Pre-Press Terms and Definitions

Additive color: A color model associated with the RGB (red, green, blue) method of representing color. Equal amounts of the primaries will combine to produce the perception of white light. This is normally used in video systems/monitors.

Adobe Illustrator™: A software package for designing and illustrating. Some features include: a complete set of drawing tools, on-screen drawing and EPS-file formatting.

Aliasing: The stair-stepped (jagged) appearance in printed diagonal lines.

Anti-aliasing: A technique that smoothes the printed appearance of stair-stepped (jagged) lines. One method is to fill the edges of the line with varying shades of color (or gray). This method averages the brightness values of the edges.

Application: A computer software program that performs specific functions such as page layout, word processing, accounting, drawing and spreadsheet formation.

ASCII (American standard code for information interchange) (pronounced as-kee): ASCII is a computer code used to transfer numbers and text data between computers that run different software applications.

Banding: In digital printing, this term refers to patterns on a print caused by insufficient color or gray-scale ranges within the output device's image processor, or insufficient information contained within the original scan. Banding is most noticeable in printed areas that fade from light to dark.

Binary: A system based on the numbers 0 and 1 as on-off switches. There is no middle ground; electrical signals are represented by electrical current being positive or negative, on or off. All computer data is based on the binary system.

Bitmap: Generally, a bitmap is associated with graphics objects. The bits are a direct representation of the picture image. In a monochrome system, one bit in the bitmap represents one pixel on screen. With color (or gray-scale) systems, several bitmaps in the bitmap represent one pixel or group of pixels.

CMS (color-management system): The process of using device calibration and profiling, software-based color correction, and other utility applications to obtain predictable, quality-printed output. The output must remain within the limitations of the different devices that make up a digital-production system.

CMYK (cyan, magenta, yellow and black): The four colors in the four-color process. The primary additive colors, red, blue and green, when added together, produce white light. When overlapped, red and blue form magenta, green and red form yellow, and green and blue form cyan. These resulting colors are subtractive and when added together, they produce a dark brown. In order to create an accurate photographic reproduction, the color black must be added.

Color correction: The process of simulating the colors or original shade by using color-management software. Often, an inkjet printer serves as the CMYK output device. This process is important because spot colors cannot be acceptably reproduced with the CMYK color model without making adjustments.

Color gamut: The tonal range of colors that can be reproduced by a digital device.

Color measurement: The scientific determination of color. It uses specialized measuring machines to compare colors numerically. There is a CIE worldwide standard that helps the industry compare and match colors.

Color model: Also referred to as color space. A color model is a geometric or mathematical representation of visible colors. Well-known color models include, CMYK, RGB and HLS (hue, lightness, saturation).

Color profile: Also called device profile. This term refers to the relationship between the color models of the system devices.

Compression: The process of removing irrelevant information and reducing unneeded space from a file in order to make the file smaller.

Continuous tone: Like original photographs, drawings or paintings, continuous-tone images contain real gradients of grays or colors.

Default: An automatic decision that is made by computer software and hardware programs. The decision will automatically be carried out unless the user changes the default settings.

Densitometer: An instrument that measures transmitted or reflected light by indicating the percentage of a given area that is covered by halftone dots. This instrument is used to ensure consistency between films, proofs and printed pieces.

Desktop: In Mac and Windows, desktop simulates the top of the user's desk; the simulated environment appears on the computer monitor being used. The user's virtual desktop is organized through the tiling, cascading or overlaying of Windows.

DIC (device-independent color): The goal of DIC is to provide an independent, universal standard against which color spaces of all devices in a system can be referenced.

Digital camera: A lensed camera that uses a digital sensor for the film. Images are recorded on a disk and can be immediately output on a computer.

Digital color printing: To use multiple printheads that place specified colors of inks in predetermined places. The results are similar to photographs, but are often larger. In fact, some are billboard size.

Digital color-printing software: The computer programs that create digital color printing. The process uses mathematical algorithms to enlarge and print an image. Also, this software often includes add-on features such as color-calibration software, various pattern selections or a print-instruction screen. (See also, RIP.)

Digital imaging/digital printing: Digital imaging refers to the routines that take place before the output methods occur. These routines include: scanning, photo manipulation, color correction and RIPing. Digital printing, on the other hand, refers to a variety of computer-controlled output methods: inkjet, computer-airbrush, thermal-transfer and electrostatic printers and copiers.

Dithering: A graphics display or printing process that uses a combination of dots or textures to simulate an original image or an output device. The purpose is to create the impression of a continuous-tone gray-scale or color image.

Dot gain: A term that refers to the "weight gain" of halftone dots. During the printing process, the half-tone dots increase in size. Because this is an inherent part of the printing process, the effect of increased dot size should be anticipated ahead of time.

DPI (dots per inch): A measurement of linear resolution for a printer or scanner. For example, a resolution of 300 dpi means that there are 300 dots across and 300 dots down. A higher number of dots creates a finer resolution.

EPS (encapsulated postscript): A file type that allows the carrying of different information between software programs.

Error diffusion: In actuality, error diffusion is a random dot-placement strategy (or dithering method), spreading out the inherent failing until it is indistinguishable to the naked eye.

Ethernet: A commonly used computer network for the movement of PostScript files from one computer to another.

File format: A file format is indicated by a period followed by a three- or four-letter suffix, for example, .PDF the suffix indicates what type of file it is: a document, spreadsheet, drawing, Internet web page, etc. By knowing the properties of the various types of file formats, users can determine which files to open and read, which to import into other files and which offer the best options for scanning.

Front end: Front end refers to all the hardware and software &emdash; the scanner and computer workstation up to, but not including, the output device.

Gradation: The transition between colors or shades. Gradation occurs by mixing percentages of dominant and secondary color and then altering those colors to bring about a change.

Hexachrome: A color-matching system that allows for the combination of six colors in order to create a larger gamut of reproducible color.

Hue: A specific shade or tint of a given color. Hue is the measurement of the wavelength of light.

Inkjet printer: A type of printer that sprays tiny streams of quick-drying ink onto the paper. An inkjet printer produces high-quality printing like that of a laser printer.

Internet: A worldwide telephone hook-up between participating computers.

Interpolation: Interpolation is the process of injecting additional dots to digitally enlarge the original.

LPI (lines per inch): A traditional halftone screen measurement that refers to the number of lines of dots per inch.

Media: Another term for substrate. Common inkjet printers generally require media that have special topcoats to achieve proper adhesion and proper drying characteristics.

Network: A group of computers interconnected by hardware and software.

Overlaminate: A protective clear film that extends an image's outdoor life and enhances its visual quality.

Pixel: The smallest unit of data in a digital image. Together, the small discrete elements constitute an image that can be seen on a monitor or printed on a substrate. A pixel's code contains information relating to color, tone and placement within the larger image.

PostScript®: An Adobe programming language that enables text and graphic images to be output from different devices with consistent and predictable results.

PPI (pixels per inch): A measurement of resolution. A pixel is a unit of data that should not be confused with dpi (dots per inch) or lpi (lines per inch). If there are more pixels per inch, the image will be sharper.

Proprietary: Materials or software designed for use with one specific machine.

Reboot: The process of turning a computer system or printer off and then back on again, to reload the software.

RGB (red, green, blue): RGB is an additive color model used in color monitors, conventional photo film and paper to create full color.

RIP (raster image processing): A process using mathematical algorithms to enlarge and print an image. Also, this software often includes "add-on" features, such as color-calibration software, various pattern selections, tools or a print-instruction screen.

Scan-and-print: To produce "instant" posters, banners or other wide-format output, this type of inkjet system scales, interpolates and diffuses bitmapped images captured by a scanner. The purpose is to reduce the turnaround time and complexity in producing short-term display graphics.

Scanner: A hardware peripheral that illuminates, reads and then converts original text, artwork or film into digital data. Types of scanners include: flatbed or drum, and color or black-and-white.

Software: Computer programs that are necessary for all computer operations.

Spectrophotometer: Overall, an instrument that measures the spectral wavelength of color. Also, this instrument calibrates output devices or monitors, and measures dot gain and color density.

Spot colors: These colors are printed as solid areas and used when fewer than four colors are needed or when the four-color process (CMYK) is unable to accurately reproduce a PMS color.

Stochastic: An alternative to traditional halftone dots, this random-placement dot strategy is used to render enlarged images on large-format printing devices. Stochastic dots are uniformly sized "microdots," and their placement and frequency vary with the tone of the image.

Substrate: Ultimately, the material that receives the printed image. Sometimes, this term is called "media."

Subtractive color: Reflective color. The term refers to the CMYK color space used by conventional and digital printing devices to produce full-color printing. (See also, CMYK.)

UV inks: Inks that contain pigments or other methods to resist UV fade from direct sunlight and other UV light sources.

UV resistance: The resistance to fading under direct sunlight and other UV light sources.

Vector: An image plotted by lines on an X-Y axis. This image is different from a bitmap, which is composed of dots.

Virtual: Having the "appearance" of existence as opposed to actual reality, i.e. 3-D form.