Rag pulp
Pulp made by disintegrating new or old cotton or linen rags, and cleaning and bleaching fibers.

Ream
500 sheets of paper.

Ream marked
A pile of paper is ream marked by the insertion of small slips of paper or "ream markers" at intervals of every 500 sheets.

Ream marker
Piece of rectangular shaped paper used to mark off the reams in a stack of paper.

Ream weight
The actual weight in pounds of a ream (500 sheets) of paper.

Ream wrapped
Paper that has been separated into reams and individually packaged or wrapped.

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

Recycleable
This means the product can be recycled. Applies to most paper even if it is coated, waxed or otherwise treated.

Recycled
Paper made at least in part from recovered fibers. There is no universally acceptable definition so requirements vary by specific circumstances. The Environmental Protection Agency (EPA) requires post-consumer content in recycled papers purchased by federal agencies. But the Federal Trade Commission (FTC) does not require post-consumer content in papers labeled recycled. Most U.S. government agencies and companies use the EPA standards, but there is no requirement. In Canada, most companies use the terra-choice definition for recycle, which does require minimum levels of post-consumer fiber.

Recycled content paper
Paper that contains some recovered paper materials. The recycled content is measured as a percentage of the paper's weight.

Reducers
In printing inks, varnishes, solvents, oily or greasy compounds used to reduce the consistency for printing. In photography, chemicals used to reduce the density of negative or positive images or the size of halftone dots (dot etching).

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

Register
In printing, register is the placement of two or more images on the same paper in such a manner as to make them in perfect alignment with each other. When a printing job is in exact register, succeeding forms or colors can be printed in the correct position relative to the images already printed on the sheet.

Register mark
Mark placed on a form to assist in proper positioning of after-printing operations. Two short lines at right angles are called an angle mark. Also, bulls-eye marks placed on camera-ready copy to assist in registration of subsequent operations.

Registration
Alignment of one element of a form in relation to another. Also, alignment of printed images upon the same sheet of paper. Aligning two or more halftones exactly so that the resulting image is sharp and clear.

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.

Repeatability
The ability to keep photo film and the images thereon in proper register. Repeatability is usually measured in micrometers.

Rerun
A term referring to printing again from standing negatives.

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

Retarders
Chemicals that slow setting time of printing inks.

Reverse
Reverse occurs when the background is completely printed and the design area is left unprinted.

RGB (Red, Green and Blue)
The primary additive colors used in display devices and scanners. Commonly used to refer to the color space, mixing system or monitor in color computer graphics.

Rice paper
A common misnomer used to describe lightweight, Oriental papers. Rice alone cannot produce a sheet of paper. Rice-straw is only occasionally mixed with other fibers in papermaking. The name may be derived from the rice sizing once used in Japanese papermaking.

Right side of paper
The felt side of a sheet. Also the side on which the watermark, if any, may be read.

Right-read image
Image similar to the original, or intended, final copy.

Roller stripping
In lithography, a term denoting that the ink does not adhere to the metal ink rollers on a press.

Rosette
The dot cluster pattern created by four-color 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.

Rotary press
Printing press in which the plate is wrapped around a cylinder. There are two types, direct and indirect. Direct presses print with a plate cylinder and an impression cylinder. Indirect rotary presses (sheet-fed offset presses) combine a plate cylinder, a blanket cylinder and an impression cylinder.

Rotogravure
Intaglio process. The image is below the surface of the plate (compared to letterhead image, which is raised, and offset image, which is flat).

Rough
A heavily textured paper surface produced by placing wet sheets of paper against textured blankets or by air drying (or both).

Rub-off
(1) Ink on printed sheets, after sufficient drying, which smears or comes off on the fingers when handled. (2) Ink that comes off the cover during shipment and transfers to other covers, or to the shipping carton or mailer. Also called scuffing.

Rub-proof
In printing, an ink that has reached maximum dryness and does not mar with normal abrasion.

Rule weight
Thickness of lines, e.g., hairline rule, medium rule (1/2 point), heavy rule (1 point).

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 resistance. Not the same as printability.