APR  Automatic picture replacement. A process used on Creo (Scitex) systems where high-resolution scans are made, and specially linked low resolution images are sent to the designer for placement in the layout. The linked low-res images are automatically swapped with the high-res images at when the file is ripped. (Similar to opi.)

Automatic tracing  A function found in illustration software and also available in specialized tracing software like Adobe Streamline. It will automatically trace a scanned line-art image using bezier paths. While fast, it is considered less accurate than manual tracing where the designer traces the scan by hand.

Black point  A scanning term that describes the assigning of solid, neutral, black to the darkest area of a photograph. This causes the other tonal areas to shift so that contrast is maximized. (See "White point.")

Color management  A term for a collection of techniques and technologies designed to make it easier to achieve consistent, predictable color on various display and output devices. Color management relies on automated color conversions using profiles for the various printers and monitors. (See "Profiles.")

Color separation  A term used in desktop image editing software that refers to the act of converting an RGB image to a CMYK image. A prerequisite to this step is establishing proper CMYK conversion setup to include gcr, black ink limit and total ink coverage.

Compositing  An image editing term that refers to assembling multiple images into a single, new, image.

Designer  In this document, the term signifies the person that creates digital mechanicals for print reproduction; the person that makes the files.

DCS  Desktop color separation. A file format for CMYK images where process color information is stored in four separate files. A fifth "master" file is used for placement in a page layout. This format is sometimes used by prepress vendors instead of opi, or apr images. (The master file can be sent to the designer for placement in the layout.)

DCS2  A new version of the DCS file format supporting CMYK and additional spot colors. A DCS2 image can be either the multi file format, or it can contain all separated colors within in a single file.

DPI  Dots per inch. Refers to the laser resolution of a laser printer or imagesetter. This term is sometimes wrongly used to refer to the pixel resolution of a scan. (See "PPI.")

EPS  Encapsulated Postscript. A file format used in desktop publishing; the standard format used by illustration software.

Full tone range  An image editing term that refers to an image that contains tones distributed between pure white and pure black. (See "Tone compression.")

GCR  Gray component replacement. A color separation term referring to the act of removing a percentage of cyan, magenta and yellow inks from an image and replacing them with black ink. This reduces the total amount of ink in the images, allowing better print quality.

Ghosting  An image editing term that refers to reducing the image density in a selected area until it becomes faint and very light. Designers will frequently "ghost" part of an image to allow type to be positioned over the image.

Graphics linking  A page layout term that refers to the way placed graphics files are managed by the software. When a graphic is placed on a page, it appears there but does not become part of the page layout file. The page layout software keEPS track of the location of the graphics file (the link) and will download that file when the page layout is printed.

Imposition  A prepress term referring to the act of arranging individual pages of a job in larger units called flats. These imposed flats are used to generate film or plates.

LPI  Lines per inch. An electronic prepress term used to refer to the halftone screen frequency; which is measured in lines of halftone dots per inch.

OPI  Open prepress interface. A process used on desktop prepress systems where high resolution scans are made and specially linked low resolution images are sent to the designer for placement in the layout. The linked low-res images are automatically swapped with the high-res images when the file is ripped. (Similar to apr.)

Output vendor  In this document the term refers to the organization that uses an imagesetter to create film from a digital mechanical; also called service bureaus or color separation shops.

Overprint  When two items overlap and their inks print on top of each other. The overprint function is activated on an element by element basis in illustration and page layout software and can be selectively applied to the line and/or the fill of the object. Overprinting is the opposite of knockout and can eliminate the need for trapping.

Pixel  The small, square "picture elements" that scans consist of. A pixel is all one color; when it is arranged with many others, an image is formed. (See "Resolution.")

PPI  Pixels per inch. A scanning term used to express the resolution of a scanned image; the number of pixels in a linear inch.

Prepress vendor  In this document, the term refers to a professional organization that operates high resolution scanning equipment, edits client provided digital mechanicals, merges the scans with the files, applies trapping and imposition and outputs plate ready film.

Printer spread  A graphic arts term that refers to two non-consecutively numbered pages of a booklet that are printed side by side on the same sheet of paper in the press (e.g. page 16 is paired with page 1 and page 2 is paired with page 15). During bindery, the printer spreads are assembled into a booklet.

Profiles  A file used by color management software which profiles the color reproduction characteristics of a particular scanner, monitor, printer or proofing system or printing press.

Reader spread  A graphic arts term that refers to two consecutively numbered pages of a booklet that appear side-by-side to the reader. In page layout software, reader spreads appear in what the software calls Facing Pages view.

Resolution  An expression used in scanning to refer to the number of pixels per linear inch (see "PPI"). The term is also used to refer to laser printers and imagesetters to express the number of laser spots per inch (see "DPI").

RIP  Raster image processor. The part of a Postscript laser printer or imagesetter that interprets information sent to it by the desktop computer (in the Postscript language.) After interpreting the Postscript data, the rip instructs the laser beam how to image the page.

Silhouetting  An image editing term that refers to the elimination of a background of an image so that, when put on a page, the image appears to float. Silhouetting can include a clipping path that allows the image to abut page layout elements such as tints and rules. Without a clipping path, a silhouetted image has white areas around its edge that are opaque and will knockout other page layout elements.

TIFF  Tagged image file format. A pixel-based graphics file format used for scans of line-art or photographs.

Trapping  A prepress term referring to the addition of a slight overlap where two colors touch. This overlap compensates for the natural misregister that occurs during a press run. Without trap, misregister could allow gaps to occur between colors and the paper color would show through. (Sometimes called "chokes and spreads.")

Tone compression  An image editing term referring to setting the highlight and shadow dot percentages to values specified by your commercial printer.  

Tone curve  An image editing and scanning term that refers to a tool for color correction, density and contrast adjustment. It allows the user to increase or decrease density of an image and if desired restrict this adjustment to a particular tone range (highlight, mid-tone or shadow) or to an individual process color.

White point  A scanning term that describes the assigning of pure white to the lightest area of a photograph. This causes the other tonal areas to shift so that contrast is maximized. (See "Black point.")