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The Heidelberg website glossary explains, in alphabetical order, a multitude of terms relevant to printing, as well as some terms used in Heidelberg's product catalogue.

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Sans serif

One of a number of typefaces without serifs.

Satellite principle

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.

SC

See "HWC".

Scanner

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”.

Screen

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.

Screen angle

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.

Screen dot

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.

Screen dot distribution

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).

Screen element

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.

Screen model

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.

Screen proof

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.

Screen resolution

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

Screen ruling

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.

Secondary pulp

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

See-through register

A print element on banknotes used to protect against counterfeiting. Parts of a character or symbol are printed on both sides of the note and only appear as a complete character when the note is held up to light.

Selective binding

The personalized production of bound print products from a selection of components. Selective binding can be used to produce different versions of catalogs tailored to specific customer groups or when various advertising motifs are required for different issues of a magazine.

Semi- fine

Paper stock with a mechanical wood pulp content of more than five percent. The term is usually reserved for uncoated papers, as coated stock is usually referred to as “slightly mechanical”.

Senefelder, Alois (1771-1834)

The inventor of lithography and stone printing. In 1796, Senefelder discovered that by using a greasy substance to write on polished Solnhofen limestone and then lightly etching it with an acidic gum Arabic solution, ink would only adhere to the areas which had been written on. In 1818, Senefelder published his “Vollständiges Lehrbuch der Steindruckerei” (The Complete Textbook of Stone Printing), in which he outlined how the discovery came about.

Separation

The decomposition of the color data of an image into separate colors (in accordance with the CMYK color model) for the individual passes of the four-color printing procedure; also denotes means the conversion of RGB colors in to CMYK colors.

Separation algorithm

One of the formulas or procedures performed for color space transformation.

Serif

A small stroke at the end of the lines of a letter. This design feature is typical of so-called Roman faces. Serifs cater to the perception mechanism of the human eye and thus make type faces easier to read.

Serigraphy

Silk screen printing.

Set form

A text layout in which the length of the lines varies according to the placement of optional images or graphic elements.

SGML (standardized feneralized mark-up language)

A standardized language (ISO 8879) used to depict structured texts. SGML is very versatile, but is difficult to use due to its size. Of greater significance is XML, a reduced version of SGML designed specifically for exchanging structured data in the Internet.

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