A compression format and the corresponding file extension used primarily with Apple computers.

One of a number of typefaces without serifs.

The principle by which offset printing works. Several complete units, including plate cylinder, blanket, inking unit and damping unit, are arranged around a central impression cylinder. In this way, all the colors are printed in a single, wet-on-wet process.

See "HWC".

A device for capturing image data which works by optically reading or “scanning” the original. Light-sensitive sensors convert information regarding image brightness and colors into electrical values. The two major types of scanners are the drum and the flatbed. See also “drum scanner” and “flatbed scanner”.

In image reproduction terminology, an area made up of small geometric forms of either regular or random arrangement, for example round, square or other shaped dots and lines. The screen is used to convert contone images into a black/white or full-color representation suitable for printing. This is done by varying either the size or the frequency of the elements to reflect the brightness of the image.

With regular screens the angle of the screen from the vertical. When single colors are used, the screen is generally positioned diagonally (45 or 135 degrees). In multicolor printing, different screen angles should be used for different colors in order to prevent overlay effects (moiré). DIN 16547 prescribes angles of 0, 15, 75 and 45 degrees for the colors yellow, magenta, cyan and black.

An element of an image based on a complex mathematical structure, according to which an area is defined and a gray value is determined. The more exact the rendering of black is, the more accurate the gray values must be in the use of inks, toners or other chemicals.

The manner in which the individual dots are arranged within a defined area of a screen. There are two screening techniques, amplitude modulation (AM) and frequency modulation (FM).

A part or fragment of an image as seen on a computer monitor. The smallest screen element is the dot, and several dots make up a pixel.

Model generated by geometric modeling or computer simulation techniques and used for an optical comparison of different screening systems. The process enables manufacturers of CtP imagesetters to develop new optimized screening systems.

Proof used for layout and color information control, and to check the screen structures of a print. Screen proofs are intended to eliminate moiré, rosette and other undesired effects. As the printing data contain no screen information before screening of the images in the RIP (raster image processor), screening must be performed before a screen proof is printed.

The number of pixels displayed on a screen; at present, high-resolution screens are capable of displaying 1024 x 768 pixels and more.

The number of dots per unit length that a screen contains. Common specifications are l/cm (lines per cm) and lpi (lines per inch). “60 screen” means 60 l/cm and corresponds to approximately 150 lpi.

Pulp consisting of raw materials reclaimed from wastepaper. The term can refer to chemical pulp, wood pulp or a mixture of the two.