Recto: Right hand page of an open publication.
Registration Marks: Crosses or other marks placed on artwork which ensure perfect alignment ('registration'). Also known as trim marks or crop marks.
Reversed-Out: Type appearing white on a black or colour background, either a solid or a tint.
Resolution: the number of dots per inch (dpi) in a computer-processed document. the level of detail retained by a printed document increases with higher resolution. ppi (pixels per inch) for an image.
RGB: An acronym for red, green and blue. RGB is a colour model used for computer monitors and colour video output systems. colour separations for litho printing can not be made directly from RGB files and need to be converted to CMYK first.
RIP (raster image processor): Computer used to create an electronic bitmap for actual output. this may be built into an imagesetter or may be separate.
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.