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Common Terms - R
Rag Paper paper with at least 25% and as much as 100% cotton fibers. see also cotton paper.
Ream a package containing 500 sheets of printing paper.
Ream Weight the actual weight in pounds of a ream (500 sheets) of paper. see also actual weight, basis weight, weight.
Recovered Paper paper that has been separated, diverted, or removed from the solid waste stream.
Recyclable, recycled paper, recycled paper recyclable suited for recycling. This term may be misleading. For example, it may be physically possible to recycle a given material, but if it is too costly to do so, or if a collection process is not in place, recycling may be impossible or economically not feasible.
Recycled Content Paper a paper product containing some, but consisting of less than 100% recovered fiber. Champion Carnival is an example of a recycled content paper. see also de-inking, pre-consumer recovered paper, post-consumer recovered paper, recycled content paper.
Recycled Paper a paper product consisting of 100% recovered fiber. Recovered fiber includes pre- and/or post-consumer sources. Champion Benefit is an example of a !00% recycle paper. see also de-inking, pre-consumer recovered paper, post-consumer recovered paper, recycled content paper.
Refining the process of cutting, breaking, and flattening the cellulose fibers in pulp. In order to form a strong, flexible paper, pulp fibers need to be flattened and frayed. The refiner has metal discs that can be adjusted to create longer or shorter fibers. see also hydropulper, papermaking.
Refractiveness a measure of how much a sheet of paper deflects the light that hits it. The more light a sheet deflects, the greater its refractiveness, allowing a printed image to be more brilliant and detailed. see also brightness, whiteness.
Registration The process of alignment of the different elements in a printing job. Such as the different colored inks on a print job, so they are correctly printed next to each other or over each other . (i.e. If the inks can be seen to overlap improperly or to leave white gaps on the page, the printing is said to be "out of registration" or "poorly registered".)
Relative Humidity balance the relative humidity of the pressroom compared to the relative humidity of the paper to be printed. Relative humidity is a mea- sure of how much moisture air or paper can hold versus how much it is actually holding at a given temperature. Before printing a job, the printer must "cure" the paper by letting it sit, wrapped, in the pressroom for a determined amount of time. This will bring the paper to the same temperature and humidity as the pressroom, helping to prevent several printing problems. For instance, ink on cold paper takes longer to dry than ink on room-temperature paper. Ink on dry paper may "chalk" if the dry paper absorbs the liquid in the pigment before the solid pigments adhere to the paper. Paper with too much humidity will expand, causing it to wrinkle on press. This can cause misalignment and a lack or registration in the printing. see also registration.
Relief a method for printing ink on paper, using type of images that rise above the surface of the printing plate. Ink sits on top of these raised surfaces, and as the paper is pressed onto them it picks up ink. Letterpress, flexography, and rubber stamps all use relief plates. In letterpress, intense pressure can cause images to be slightly debossed or depressed below the surface of the paper. see also flexography, letterpress, plate, printing methods.
Reprographic paper see office reprographic paper.
Resilience the ability of paper to return to its original form after being stressed by bending, stretching, or compressing during the printing and finishing processes. see also bonding strength, dimensional stability, runnability, tensile, strength.
Resin a generic term referring to the materials used by paper manufactures to "size" paper. Rosin, a natural resin from pine trees, is used in the manufacture of acidic paper. Synthetic resins are used in the manufacture of alkaline and acid-free papers. see also acid-free, alkaline papermaking, alum, ingredients of paper, rosin, sizing.
RGB Red Green Blue, the colors used by a computer monitor to create color images on the screen. When all three colors are combined over each other the color of light is white.
Rosette the formation created by the dots that make up four-color images. The dots, in magenta (red), cyan (blue), yellow, and black, overlap each other in a cluster. Because the dots are not perfectly round, and because they are turned at angles to each other, this cluster resembles the arrangement of petals in a rose. see also four-color process.
Rosin a natural resin from pine trees, used to size acidic paper. see also ingredients of paper, resin.
Runnability the ease with which a paper moves through a printing press. For example, offset lithography puts more stress on paper than other printing processes because of: how the paper moves through the press; the great amount of water used in the process; and the tackiness of the inks that are used. In order to have good runnability, paper for offset printing must be strong, have great tear resistance, and possess good dimensional stability. It must also be water resistant and have a strong surface so the paper doesn't pick. Runnability is also a term for measuring the number of mechanical web breaks per 1,000 rolls of paper run on a press. see also dimensional stability, offset, printability.