Glossary
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- OCR
- Acronym for Optical Character Reader: a device that allows a computer to read printed or written information.OCR Paper especially used for capturing information to be read by an OCR reader. The paper must be clean of dirt spots and is made without optical brighteers.
- Off loading
- Relieving the intensive amount of data processing associated with a specific application (i.e.graphics) from the CPU, by performing those calculations in a dedicated or specialised processor.
- Off-press proofs
- Proofs made by photomechanical or digital means in less time and at a lower cost that press proofs.
- Offset
- 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 paper is specifically made to be printed by the offset process. Today the majority of sheeted paper is made suitable for offset printing. Heavier weights are known as offset cartridge.
- One sided
- Single sided in paper denoting that one side is the printing side. E.g. one side coated.
- Opacity
- The property of paper, which minimises the show-through of printing from the backside 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, which makes it less transparent.
- Opaque ink
- An ink that conceals all colours beneath it.
- Optical Brighteners
- A chemical substance used to increase the apparent whiteness of paper. Also used in printing coatings to give the finished product a whiter appearance.The chemical substance reflects ultraviolet light in the blue end of the visible spectrum, thus increasing the amount of visible light reflected. Papers containing optical brightners will appear different under daylight, flourescent or incandescent light.
- Overhang cover
- A cover larger in size than the pages it encloses.
- Overlay
- In artwork. A transparent covering over the copy where colour break, instructions or corrections are marked. Also, transparent or translucent prints which, when placed one on the other, form a composite picture.
- Overprinting
- Double printing; printing over an area that already has been printed.
- Overrun
- In printing, copies printed in excess of the specified quantity.
- Oxygen Bleaching
- An addition to the conventional chemical bleaching process using oxygen gas to reduce the lignin content, and make waste water treatment easier.