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Glossary

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RADIATION CURING
Inks have been developed to eliminate solvents (VOCs) when printing by web offset, by having the ability built into the ink to become a hardened image; 100% of the ink composition becomes hardened into the dried ink film. Generally the hardening reaction is triggered by either exposure to Ultra Violet radiation (UV) or to an Electron Beam (EB). The same types of materials and principles have been applied to what is called 100% solids coating.

RAG
Formerly the principal raw material used in the making process; often meaning cotton rags. Rag content describes the amount of cotton fiber 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 PAPER
See cotton fiber paper.

RAGGED
Can be "ragged left" or "ragged right"; line and type that has been "justified" to the right or left only, with the opposite side being left uneven or "ragged."

RATTLE
The crisp, crackling sound produced by shaking or crumpling a sheet of paper to indicate its rigidity or stiffness.

RAW STOCK
The paper to which coating is applied.

REAM
500 sheets of paper. Sheet count of paper (500 sheets for most fine papers); see basis weight.

REAM WEIGHT
The weight of one ream of paper, either actual or nominal. The amount that one ream of a particular paper weighs.

RECESSED PRINTING
See gravure printing and engraving.

RECLAIMED FIBER
Recovered fiber in a pure or usable form obtained from refuse matter.

RECOVERY SYSTEM
System in a pulp mill where black liquor is burned and inorganic chemicals are recovered and circulated in the process.

RECYCLABLE SYMBOL
Symbol used to indicate that the paper may be used in the recycling process.

RECYCLE
To reuse, or to use over and over; see de-inking.

RECYCLED CONTENT PAPER
A paper product containing some, but consisting of less than 100% recovered fibers.

RECYCLED FIBER
Cellulose fiber reclaimed from waste material and reused, sometimes with a minor portion of virgin material, to produce new paper.

RECYCLED PAPER
EPA defines this as paper including postconsumer and preconsumer wastes, which are made from at least 50% waste paper.

RECYCLED SYMBOL
Symbol used to indicate that the paper is made from recycled fibers. The percentage of paper of which the fibrous composition contains recovered or recycled cellulose fibers (RCF).

REDUCERS
Materials that are added to inks to reduce either ink tack or viscosity.

REEL
The untrimmed roll of paper that is wound on the full-width shaft at the paper machine dry end. A roll of paper.

REFERENCE BOOKS
The category of books which are produced for reference such as encyclopedias, dictionaries, law books, etc.

REFINER MACHANICAL PULP (RMP)
Pulp made by processing untreated wood chips in mechanical atmospheric refiners. mechanical pulp obtained by first chipping the wood, then separating the cellulose fibers by mechanical rotary refiners. See groundwood.

REFINING
The process of increasing the surface area of cellulose fibers to multiply the number of contact points between them to facilitate their intertwining. Imparts such characteristics as increased capacity to absorb water and improved sheet formation. See cellulose fibers and furnish, the process of preparing cellulose fibers for the making of paper, by mechanical action, whereby the individual fibers are separated from each other, flattened, and roughened (see fibrillation) to various degrees, to obtain the desired final paper properties. The flattening action was earlier referred to as "beating" the fibers, and was accomplished in equipment called "beaters," in a batch process. Today, most refining is continuous, by means of rotating, close clearance steel bars (plates); disk refiners are the more modern equipment, used today.

REFLECTANCE
The percent of incident light reflected from an image area, where zero percent reflectance is black and 100 percent is white; see image density.

REFRACTIVE
Ability to bend light from a straight course. Materials differ in refractivity, which is measured as "refractive index." The refractive index of materials used in the furnish to make paper, will to a great extent determine the differences in opacity of various types of paper, at equivalent basis weights.

REGISTER
The correct position of printing on paper and the correct position of each color in multi-color printing. 1) Paper: a type of bond paper for multi-ply form use; i.e. register bond. 2) Printing: when a design or form is printed in parts or steps, as in multiple colors, it is essential that all parts or inks down match exactly. When they do, they are "in register" or in registration; otherwise, they are "out of register"; see hairline and commercial register.

REGISTER MARKS
Fine lines crossing at right angles and placed on original copy before color separation. Used for positioning images, registering colors, accurate cutting, etc.

RELATIVE HUMIDITY (RH)
The amount of water vapor present in the air as compared to the maximum potential amount. Percent of moisture in the air, relative to the amount of moisture it can hold without precipitation, at any given temperature measured with a psychrometer; humidity or absolute humidity is a measure of the grains of moisture per unit volume of air.

RELEASE PAPER
Papers designed to be stripped away or released from another surface.

RELIEF PRINTING
See letterpress and flexographic printing.

REMAKE
An order entered to supplement an item which was manufactured at insufficient quantity.

REPLACEMENT ORDER
Order entered to replace paper shipped which has proven inferior or damaged.

REPROGRAPHY
Copying and duplicating.

RESERVATION
Systematic allocation of paper machine capacity by a manufacturer on a customer-by-customer basis according to historical buying patterns. This process typically enacted during tight market conditions, ensures the manufacturer will be able to keep integrity within the order scheduling process while providing regular product availability to standard customers.

RESIN
The vegetable excretion or exudation that results in an amorphous, lustrous-appearing, solid organic substance that is soluble in organic solvents.

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

RETENTION AIDS
Materials added to the furnish of a paper machine, to help in keeping the fine particles of the furnish, with and in the formed wet mat of paper on the wire; this is to reduce losses and to retain the fines for the properties they can impart to the finished sheet of paper.

REVERSE EMBOSSING
A printing defect in which the stresses created in the separation of the paper from the blanket stretches the paper and actually raises the printed surface in the image areas (and generally creates a depression on the back), sufficient to distort the sheet of paper and even prevent its laying flat.

REVERSE SEQUENCE
In a multi-ply business form that is to be run once through the printing press or offset duplicator, the sequence (order) of the plies will normally be reversed by running once through the press. After printing, the desired sequence is the usable (crash or straight sequence. See crash sequence). Before printing the sequence is called "reverse" and is a "mirror" of the final desired sequence.

REWINDER
A machine which takes rolls from the reel of the paper machine, the coater, or other winder, and slits and/or rewinds into smaller rolls.

RH
See relative humidity.

RIDGE
A ring around the circumference of a roll or an area in a skid of paper in the machine direction that is harder or higher than an adjacent area; also called hard spot.

RIGHT SIDE OF PAPER
The felt side of a sheet. Also, the side on which the watermark, if any, may be read.

RMP
See refiner mechanical pulp.

ROLL CROWN
The surface curvature shape or diameter profile of wide width rolls under high pressure (pli) to compensate for deflection and obtain a level nip or pressure across the full width.

ROLL CURL
Also called wrap curl. See simple curl.

ROLL STAND
Frame and mechanism for supporting a roll of paper as it unwinds and feeds into a coater, printing press, or other converting operation.

ROPE
Also called "corrugation"; bands of relatively uniform width which occur in the machine direction, around the roll of paper, with uniform diagonal marks present in the band. These bands result from wide areas in the cross direction, of caliper differences, resulting in a roll attempting to wind to two different diameters; if tightness of wind is great enough or the caliper differences are accentuated as in large roll diameters, the rope or corrugation can become "set" and be evidenced in the subsequent pile of sheet paper.

ROSETTE PATTERN
When preparing color separations for printing, the screen angles are rotated for each process color ink. A symmetrical (but non-objectionable) "rosette" dot pattern can result, which the eye can merge into smooth color gradations. However, incorrect screening angles or the shifting of the paper during printing can result in objectionable patterns. See moir' patterns.

ROSIN
Material made up of a suspension and used for internal sizing of paper and paperboard. A natural resin obtained from pine trees, and when suitably modified, is used as an internal sizing agent to impart waterproofness to paper; used in acid sizing of paper. See alum.

ROTARY PRESS
A printing press that carries curved plates on a cylinder (or the plate is the surface of the cylinder), as opposed to an older style flatbed press, using flat plates and type. All elements of the press are cylindrical in shape.

ROTOGRAVURE
Web gravure printing using rotary equipment. See gravure printing.

ROUGH FRONT BOOK
A book with untrimmed pages along its front.

RUBINE
A pigment somewhat redder than true magenta.

RUNNABILITY
Paper properties that affect the ability of the paper to run on the printing press. Paper properties that effect the ability of the paper to run on coating, converting, or printing equipment.

RUNNING HEAD
A title at the top of a page that appears on all pages of a book or chapter in a book.


 
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