
Out-of-Round Rolls
Paper rolls that are not suitable for the web offset press because they are not perfectly round and will cause uneven feeding tension.
Out-of-Square
Refers to paper that has been trimmed improperly thus causing the corners to be less or more than 90 degrees. This leads to difficulty during the printing process and often results in misregister of the printed piece. Also called off-square.
Outline Halftone (silhouette halftone)
A halftone image which is outlined by removing the dots that surround it.
Overhang Cover
A cover larger in size than the pages it encloses.
Overinked
Describes printing when too much ink has been used, resulting in heavy print that tends to blur toward the back of the press sheet.
Overpacking
Packing the plate or blanket to a level that is excessively above the level of the cylinder bearer.
Overpressure
Too much pressure, causing ink to tend to plug letters, especially halftone dots.
Overprinting
Double printing; printing over an area that already has been printed.
Overrun
Quantity of paper that is manufactured beyond the quantity specified. In printing, copies printed in excess of the specified quantity.
Oxidation
A chemical reaction which hardens the ink vehicle and makes the film of ink reasonably rub-proof. The process of combining with oxygen.