1. general information
These technical guidelines are intended to simplify communication between the customer and the printing works. The purpose of the guidelines is to create a print product at a predictable level of quality in a printing process based on a division of labor through clear interface definitions. On the one hand, the guidelines define the requirements for data provided that are necessary to achieve optimum printing results. The guidelines also define the quality that can typically be achieved in printing and finishing, and the tolerances that can be applied in production.
1.1 Complexity of print jobs
Depending on their complexity, print jobs can be divided into the following levels of complexity:
- Few complex print jobs: These are single- or two-colour jobs with simple finishing such as cutting or burglary folding
- Medium-complex print jobs: These are jobs printed in four or more colours or jobs with more complex finishing, such as multi-fold folding or brochure production
- Highly complex orders: These are four- or multicolour printed jobs with high quality standards (e.g. art prints or productions with particularly complex finishing (art book productions, partial UV varnishing).
2. data delivery
The following requirements apply to the transfer of provided data:
2.1 Data format
2.2 Colour management and colour profiles
If the data is supplied as RGB, all elements must be stored with unique colour profiles to enable standardised colour management If the data is supplied in CMYK, the current standard colour profiles for the paper used should be used in consultation with the print shop. For RGB data, colour profiles must be stored in any case. The currently valid standard profiles are shown in Media Standard Print, page 12f.
If you want images or colored areas in the document to reach the edge of the paper, these page elements should be placed in the document so that they extend about 3 mm beyond the normal bleed margin. This bleed allowance is necessary to compensate for possible deviations during folding or trimming. If the bleed is missing, the paper color may become visible in the final production run and the print may not extend beyond the edge.
2.4 Image resolution
Too low image resolution leads to unsightly and pixelated results. As a rule of thumb for a sufficient image resolution is recommended:
- For periodic screens: 2 pixels per screen width (e.g. 120 pixels/cm at a screen frequency of 60 lines/cm)
- For non-periodic screens: 1 pixel per five times the diameter of the smallest screen dot (e.g. 100 pixels/cm for a 20fünffacher dot)
Note: Typically, an image resolution of 300 ppi produces a good result in print. Images with a higher resolution do not need to be converted to a lower resolution. (ppi: pixel per inch, measure for the resolution of images).
The print file should contain only those pages that are actually printed. The print file should contain all pages in the correct order, including the unprinted pages (blank pages).
3. correction PDF, proof print and proof
A correction PDF or a test print is used for a general check of the print product, whether for typesetting errors, completeness, page order and presentation or positioning of all elements, but not for the assessment of the colour reproduction. A proof largely anticipates the desired print result and serves primarily to assess the colour reproduction.
3.1 Monitor proof
If a proof is carried out on the monitor, the colours on the screen may differ from those printed. Only a calibrated monitor under standardized conditions allows a color-accurate representation. For the exact requirements for a monitor proof, see A.3.2 Media Standard Print
3.2 Digital colour proof printing
For a largely binding result of the test pressure, it must meet the requirements of ISO 12647-7:2016 and be viewed under standard lighting conditions. For the exact requirements for a digital proof, see A.3.2 Media Standard Print
4. quality of print
A good print quality is achieved by maintaining set values for solid inking, dot gain and grey balance/toner spread within a defined tolerance range. Different paper grades produce different results, so these must be taken into account in the design. The print quality can be checked by printing control strips during the production run.
4.1 Tolerances in four-colour printing
The tone value increases must correspond to the applicable values of the corresponding part of the ISO 12647 series of standards within the tolerances specified there for production printing. The solid colouring is based on the colour-consistent test prints or press proofs. If these are not available, the colour values specified in the relevant part of the ISO 12647 series of standards or the relevant colouring standard shall be used. For evaluation, the Print Media Standard, Chapter B.6 - Print run.
5. paper weight and format
5.1 Tolerances in paper weight
The paper weight is given as grammage per square meter (g/m2). The fluctuation range of the basis weight can be up to ±5%. This tolerance must also be applied to the paper thickness of the printed product: Depending on the nominal thickness, this also varies by ±5% Example: if the grammage of a paper is specified as 100 g/m2 , the actual grammage can vary between 95 g/m2 and 105 g/m2 .
5.2 Tolerances in final format
The final format of the printed product may differ from the specified format by up to 1 mm.
5.3 Format and colour differences due to surface finishing
With cellophaning, lamination or UV varnishing, the size of the sheet can also change depending on the direction of travel, paper weight and paper quality. Possible difference: ±1 mm. Such transparent coatings can also lead to slight colour shifts with certain colour shades.
6. tolerances of further processing
In industrial print finishing, printed paper is converted into finished products in several work processes. This manufacturing process is usually carried out mechanically (cutting, folding, stitching, etc.) and therefore cannot be carried out without differences. In the technical process, the tolerances of the individual work steps accumulate from assembly and printing to further processing.
6.1 Cutting tolerances
Cutting deviations are possible due to different paper properties, as the paper must be pressed together before the cutting process.
Possible tolerances: up to ±0.1 mm per cut
6.2 Folding tolerances
The displacement of material in the folding process can lead to different positional and type area deviations in the end product, especially with cross-folded products.
- Burglar fold: up to ±0.5 mm
- Two-fold fold: up to ± 0,7 mm
- Triple fold: up to ± 0,8 mm,
- Fourfold fold: up to ± 0,9 mm
6.3 Tolerances in the production of brochures and books
The dimensional accuracy is determined on the finished block. Possible tolerances: up to ±0.7 mm
For staple-stitched booklets produced by saddle stitching, the possible format tolerance is up to ± 1 mm
6.4 Mounting tolerances for brochures and books
When the core is hung in the cover or book jacket, many factors influence the alignment of the core in advance. Possible tolerances: up to ± 0.7 mm
6.5 Creasing, perforating, punching
Scoring is the weakening of the paper sheet by means of a score line. The result is a linear depression, which appears as a raised area on the opposite side. Creasing is recommended before folding thicker paper sheets (from 200 g/m2). Perforating is understood as punching a line of holes or lines into a material. Punching is defined as cutting with self-contained geometric blank shapes (e.g. circular, oval, polygonal, etc.). Possible tolerances for these operations: up to ±1 mm
6.6 Embossing and hot foil stamping
Embossing is the stamping of writing or other motifs onto the material (paper). This can be done without color as blind embossing or with color as color embossing.
Hot foil stamping is a finishing technique using foils whose coating is pressed onto the material (paper) by pressure and heat.
Possible dimensional tolerances for embossing and hot foil stamping: up to ± 1 mm. Depending on the material and embossing motif, slight markings on the back of the hot foil stamping motif cannot be ruled out. These are process-related, as metal is melted under heat and pressure, compressing the paper.