Mar 10 2010

Glossary of Terms for
Paper and Printing

"R"

RAG

Formerly the principal raw material used in the making process; often meaning cotton rags. Rag content describes the amount of cotton fibre relative to the total amount of material used in the pulp. "Rag content" is not widely used (or is a misnomer) today as more and more high quality paper is made not from rag but from linters.

RAG CONTENT

The amount of rag fibres in a sheet, varying from 25% to 100%.

RAG PAPER

Paper that contains at least 25% cotton fibre.

RAGGED

Text with irregular line lengths set to a maximum width, usually with an even left margin.

RAM

Random Access Memory.

RASTER LINKS

Evenly spaced striations that resemble a corduroy appearance.

REAM

A term denoting a number of sheets of paper ranging from 480 to 516, most commonly 500.

RECOVERED PAPER

Used papers that have been recovered from the solid waste stream in order to recycle them into fresh papers.

RECYCLABLE

Materials suitable for recycling.

RECYCLED

Paper consisting of some amount of recovered or recycled cellulose fibres.

RECYCLED CONTENT PAPER

Paper that contains some recycled fibres.

RECYCLING

The recycling of used product made from paper and cardboard (packaging, newspapers, etc.) is the return of these products into the production cycle of paper-cardboard. In the production process, the raw material is regenerated and converted in similar products. For example, a used cardboard box is turned into a new cardboard box, or old newspapers are reused for producing new newspapers.

REEL

A continuous length of paper wound on a core.

REFRACTIVENESS

A measure of the amount of light deflected off a sheet of paper. Highly refractive papers enhance the brightness and clarity of images.

REGISTRATION

Aligning two or more halftones exactly so that the resulting image is sharp and clear.

RELATIVE HUMIDITY

The mass of water vapour actually contained in a given volume of air expressed as a percentage of the maximum mass of water vapour that could be contained in that same volume at the same temperature.

RELATIVE HUMIDITY BALANCE

Balancing the moisture content in the paper with the humidity and temperature in the pressroom. Paper with too much humidity will expand, causing wrinkling and registration problems during printing. Paper with too little moisture may not absorb inks evenly.

RELIEF

Letterpress, flexography and rubber stamps are all examples of relief printing. Type and images sit above the surface of the printing plate. The relief portion is inked, and paper is pressed against it to reproduce everything that sits above the surface.

RESILIENCE

A paper's ability to return to its original form after being stretched, bent or compressed during the printing and bindery process.

RESOLUTION

The sharpness and clarity of an image.

RETENTION

The percentage of the amount of a loading or additive added to the stock that is retained in the final sheet of paper.

RGB

Red Green Blue. Primary colour of light - used for all photographic and digital capture of coloured imaged by camera and scanners.

RICE PAPER

A common misnomer used to describe Oriental papers. There are no papers made from rice, although rice starch was traditionally used to size papers made of Kozo (mulberry plant), Gampi, or Mitsumata.

RIP

Raster Image Processor.

ROLL SIZE

The width of a roll of paper.

ROM

Read Only Memory.

ROSETTE

The dot cluster pattern created by four-colour process printing. Because the dots are angled and overlap each other, they form a rosette pattern.

ROSIN

A natural resin from pine trees, used to size acidic paper.

ROUGH

A heavily textured paper surface.

RUBBING

The unintentional transfer of ink from one sheet to another, usually associated with uncoated or matt coated paper.

RUN-ON

To continue printing on the same run.

RUNNABILITY

The ease with which a paper moves through a printing press. This is primarily determined by the paper's strength, tear resistance, dimensional stability, bonding strength and water.