Chapter 5 – Glossary of Prepress Terms

From The Standard, Volume 1, 2005, courtesy of Sappi North America.

Basis weight • The weight in pounds of a ream (500 sheets) of a specific paper grade that has been cut to its basic size.

Binding • The fastening of papers to create a brochure or book. The most common binding styles are saddle-stitch, perfect bound, side-stitched, case or edition, and mechanical.

Bleed • A printed color or image that extends past the trimmed edges of a page, usually an 1/8th inch.

Blueline • Prepress photographic proof made from stripped negatives where all colors show as blue images on white paper. Color digital proofs are beginning to replace bluelines.

Clipping path • A vector-based outline used to “clip” or silhouette an image from its surroundings so only the desired part will print.

Color separation • A laser scanning method used to separate full-color artwork or transparencies into the four primary printing ink colors of cyan, magenta, yellow and black.

Creep • The phenomenon of the middle pages of a folded signature extending slightly beyond the outside pages.

Crop • The blocking out of unwanted parts of an image to fit a layout space or deleting portions that aren’t relevant.

Crossover • An image or type that continues across a spread of a brochure, book or magazine to another page.

CMYK • Acronym for the ink colors used in four-color process printing. The letters stand for cyan, magenta, yellow and key (black). Also called process colors.

DPI (Dots-per-inch) • In offset printing, the number of dots that fit horizontally and vertically into a one-inch measure. Generally, the higher the dpi, the sharper the printed image.

Drawdown • A test of the ink color on the actual paper stock that will be used to evaluate how it looks.

Dry trap • Printing over dry ink, which, unlike a wet trap, requires a separate pass through the press.

EPS (Encapsulated PostScript) • File format for images or graphics. (Editor’s note: EPS has been largely replaced by PDF as a graphics file format.)

Finish • The surface characteristics of paper – such as gloss, matte, silk, velvet, satin, and dull.

Finishing • Post-press operations, including trimming, scoring, folding and binding.

Font • A typeface family that includes all letters and numbers in the same style.

Form • Pages of a book or brochure that are printed on the same sheet of paper as it passes through the press. Once the sheet is folded and trimmed, the form becomes a “signature.”

Four-color process • Method of printing using cyan, magenta, yellow and black (CMYK) inks to simulate full-color images. Also called full-color printing and process printing.

FPO (For Position Only) • Usually a low-resolution image (72 or 100 dpi) file used only to indicate placement and size. It is meant to be replaced by a high-resolution image before printing.

Grindoff • The 1/8th inch along the spine that is ground off of gathered signatures before perfect binding.

Hard copy • A paper printout at 100% size of digital files. It is usually output on a desktop laser or inkjet printer.

Hi-res • High-resolution image, usually 300 to 350 dpi.

Knockout • An area of background color that has been masked out (knocked out) by a foreground object and therefore does not print.

Loose color • Proof of a halftone or color separation that is not assembled with other elements on a page. Also, known as loose or scatter proof.

Low-res • Low-resolution image, such as 72 or 100 dpi.

Mark-up • Instructions written on a hard-copy printout.

Match color • A custom-blended ink color that matches a specified color in a color system such as Pantone®, Toyo® or TruMatch®. It is not built from a combination of CMYK.

Overprint • Printing one ink over another, such as printing type over a screen tint.

PDF (Portable Document Format) • Adobe® Systems file format to facilitate cross-platform viewing of documents in their original form. (Editor’s note: PDF and PDF/X are now used for most print job submissions.)

Prepress • RIPing files, platemaking, and other work performed by the printer, separator or service bureau in preparation for printing.

Process colors • See CMYK.

Proof • Print made from negatives or plates to check for errors and flaws, predict results on press and record how a printing job is intended to appear when finished. (Editor’s note: Proofs are now made almost exclusively from digital files.)

Raster graphics • Computer image made up of pixels. Photoshop® is the most common raster program.

RGB • Red, green and blue – the additive primaries used in monitors. They are not printing colors.

RIP (Raster Image Processor) • This device is designed to interpret PostScript files and create a document suitable for printing.

Service Bureau • Typically an independent business that specializes in preparing digital files for print.

Source File • The original graphic file.

Spot Color or Varnish • Specific color or varnish that is applied only to portions of a sheet.

TIF or TIFF (Tagged Image File Format) • Raster file format used for image placement in page layout programs. TIFs can sometimes be tinted and modified in a page layout program where EPS images cannot.

Trim size • The size of the printed piece in its finished form.

UV coating • Liquid applied to a coated sheet, then bonded and cured with ultraviolet light.

If you find omissions or errors in this list, please let us know: