R

rag paper - Today it is usually referred to as cotton fiber paper. It is made from cotton cuttings and linters.

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

random watermark - See watermark.

ream - Five hundred sheets of printing paper.

ream marked - 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 - Weight of a given ream of paper.

ream wrapped - Paper which has been separated into reams and individually packaged or wrapped.

recycled paper - Paper made from old paper pulp; used paper is cooked in chemicals and reduced back to pulp, after it is de-inked.

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).

refining - The mechanical treatment of pulp fibers to develop their papermaking properties.

reflection copy - In photography, illustrative copy that is viewed and must be photographed by light reflected from its surface. Examples are photographs, drawings, etc.

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.

relative humidity (RH) - The amount of water vapor present in the atmosphere expressed as a percentage of the maximum that could be present at the same temperature.

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.

retarders - Chemicals that slow setting time of printing inks.

reverse - When the background is completely printed, and the design area is left unprinted.

rewinder - Equipment which slits and rewinds paper webs into smaller rolls.

right side of paper - The felt side of a sheet, also the side on which the watermark, if any, may be read.

right-angle fold - Term used for two or more folds that are at 90 degree angles to each other.

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

rigidity - Stiffness, resistance to bending.

roll - Web of paper. Paper wound around a core or shaft to form a continuous roll or web of paper.

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

rosin size - A size added to paper to make it water resistant.

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. (Letterhead image is raised, the offset image is flat).

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.

rubylith - A separable two-layer acetate film of red or amber emulsion on a clear base. It has many uses in graphics, most often for color separations by hand in the composition or stripping departments.

rule weight - Thickness of lines; hairline rule; medium rule (1/2 point); heavy rule (1 point).

runnability - Paper’s performance on a press and its ability to withstand the stresses of a running press unaltered. Not the same as printability.