Printing ABC

Printing ABC with technical terms of the printing industry

In the printing ABC on this page you will find many interesting technical terms on the subject of printing – sorted alphabetically with short explanations. Have fun looking…

Binding

Binding is the process of assembling individual pages and then joining them together, e.g. by means of adhesive or wire binding.

Bleed

The bleed describes the marginal area of a printed product that is included in the design but is later omitted due to trimming. If design elements (texts, images) are to be placed right up to the edge and appear as such, the designer must place the motifs beyond the format limit of the product (2-3 mm). The bleed area ensures that unsightly flashes are avoided and that printing specifications are met.

Blind embossing

A special printing process in which an engraving and, as a counterform, a die create an embossing in the paper under high pressure. Raised motifs are called raised embossing, deepened motifs deep embossing. With multi-level embossing, different levels can be combined. The high school is relief embossing with three-dimensional gradients.

Chlorine-free papers

Paper made from pulp that has been bleached without elemental chlorine or chlorine compounds. Oxygen and hydrogen peroxide are often used instead.

CIELab

Colour space for the representation of colour in a three-dimensional matrix. This is particularly suitable for measuring small colour distances and was standardised by the Comission Internationale d’Eclairage (CIE). L stands for brightness (luminance), a for the red-green value, b for the yellow-blue value.

CMYK

Offset printing presses work with the opaque, subtractive primary colours which, when printed on top of each other, produce black. These are green-blue, yellow, purple and black – i.e. cyan, magenta, yellow and black.

Coated paper

Paper used in high-quality printing because its smooth surface does not absorb ink like blotting paper.
Coated papers have a coating to improve surface smoothness, gloss, whiteness and printability. It consists of natural pigments, binders and various auxiliaries.

Collating

The placing of folded printed sheets (layers) of a book or a brochure one behind the other to form a book block in print finishing.

Colour depth

The colour depth refers to the number of bits with which the colour information of a single pixel is encoded. The more bits per pixel, the more differentiated and finer the image result.

Colour separation

Before printing multicolour products, the colour information must be separated. An image is separated into its basic colours by separating the CMYK colour channels. Each individual colour channel output (paper or film) would be a colour separation. Only when all four separations are printed together does the colour image result.

Colours

As a rule, printing is done in 4c Euroscale (cyan – magenta – yellow – black).
Of course, special colours (HKS or Pantone) are also possible. However, not in RGB!

Computer-to-Plate (CtP)

Without detours via films, the printing plate is exposed directly from the computer via a RIP.

Corporate design

Corporate design encompasses all the attributes through which a company can communicate with its environment. An image is defined and transported into the environment. The entire appearance of a company is determined. Colours and fonts for printed products and other advertising media, as well as the message that is to emanate from it, or the choice of architecture, office equipment, presentation in the media (advertisements), the brand of company cars, the colours of work clothes, etc., are all defined in it.

Data compression

Reduction of the volume of digital data, which can thus be transported faster and require less storage capacity. There are methods in which data is lost and lossless calculations.

Density

Density refers, on the one hand, to the application of ink in offset printing, where the combination of the four process colours results in a corresponding thickness of the ink layer. On the other hand, density describes the degree of blackness when exposing paper or film materials.

Digitisation

Conversion of analogue information into digital data.

DIN formats

In 1922, paper formats were defined in DIN 476. All formats have an aspect ratio of the side length to the diagonal length of a square. DIN A0 corresponds to the approximate area of one square metre, exactly 0.999949 square metres.
Below are the format specifications for DIN A0 to DIN A 8 in width x height:
DIN A0 = 841 mm x1189 mm
DIN A1 = 594 mm x 841 mm
DIN A2 = 420 mm x 594 mm
DIN A3 = 297 mm x 420 mm
DIN A4 = 210 mm x 297 mm
DIN A5 = 148 mm x 210 mm
DIN A6 = 105 mm x 148 mm
DIN A7 = 74 mm x 105 mm
DIN A8 = 52 mm x 74 mm

DPI

Dots Per Inch (pixels per inch) refers to the screen ruling. In metric units, a 30 screen is approx. 76 dpi, a 50 screen approx. 127 dpi, etc.

Euroscale

Standardised colour table that defines the printing sequence, saturation and colour tone for the printing colours yellow, magenta, cyan and black (CMYK) used in four-colour printing.

Foil stamping (digital)

Digital foil stamping or hot foil stamping gives printed matter a noble partial metallic effect. The digital process is inexpensive and flexible because no further tools such as embossing dies are necessary. The respective motif is simply printed onto the paper with a hot stamping foil in digital printing. 4c digital printing can thus be combined with silver, gold or coloured metallic foils.

Grooves

Technical term for the mechanical pressing in of fold breaks before folding, which is intended to prevent the paper or ink from breaking open.

Images

If necessary, include in .psd or .tiff format. Note compression for .jpeg format.

Imposition

Put pages in a certain order for printing, e.g. 4-page invitation card.

Ink density

The optical density of ink areas on a substrate is an important criterion in quality control and standardisation of offset printing. With a reflected light densitometer or an ink density measuring system, the brightness or saturation of colour tones can be compared on the basis of logarithmic values.

JPEG

The Joint Photographic Expert Group compression is used to break down and compress images. Loss of quality in texture and colour must be taken into account.

Knocking away

Physical drying, whereby the binding agents or solvents of the printing inks penetrate the paper and resin components with pigments remain on the surface and harden.

Leave out

Non-covering part of an area where the paper remains unprinted during printing.
E.g. Yellow is printed on Cyan – it would no longer be Yellow. Thus, in cyan form, omissions must be made in yellow areas.

Logos

In ai, eps or tiff format.
For ai and eps format, include any fonts used or convert fonts to paths.
For jpeg format, observe compression.

lpi

The screen ruling for printing is often given in lines per inch. The larger the screen ruling, the smaller the dots, the higher the resolution and quality.

Moiré

The overlapping of several halftone patterns creates an iridescent, undesirable optical effect. Moirés occur, for example, when scanning printed, i.e. already rasterised originals.

Newsprint

Paper containing a lot of wood or waste paper, machine-smooth, with a basis weight of 40 to 57 g/sqm.

Offset printing

Offset printing is a process for reproducing monochrome and multicolour products from the four primary colours cyan, magenta, yellow and black. In this flat printing process, the substrate is not printed directly from the printing plate, but indirectly by means of a blanket cylinder.

Opacity

Opacity of the paper.

Overprinting

The term overprinting is used in the printing industry to describe the overprinting of transparent (translucent) colours. By printing the process colours together, new colour tones are created. In pre-press, overprinting also refers to the assignment of properties before colour separation. If, for example, there is a black font on a yellow font (background), the text is assigned the overprinting property so that yellow is not omitted at the point where the text is located during separation. A cut-out would lead to flashes in case of register inaccuracies, which cannot happen by overprinting the yellow colour.

Paper running direction

Predominant fibre direction in the paper; it depends on the running direction in the paper machine.

Paths

Create fonts in paths: Safe way to avoid difficulties of fonts, but text correction is no longer possible.

PDF

(Abbreviation for Portable Document Format): File format that Adobe has established as a standard. It is used for the platform- and programme-independent exchange of data of any pages with the help of Acrobat. PDF files can now be created directly from many application programs. PDF files can be viewed and printed with Acrobat Reader.

Perfect binding

Binding method in which the contents are milled off a few millimetres at the binding and joined together with hot glue. The contents are then “hooked” into the cover at the spine.

Perforate

Punches in the material to allow a part to be separated.

Pick

Lifting, tearing or pulling out of paper components, more or less tightly bound paper fibres, parts of the filler in uncoated papers or parts of the coating or impurities occurs when too much mechanical force is exerted when the ink is transferred to the paper.

PostScript

The page description language PostScript developed by Adobe represents characters and graphic elements in such a way that they can be output in the highest possible resolution of the printer or imagesetter, independent of size. PostScript graphics saved in PostScript mode and intended for placement in other layout programs have the extension .EPS (Encapsulated PostScript).

Preflighting

Simulation of the output process on the computer. Instead of a hardware RIP in a printer or imagesetter, a software RIP takes over the processing of the output file. Possible problems can thus be detected on the screen without consuming output material.

Print sheet

The print sheet is a substrate on which several individual pages (4, 8, 16, 32 or 64 copies) are printed together on the front and, if necessary, on the reverse side. The size of the print sheet is limited by the technical requirements of the printing press.

Printouts

Should be supplied with each exposure, both as a complete printout and as colour separations.

Proof

Before a print product goes into mass production, a proof should be created. This single print gives a colour-binding preliminary impression of how the later product will look, e.g. produced in offset printing.

Raster

Many DTP printers (such as laser printers or film imagesetters for offset printing) can only print solid black and no halftones (grey). An image or typeface that contains grey tones must therefore be rasterised. Lighter image values are represented by smaller pixels, darker image values by larger pixels. The pixels are black with white areas in between. By spacing the dots equally, a pattern is created. If the dots are small enough, the human eye no longer perceives the pattern and so a grey colour impression is created. Each image pixel is made up of many, essentially smaller exposure pixels.

Register / registration marks / bleed marks

Fine crosshairs for fitting and control when joining several colours. Fine lines outside the final format to mark the trim.

Resolution

Line image at least 800 dpi.
Raster image at least 300 dpi.
(Raster value x 2.54 x 2 = dpi; e.g. it is to be printed in a 60 raster 60 x 2.54 x 2 = 304.8 dpi).
The number of picture elements (image dots or also print dots) per unit of length or area results in the resolution. Mostly they are expressed on the length unit inch (2.54 cm) in lpi, ppi, dpi. The number of pixels per unit of length determines the level of detail.

Retouching

Retouching is when image areas or individual pixels in a bitmap are changed manually by electronic means in image processing.

RGB

Abbreviation for red, green, blue. The three colours of light together produce white light and are the primary colours of additive colour mixing, the principle of which is used by scanners and colour monitors, among others.
A zero density of red, green and blue leads to black. If all three colours have the same value (between 0 – 255), the result is black, a value-dependent grey tone or white.

RIP

Raster Image Processor. Here, data from page description languages such as PostScript are converted into a pixel pattern, which is then transferred to an appropriate output medium.

Screen ruling

Screen ruling describes the number of halftone dots on a specified distance. It can be given in lines per cm (l/cm) or lines per inch (lpi). The higher the screen ruling, the better the detail reproduction of an image, as more pixels are available for reproduction.

Sleeking print

As sleeking printing is based on digital printing, it is particularly suitable for short runs and variable data. With this digital hot foil stamping, fonts, logos or surfaces are simply fixed to the substrate with the desired metallic Sleeking foil.

Son of a bitch

Traditional term for a single-line sentence rest at the beginning of a new paragraph or column.

Tiff

The tagged image file format Tiff has developed into a leading format for digital image processing. A Tiff file can be passed on to almost any exposure studio, as the Tiff format is virtually a standard format. In addition to the colour modes greyscale, RGB, CMYK or CieLab, Tiff also accepts images with mask channels and paths. Almost always the lossless LZW compression method is offered as an option when saving.

Tonal values

In the transition between the absolute colours black and white, grey tones are created, which are also called tonal values. A 50% grey tone has half the intensity value of the colour black.

Trapping

In multicolour printing, when two colour areas are next to each other, they are allowed to overlap slightly so that no "flashes" can occur in the event of slight register inaccuracies in the print. The overlap is set so that the lighter colour overlaps the darker colour. This slight increase in the "size of the object" is thus perceived least by the viewer.

TrueType

Scalable vector fonts are called TrueType fonts. Unlike bitmap fonts, the line does not consist of dots, but of a connecting line between defined dots. These fonts can be scaled and changed without loss because the connecting line is always recalculated after a change in shape.

Type 1 fonts

Fonts that store their description in the form of PostScript commands. The format developed by Adobe will probably no longer be supported from 2023 and will be replaced by TrueType or Open Type fonts.

Uncoated paper

Papers without coating; therefore also called uncoated papers.

Watermark

The watermark is an essential feature of European paper and was considered a protected business mark early on – from the 14th century onwards. It can take on all conceivable forms and characters and in its diversity can therefore serve as a historical identifier.