Rag Paper - Stationery or other forms of stock having a strong percentage content of "cotton rags."

Rainbow Fountain - Technique of putting ink colors next to each other in the same ink fountain and oscillating the ink rollers to make the colors merge where they touch, producing a rainbow effect.

Raster Image Processor - Device that translates page description commands into bitmapped information for an output device such as a laser printer or imagesetter.

Reader Spread - Mechanicals made in two page spreads as readers would see the pages, as compared to printer spread.

Ream - 500 sheets of paper.

Recycled Paper - New paper made entirely or in part from old paper.

Reflective Copy - Products, such as fabrics, illustrations and photographic prints, viewed by light reflected from them, as compared to transparent copy. Also called reflex copy.

Register - To place printing properly with regard to the edges of paper and other printing on the same sheet. Such printing is said to be in register.

Register Marks - Cross-hair lines on mechanicals and film that help keep flats, plates, and printing in register. Also called crossmarks and position marks.

Relief Printing - Printing method whose image carriers are surfaces with two levels having inked areas higher than noninked areas. Relief printing includes block printing, flexography and letter press.

Repeatability - Ability of a device, such as an imagesetter, to produce film or plates that yield images in register.

Reprographics - General term for xerography, diazo and other methods of copying used by designers, engineers, architects or for general office use.

Resolution - Sharpness of an image on film, paper, computer screen, disc, tape or other medium.

Resolution Target - An image, such as the GATF Star Target, that permits evaluation of resolution on film, proofs or plates.

Reverse - Type, graphic or illustration reproduced by printing ink around its outline, thus allowing the underlying color or paper to show through and form the image. The image 'reverses out' of the ink color. Also called knockout and liftout.

RGB - Abbreviation for red, green, blue, the additive color primaries.

Right Reading - Copy that reads correctly in the language in which it is written. Also describes a photo whose orientation looks like the original scene, as compared to a flopped image.

Rotary Press - Printing press which passes the substrate between two rotating cylinders when making an impression.

Round Back Bind - To casebind with a rounded (convex) spine, as compared to flat back bind.

Ruby Window - Mask on a mechanical, made with rubylith, that creates a window on film shot from the mechanical.

Rule - Line used as a graphic element to separate or organize copy.

Ruleup - Map or drawing given by a printer to a stripper showing how a printing job must be imposed using a specific press and sheet size. Also called press layout, printer's layout and ruleout.