The term achromatic composition is a term used in process engineering for the electronic reproduction of color sets.

Areas of an image that become black or gray anyway are not built up by the portions of the colored basic colors (CMY) (as generated by the color build-up), but by black printing ink.

Figure 1: Comparison of Chromatic build-up versus Achromatic build-up - original image

Figure 2: Comparison of Chromatic build-up versus Achromatic build-up structure - Achromatic build-up

Figure 3: Comparison of Chromatic build-up versus Achromatic build-up - Chromatic build-up

Additive color is a method to create color by mixing a number of different light colors, with shades of red, green, and blue being the most common primary colors used in the additive color system.

Adobe Systems is one of the world's largest software manufacturers and focuses on products for the media and creative industries.

Groundbreaking developments are Postscript and its "successor" PDF.

The current versions of the graphics and multimedia programs are summarised in the Adobe Creative Cloud.

Spot Colors have an alternate Color Space that is used for conversion to the target Color Space if the Spot Color cannot be directly separated in the output. The following Color Spaces can be stored as an alternate Color Space for spot colors:

• CMYK - was stored as the default value in the early days of print production.
• RGB - rarely used in practice
• Lab - is used by default in practice nowadays, as this ensures that a conversion to any target color space will result in the smallest possible ∆E value.

It has been possible for several versions to generate Approval Reports in the Workflow and download them locally. Subsequently, these reports had to be sent manually by e-mail to the responsible employees.

With version 1.11.1, an Approval Portal is available as a cloud service that communicates with the local Workflow. Approval Projects can be generated in the Workflow and transferred directly to the Approval Portal. The responsible person receives an e-mail with a link to the Approval Dashboard, where they can accept or reject the respective approvals without having to register. The decision of the responsible person is automatically transferred to the Workflow with a corresponding comment.

An Approval Project can consist of one or more approvals (Approval Reports). Approval Projects can be created locally in the Workflow and managed in the Approval Dashboard in the Workflow. However, the content of an Approval Project can also be transferred to an Approval Portal, which allows for the possibility of online approval by the end customer.

Approval Projects were first provided with version 1.17.2. In earlier versions, individual Print Items were made available to the end customer via an Approval Report by e-mail or online via the Approval Dashboard.

See Page Geometry

Definition of an Article

A monochrome raster image format. Each dot (pixel) is either filled (black, on, 1) or not filled (white, off, 0), there are no gray tones (halftones, grayscales).

The name Bitmap comes from the 1:1 mapping of each pixel to a dot/pixel on the screen.

Bleed is printing that goes beyond the edge of where the sheet will be trimmed. Bleed marks belong to the larger category of Print Marks. They represent a special form of a cutting mark.

See Page Geometry

Blend methods may be applied to entire objects or to their individual parts as well as entire object groups. Behind each blend method lies a defined blend function. The blending takes place between the foreground color (CS = source color) and the background color (Cb = background color). The result is the result color (Cr). The variables cr , cb and cs describe the corresponding values for the colors Cr , Cb and Cs additively.

For more information on Blend Methods, see the article Blend Methods.

Browser Cache is a buffer memory of the web browser, in which retrieved resources (e.g. texts or images) are stored on the user's computer (locally) as a copy. If a resource is needed again later, it can be retrieved from the local cache more quickly than if it had to be reloaded from the server via the Internet.

https://en.wikipedia.org/wiki/Web_cache

A Calender is a series of hard pressure rollers used to finish or smooth a sheet of material such as paper, textiles, or plastics.

CCITT – short for Comité Consultatif International Télégraphique et Téléphonique – is a lossless compression algorithm defined by the ITU. The best-known methods are CCITT Group 3 (technical designation = CCITT T.4) and CCITT Group 4 (technical designation = CCITT T.6). Both encodings have been developed specifically for the compression of 1-bit image data, not for color and grayscale images and also not for general data. While Group 3 coding was specially designed for analogue data transmission via communication lines (telephony/fax), Group 4 is already optimized for the coding of digital data for transmission.

CCITT contains three different algorithms that have been specially optimized for typewritten and handwritten documents. These are:

• CCITT Group 3 one-dimensional: This type of coding is quite similar to that of RLE. Here too, "runs" are recognized and their length is coded with the corresponding value. The difference to RLE is that the "Runs" are not self-defined, but the coding of the "runs" is taken from fixed value tables in which typical "Runs" of black and white pixels are stored. These tables are based on statistical surveys (non-adaptive procedure) on the frequency of average "runs" of black and white pixels and are part of the CCITT T.4 specification. As with RLE, each scan line is considered separately in one-dimensional coding.
• CCITT Group 3 two-dimensional: While one-dimensional coding only takes into account the horizontal "Runs", two-dimensional coding also takes into account the vertical sequences. Only the differences to the previous line are saved or transferred. This means that the coding of a scan line is influenced by the previous line, which in turn can lead to transmission errors when transmitting via telecommunication channels. Two-dimensional coding thus achieves a significantly higher degree of compression by storing the difference values than can ever be achieved by the optimized storage of "Runs".
• CCITT Group 4 two-dimensional: In practice, CCITT Group 4 coding has already completely replaced two-dimensional Group 3 coding. Group 4 coding is essentially based on exactly two-dimensional Group 3 coding. It differs only in two important points. First of all, the K-factor has been set to infinity. This factor describes how many scan lines are encoded vertically on top of each other. Furthermore, since Group 4 was developed for data encoding on hard disks, parity bits can be neglected as no transmission errors are to be expected. Group 4 coding is more complex and requires a great deal of computer power, which is, however, always available in today's systems.

Summary: CCITT Group 4 encoding provides the best algorithm for compressing 1-bit image data. This type of coding leads to almost no reduction in halftone images.

Technically speaking, CCITT is a lossless, symmetrical and non-adaptive compression method. In PDF, CCITT is addressed via the CCITTFax-Decode-Filter . Parameterization of the filter is provided. It is not often possible to set these in the graphical user interface of graphic, layout and PDF editors.

Chroma is the C component of the LCH color space.

Chroma represents how far out from the center of the color space (radially) a color lies. The farther out the more saturated the color. The "colorfulness" of a sample judged proportional to the brightness of a white reference sample in the same medium and under the same illumination.

see Google Chrome Webbrowser

The term Chromatic has it's roots from color separations.

All color tones are built up from Process colors (CMY). K is only available as skeleton black (short black). Undercolor Removal (UCR) is only effective in the darker portions of the image.

Figure: Comparison of chromatic vs. achromatic versions of an image.

Figure: Comparison of the chromatic structure versus the achromatic structure.

Figure: Comparison of the chromatic structure versus the achromatic structure

CMYK is based on subtractive color, a linear inversion of the RGB model. Colors are created by mixing cyan, magenta, and yellow. The color appearance is created by reflecting light and the absence of certain wavelength ranges of the originally emitted light.

Figure: Schematic representation of how filters remove secondary colors from light, leaving only the primary colors.

When light hits substrates, a part of this light and the therein-contained wavelengths are absorbed by the substrate. Thus, the signal reaching the eye is spectrally altered. If a surface absorbs the red part of the spectrum, only green and blue parts are reflected. The mixture of green and blue is cyan, so the eye perceives a cyan-colored surface.

A substrate that filters out all areas of the spectrum appears as black. By using the CMYK process, colors are created by printing the subtractive primary colors on top of each other – unlike monitors, which emit colored light,  However, the subtractive colors also depend on the lighting.

Figure: Schematic representation of the CMYK subtractive color model.

The primary colors in subtractive color mixing are cyan, magenta, and yellow. The secondary colors in the subtractive color model are red, green, and blue. The secondary colors are created by mixing two primary colors and omitting the third primary color. The complementary colors to the primary colors of the subtractive color model CMYK are:

• Cyan > Red
• Magenta > Green
• Yellow > Blue

Also known as "bit depth". Specifies the number of bits used for each pixel to store the color or brightness value of that pixel.

Method/algorithm for Color Conversion.

After profiling, a default Color Policy must be assigned for each Substrate so that the Substrate can be applied in the Workflow to Articles, Orders, or Production Jobs.

Doing the Color Setup for a substrate means determining its calibration - the printer prints on the substrate in a linearly defined state - and the Color Setup - the description of the printer's color gamut on the substrate.

A Color Space is a specific organization of colors. In combination with physical device profiling, it allows for reproducible representations of color, in both analog and digital representations. In our case this includes the following Color Spaces:

• Black and White – also known as "bitmap" or "dash". Each pixel is either black (or 0 or "off") and white (or 1 or "on"), there are no nuances between the two colors.
• Grayscale – colloquially referred to as a black-and-white image. Between black and white there are graded grey tones (= half tones). See also Color Depth
• RGB – The RGB color model is an additive color model in which red, green and blue light are added together in various ways to reproduce a broad array of colors.
• CMYK – is a subtractive color model, used in color printing, and is also used to describe the printing process itself.
• LAB – the absolute (mathematical) color space with which the light perceived by the human eye can be imaged.

Color Spaces can vary greatly in a PDF file.

1. A utility found on Mac operating systems that allows users to view and manipulate the details of ICC profiles installed on the computer.
2. The underlying structure within Mac operating systems that coordinates the color between devices.

A Contract Proof is a color-binding and legally binding proof according to ISO 12647-7. The contract proof is currently the highest proof standard with the tightest tolerances and is therefore considered a "contract", i.e. it is the contract between the proof producer and the print shop.

An example for checking and issuing a printing system is the Validation Print Creation certificate by Fogra. Companies that are certified by Fogra for Validation Print Creation are likely to carry the FograCert logo. By entering the certification number on the Fogra website, it is easy to check the standard of the Proof and whether the certification is correct and valid.

As a normal user, you can start the Command Prompt as an Administrator as follows:

Before Windows 10:

In the search window of the (Windows) Start menu, type cmd, right-click Command Prompt in the search results, and then select Run as Administrator.

Windows 10 and later:

Right-click the (Windows) Start menu (Windows icon) and select Command Prompt (Administrator).

Bleed Marks [1] are small strokes that are found on the untrimmed printed sheet and mark the final format of the printed matter. They give the final processor - bookbinder or operator on the cutting plotter - an indication of where the final product should be trimmed and separated from the bleed.

A cutting mark, also known as a cutting mark, cutting mark or format mark, belongs to the print marks.

Figure 1: A schematic representation of Crop Marks, this example also includes Bleed Marks as well.

Another type of Printing Mark is the Crop Mark [2]. On the untrimmed printed sheet, it marks the area that an operator on the cutting plotter is to use to trim the final product plus the bleed.

EPS stands for Encapsulated PostScript and is a specific variant of a PostScript file. In contrast to PostScript, EPS can also be imported into graphics and Office applications and integrated into the other PostScript commands during output. This file type is a standard format for the exchange of graphics between different system platforms. Due to the advent of PDF, EPS files are rarely used nowadays.

The EPS file type is intended to solve the problem of data exchange in the area of graphics across systems. This file format can therefore be characterized by the following features:

• PostScript exchange format - EPS is a cross-platform exchange format for PostScript. EPS consistently uses DSC comments.
• Contains the PostScript Imaging Model - EPS files can also contain text, vector and pixel information. If the file is opened in Adobe Photoshop, all elements are rendered.
• Limitation to one page - EPS files are limited to one page. However, this means that certain PostScript commands for page definition may not be used.
• Preview - An EPS file optionally contains a preview of the image. As some operating systems are not able to render EPS directly, this preview is necessary, which is then used in the output if no PostScript interpreter is available in the printer.
• Fonts can be embedded - it is not absolutely necessary for the fonts used to be embedded in an EPS file. However, prepress programs are able to do this.
• BoundingBox - an EPS file must contain a description of the geometric extent of the page objects in the form of the BoundingBox. This enables the imported program to access the section of the objects to be placed.
• Color Spaces - an EPS file can process the color spaces bitmap, grayscale, RGB and CMYK. The processing of spot colors is technically possible, but is usually mapped using special formats.

There are well over 120 standard Fixups to choose from in the Workflow. You can quickly find out whether a suitable Fixup is already available for the problem you are looking for by searching for keywords.

Deflate, which was implemented with PDF 1.2, is a compression method that mainly combines two algorithms. On the one hand, a dictionary-based algorithm equivalent to LZ77 (LZW) is used to effectively encode repetitive sequences, and on the other hand, a Huffman code is used as an entropy encoder. While LZW is based on a patent from Unisys, Flate works with the public domain zlib/deflate-compression method, thus offering a solution free of charge.

Difference to LZW : A significant difference between LZW and Flate is immediately apparent to the user when compressing non-repeating patterns. While LZW increases the file size in this case to at least 1.125 times, or even up to 1.5 times, an enlargement by Flate is only possible up to 1.003 times, but a maximum of 11 bytes larger than the original.

Summary: Everything that has been said about LZW can be applied to Flate. However, if you have the choice between the two algorithms, always opt for the Flate algorithm. More effective compression should be reason enough to use it.

Technically speaking, Flate is one of the lossless, asymmetric compression methods, whereby compression is performed logically. In PDF, Flate compression is addressed via the FlateDecoce Filter. As with LZW, it is generally possible to parameterize the filter, but this is not provided for in the user interface of graphic, layout and PDF editors.

Flipping Horizontally, Flipping Vertically and Rotating are technical terms for the turning/rotating possibilities of a printed sheet, regardless of whether the process is carried out with one or two Print Items.

When the sheet is flipped horizontally, the sheet moves in the direction(s) described below in the diagram..

Figure: A visual representation of the horizontal flipping process.

Flipping Horizontally, Flipping Vertically and Rotating are technical terms for the turning/rotating possibilities of a printed sheet, regardless of whether the process is carried out with one or two Print Items.

When the sheet is flipped vertically, the sheet moves in the direction(s) described below in the diagram..

Figure: A visual representation of the vertical flipping process.

FOGRA is a German-based Research Institute for the graphic arts. They are very actively involved in maintaining several ISO standards (ISO TC 130) concerning color management and printing. Based on ISO standards, they developed a system of certifications for print providers. proofing systems and proof providers known as FOGRAcert. www.fogra.org

Typical examples of Fonts are e.g: Helvetica, Rotis etc. A complete Font can consist of several Fonts weights - Regular, Italic, Bold or Bold Italic - or a font can be part of a Font family - Rotis Semi Sans, Rotis Serif and so forth.

The term Font embedding refers to the process of embedding the graphic description of the characters in the print file so that they are available for display on the monitor or for output to the printer (during rendering). Font embedding can be done in two ways.

Describes the size of a gamut of a substrate - printer and ink/toner combination.

This is our recommended browser for Workflow operation.

Download: https://www.google.com/chrome/

Hotfolders offer several advantages when large amounts of Print files need to be processed automatically. The user can control whether the files are added to a Production Job or ripped immediately after checking-in.

A measurement of the amount of light coming from a light source. Illuminance is measured in footcandles (or Lux).

When files are saved incrementally, this means that the changes that have been made in the document are appended to the end of the file structure.

Figure: Comparison of the file structure of a PDF file linear (left) and incremental (right)

The advantage of incremental saving is that the saving process can be mapped quickly. The disadvantage is that the document size increases continuously, which can very quickly lead to sizes of up to 10 GB in the case of very large PDF files.

Typically a block which contains information about the Order or Customer in a readable form (human or machine) and is printed on the print sheet or near the Print Item.

Inprints can be selected in the "Send to Printer" dialog.

Ink Cost Calculations: Some features and enhancements have been implemented in relation to ink cost calculation in the Workflow. These are:

• Calculation for multiple Print Items – Ink cost calculations and ink cost reports can now be calculated and created for multiple print items or Articles. This function is available under Articles > Articles, Orders > Print Items and within an Order by selecting multiple print items.
• Manual calculation – Improvements have also been made to the manual ink cost calculation in the »Statistics« tab of a print item or Article.
• Automatic calculation – At various points in the Workflow, an additional option has been implemented that allows ink cost calculations to be performed automatically.

Creating an Imposition involves placing single print items or a combination of print items on a substrate or sheet. The arragement of these items is then optimised to minimize waste as well as create sheets that are layedout in a way that streamlines the finishing process if necessary.

JFIF is short for JPEG Interchange Format and is the actual format designation for a JPEG file. The term JPEG describes the algorithm for compressing within a JFIF file.

The acronym JPEG is short for Joint Photographic Expert Group. In 1982 ISO established the Photographic Experts Group with the goal of developing methods for efficiently transmitting text and still images.

JPEG is the most broadly know compression algorithm of images for the Web as well as for prepress processes. The algorithm is a lossy procedure that was mainly developed for compressing half-tone images (color depth of min. 8 bit per channel) and not for compressing black-white or induced images or general data. In comparison to other compression procedure JPEG is not an individual compression method but a library of methods that's suitable to the users' needs. JPEG offers a standard for data compression but isn't a file format.

The compression of JPEG is controllable across multiple JPEG quality levels. Theoretically and according to the specification there's the possibility to carry out a lossless compression. In practice this procedure is rarely conducted due to missing parametrization in grafic or PDF editing programs. Rather the adjustable five quality levels (the number is dependent on the used application) are used for the different Workflows. The quality levels can either be of maximal quality (=low compression rate) to low quality (=high compression). For the use in print it can be said that with a maximal quality a compression rate of 1:4 and with the lowest quality a compression rate of 1:25 is possible.

The demands on JPEG were enormous. The format was expected to be suitable for diverse areas of application, the compression should have been adjustable independently from the color depth and size or resolution of the image by a factor. Furthermore, JPEG was expected to be integrated easily into Software and Hardware

In order to meet the requirements, JPEG was designed in such a way that a multi-stage process is necessary for compression. These coding stages are:

1. Conversion to the YCrCb color space: In order to come closer to the goal of generating optimum quality, the output data must be converted into a form that allows a distinction to be made between relevant and irrelevant content. For this purpose, the image is converted into a color space in which the brightness information can be stored independently of the color values. The color space of JPEG is YCrCb, where the Y-axis represents the luminance and the color values (color difference components) are encoded in the other axes.
   The reason for this conversion is that the differences in brightness can be better distinguished by the human eye than the differences in color.
2. Subsampling: As the human eye perceives information about brightness better than change in color information, the brightness signal Y is saved in full resolution. The reduction of the resolution takes place in color axis by subsampling, therein two to four pixel of each color component are summarized in an averaging process to one pixel. The brightness is fully maintained. This explains why grayscale images - which lack color information - cannot be compressed so well by JPEG. Depending on the quality level, the color information is switched to the same level, which leads to a flattening of the details.
3. Discrete Cosine Transformation: In a further step, each color component created after subsampling is encoded using the DCT compression method. Each component is broken down into 8 x 8 pixel blocks and mathematically transferred to a frequency space using cosine transformation. The result is an output matrix that has the same size as the input matrix. Therefore, there is no data reduction. In the output matrix, the first element describes the DC component, while the remaining 63 components describe the AC component of the discrete-time input signal.
4. Quantization - weighting of the contents: The individual matrix elements are weighted using predefined or self-generated quantization tables and divided by constant values. Depending on which quantization is used, image information is lost. Higher frequency components (= darker image areas) are weighted more heavily than lower frequency components, which is why darker image areas tend to fall by the wayside during quantization. The choice of JPEG compression (maximum, high, medium, low, low) therefore results in different quantization being used. As with DCT, the original data volume is retained after quantization. Images that have already been compressed with JPEG should therefore not be saved again as JPEG, as re-encoding will result in a loss of image information.
5. Lossless compression: After quantization, the DC (first element of the 8 x 8 matrix) and AC coefficients (the remaining 63 coefficients of the matrix) must be placed in a sequential order. The AC and DC coefficients are coded using different tables (VLI and VLC coding). Finally, the coefficient chain is compressed without loss using Huffman coding. Frequently occurring symbol sequences are assigned short code words (removal of redundant information).

Summary: JPEG is and remains the most common compression method for storing halftone information for all color depths from 8-bit grayscale, 24-bit RGB to 32-bit images. Compressing 1-bit images is possible, but is negligible in terms of quality limitations. Only at medium and high compression rates do block artifacts appear, which significantly impair the image quality.

Technically speaking, JPEG is a lossy and asymmetric compression method. In PDF, JPEG is addressed via the DCTDecode-Filter . Parameterization of the filter is provided.

JPEG2000 is characterized by better mathematical processes compared to JPEG. The new standard was introduced in summer 2000 under the name JPEG2000 Image Coding System. The file extension of JPEG2000 is, quite unexpectedly, jpf.

The goals that were to be achieved by JPEG were already ambitious at the time. With JPEG2000, the proven format was to meet further requirements:

• Higher compression than is possible with JPEG.
• A multiple increase in quality - especially in the low bit depth range (high frequency components) - should be achieved.
• A reduction in the formation of block artifacts should be achieved.
• A loss-free method for processing black and white images must be guaranteed.
• JPEG2000 should not only be excellently suited for images, but also for encoding computer graphics or entire files with text and image data.
• Improved transferability by integrating a higher error tolerance with regard to transfer errors.
• The possibility of progressive transmission, i.e. splitting into different resolution levels, must be integrated.

The invention of 2000 as JPEG2000 can be described by the following characteristics:

• The basis of JPEG2000 coding is the wavelet algorithm. The result of the wavelet transformation are wavelet coefficients that describe the image in different resolutions.
• JPEG2000 can compress both lossless and lossy halftone and black-and-white images. Lossless compression is the basis for a compression method that should not only be used for pixel images.
• The different "layers" in a JPEG2000 file describe the different quality levels of an image. This means that for a higher quality image, only the quality required for the process is used rather than the entire image. This could also be used in pre-press, as proof printing usually does not require such high-resolution information as exposure. The important thing here is that both output forms work with the same file.
• It is also interesting that so-called regions of interest (ROI) can be defined within an image - these must be mapped via masks - which can be used to achieve partially higher or lower compression qualities.
• In contrast to JPEG, transparencies and alpha channels can be saved with JPEG2000. While the transparencies are retained when reopened in Adobe Photoshop, the alpha channels (masks) are missing.
• Up to 256 color channels with a color depth of 1 bit to 16 bits per color channel are supported. This means that CMYK information can also be saved in addition to RGB images.
• With JPEG, indexed image stocks are still limited to a color table of 256 colors; with JPEG2000, this color table can be extended to 1024 colors.
• JPEG2000 is a separate file format. The sRGB color space is activated as standard within the format. However, ICC color profiles and therefore also eciRGB color profiles or output profiles such as ISOCoated_v2 can be integrated into the file.
• JPEG2000 also supports metadata. This means that date entries, copyright notices, author, keywords, title designations and freely definable meta information as well as all EXIF information can be stored in the file.
• The internal structure of the format in boxes (Signature Box, Header Box, Contiguous Codestream Box) means that the required content can be accessed more quickly without having to decompress beforehand.

Summary: The advantages of being able to accommodate a high compression rate with less visible loss of quality in a file are so tempting in practice that no manufacturer should be able to avoid JPEG2000. JPEG2000 has found its way into PDF with the PDF 1.5 specification. JPEG2000 is no magician, but on average a reduction of 25% to 50% in file size is possible compared to JPEG. Regardless of which color space, which color depth, which resolution and whether paths, alpha channels and color profiles need to be embedded, JPEG2000 would be the format that comes closest to an "egg-laying wool-milk sow" in the range of file formats.

Technically speaking, JPEG2000 is one of the lossless or lossy and asymmetric compression methods. Internally, a distinction is made between JP2 and JPX.

In PDF, JPEG2000 is addressed via the JPXDecode-Filter. This can only be applied to image XObjects. Parameterization of the filter is provided. The option of setting these in the graphic interface of graphic, layout and PDF editors is not available to the full extent and is therefore not usable.

JPEG2000 compressed PDF files are generally smaller and of better quality than JPEG files. Rendering this content can result in a longer rendering time, which is why the compression algorithm is not implemented in many programs.

In contrast to the device-dependent colour spaces RGB or CMYK, the CIELab colour space describes colour objectively, i.e. the colour values are thus clearly and unmistakably defined. The Lab color space separates the brightness (L) from the two color coordinates a- (red-green) and b-axis (yellow-blue). In addition, this color space includes all color impressions perceptible by the human eye, which are represented in it with approximately equal visual distance. An equal distance between two points results in a nearly equal sensation for the color difference of these two colors everywhere in this color space.

Figure 1: Schematic display of the Lab Color Space

Light inks have a lighter concentration. It is usually only a dilution of the respective base colour. They are mainly used to achieve pastel shades on large areas in order to partially solve the problem of visible graininess caused by dithering.

The process of measuring and correcting for a device's inability to see or reproduce a straight line of tones from black to white.

The process of Linearization is most commonly used to ensure an image setter reproduces the same halftone dot values predicted by the imaging software.

The work of Abraham Lempel and Lempel Ziv formed the basis for a large number of coding methods, which are generally referred to as LZ methods. Based on the original methods LZ77 and LZ78, a wide variety of derivatives have been developed over the course of time. The method used in PDF is LZW.

Functioning of LZW: LZW is based on LZ78 and was modified by Terry A. Welch in 1984. LZW is probably the most widely used lossless algorithm, which is used in TIFF, GIF, PDF and also PostScript (from level 2) to save data more compactly.

Like RLE, LZW can also be applied to any form of data, regardless of whether it is text or image data. Compression and decompression take place at the same speed (= symmetrical compression), as the dictionary is created at runtime during both encoding and decoding.

LZW is based on a dictionary. First of all, the algorithm constructs a data dictionary with a maximum of 256 entries of all uncompressed information. Then, in contrast to RLE, the data stream is not searched for "runs" of identical information values, but for patterns (substrings) in the data stream. From the pattern, encodings are calculated that represent the compressed data. If an already known pattern occurs again in the image data, the existing coding is used and the pattern is written into the compressed data. The word "will" can be made up of the known part "w" and the as yet unknown part "ill", resulting in a new pattern. The data dictionary can contain up to 2¹² entries.

A special feature of LZW is that the lexicon does not have to be saved. This further improves the compression rate. Elements that are stored in the lexicon - for example: the first 128 characters of the ASCII code - are stored as 1-byte values and are therefore available for compression and can be restored from them.

Difference calculation: In order to compress data better, the method of difference calculation (= differencing) is often used. With this type of calculation, it is not the value (information content) of the next pixel that is saved, but only the difference to the original pixel. In halftone images in particular, directly adjacent pixels differ only slightly, which means that differential calculation results in data reduction, which can of course also be restored completely correctly. For 1 to 8-bit data, the differences between the pixel values are calculated directly; for RGB data, only the differences in the individual channels R, G, B are calculated and used for compression. This limits the compression rate somewhat.

The Predictor Key can be used to tell the decoder whether normal LZW compression (Key=0) or extended differential compression should take place. The predictor key for TIFF is always 2. Predictor keys above 10 are used for the successor format to GIF (PNG).

Summary: LZW is just as efficient as RLE for 1-bit data. The compression rates for 8- to 24-bit images are usually more efficient with LZW, especially if noise suppression has taken place in the images. However, more effective lossless data compression can be achieved with "flat" color images such as cartoons or technical plans. With this type of image in particular, sharp edges and pure surfaces must be retained.

Technically speaking, LZW is one of the lossless, symmetrical compression methods, whereby compression is performed logically. In PDF, LZW is addressed via the LZWDecode-Filter. It is generally possible to parameterize the filter, but this is not usually provided for in the user interface of graphic, layout and PDF editors.

You can set up multiple Measurement Devices with the appropriate configurations. However, only one Measurement Device may be connected via USB per Workstation/Server Configuration. However, Measurement Devices which are connected via a unique IP address can be connected and used simultaneously.

See Page Geometry

The phenomenon by which two materials that match under one circumstance appear different to different viewers or under different lighting. Metameric mismatch occurs when tristimulus values are the same but spectral characteristics are not.

Using Nesting mode, Print Items are arranged in a way which saves material (Substrate) depending on the size of the impose sheet and the number as well as the quantity of the Print Items to be printed. Nesting typically reduces waste and optimizes the layout of Print Items to make the finishing process easier when post processing.

In printing, 2-up, 3-up, or more generally N-up refers to a page layout strategy in which multiple pre-rendered pages are Imposed onto a single page; achieved by reduction in size, possible rotations, and subsequent arrangement in a grid pattern. The primary purpose of N-up printing is to reduce the number of pages that a printed work would otherwise require without having to re-edit, index, or flow the layout of the individual pages of an existing work.

Optical brighteners are additives that paper manufacturers put into paper in order to help a paper look "whiter." They are also called optical brightening agents (OBA), fluorescent whitening agents (FWA) or sometimes "artificial whiteners."

In order to make paper appear brighter, it is common for most paper manufacturers to add certain chemicals to the paper which can take invisible ultraviolet light and cause it to re-emit in the blue spectrum - or fluoresce - at a point that is just barely within our ability to see. While our eyes see this as a brighter, blue-ish white - a light measuring instrument will only see this as a different form of blue. For this reason, printer profiles made with paper using a lot of optical brighteners can produce images that have a yellow tint to them. The profile is trying to correct for what it sees as too much blue in the paper.

Virtually every paper that has a noticeable bright white appearance has some amount of optical brightener. Examples of paper with OBA in it are common office bond paper, Epson Premium Matte, Luster, Glossy, etc., and most every other brand of commercial inkjet paper. The chemical agents in paper causing this fluorescence will lose their effectiveness over time so that over the course of several years, the apparent brightness of the paper will decrease. It won't be "glowing" with the artificial white that it did when new. This is part of the reason why some people choose to print with "natural" papers.

The OBA value can be calculated as follows:

• Measurement of the paper with M1
• Measurement of the paper with M2
• Difference of the b-value of M2-M1

The OBA values can be interpreted as follows:

• OBA value = 0: no optical brightener
• OBA value = 0-4: Little optical brightener
• OBA value = 4-6: Medium optical brightener
• OBA value > 6: A lot of optical brighteners

The term OCR is short for Optical Character Recognition. OCR is a technology that enables automatic text recognition of letters, words, and numbers in image files. The letters, words, or numbers in the file are captured and converted into editable and searchable text.

The technology behind OCR is based on the principle of pattern recognition. Letters, numbers, and punctuation marks are compared with a database and thus recognized as text or text characters and combined into a word or an entire sentence. In the past, automatic text recognition used its custom fonts, which were quickly and reliably identified by the OCR reader. Modern OCR methods use algorithms and artificial intelligence (AI) for this task.

Modern OCR processes can be divided into five steps:

1. Layout analysis – To make individual characters visible at all, the file must first be converted into a black-and-white image. This optimally highlights the text against its background and allows for identifying layout elements such as headlines, paragraphs, or tables.
2. Segmentation – The next step is to distinguish the individual letters from the graphical elements of the file. This involves identifying each text passage line by line.
3. Character recognition – Pattern recognition is used at this point. Each previously found character is now compared with the database. Features such as height, width, or the general structure of the character help in this process. This is how all characters are converted into letters, words, and numbers.
4. Post-processing – Newer OCR methods also perform a kind of autocorrection. Here, artificial intelligence is used to improve the accuracy of character recognition.
5. Encoding – In the last step, the result is transferred to a new file format so that it can be processed or further edited by the user.

PDF does not have a layer construct, as is the case in graphics applications such as Adobe InDesign, Adobe Illustrator or Adobe Photoshop. Layers are referred to as Optional Content Groups (OCG's) in PDF. As the name suggests, OCGs in PDF were initially designed to make content optionally visible or invisible.  The following table explains the differences between the two:

Table 1: Layers vs. OCG's

Optimized saving is also known as linear storage. Thereby, all incremental attachments are incorporated into the file structure which results into the file being saved in the smallest possible file size.

Figure 1: Comparison of the file structure of a PDF file incremental (left) and linear (right)

The advantage of optimized saving is therefore the smallest possible file size of the document. The disadvantage of optimized saving is the processing time as the process of saving the file takes a little longer than usually.

If a Production Job has been created, the Output Configuration can be changed according to the requirements of the customer or other desired output results. This is necessary for example if the print must be suddenly produced on another machine, or on another material. The output configuration can be changed using the Output Configuration tab.

The output intent describes the final target device with which the color is reproduced in the PDF document. The Working Color Space is overwritten while being displayed and printed. The output condition is described with an ICC profile. The output intent contains an embedded device profile that defines the Color Space of the target device, for example PSO Coated V3.

Overlap – Describes the additional area needed for gluing individual tiles.

Overprinting is basically the object-related setting of overprinting parts. These overprinting parts "mix" with each other. For example, when an object that is colored with pure cyan (100/0/0/0) and another object that is colored with pure yellow (0/0/100/0) are set to overprint, they become green. Overprinting elements that are marked with OPM 0 or OPM 1 can be displayed by the overprint preview of various graphics applications - such as Acrobat Pro, InDesign CC, Illustrator CC or the PDF Editor.

Figure: Left: pure cyan, magenta and yellow that are set to overprint; Right: The same objects but set to Knockout

The two states OPM 0 (also known as standard overprint mode) and OPM 1 (also known as Illustrator overprint mode) should not go unmentioned, especially in connection with overprints:

• OPM 0 - this mode means that 0% of the foreground color in a channel overwrites the background color.
• OPM 1 - this mode means that 1% of the foreground color in a channel overwrites the background color.

This means: when two CMYK elements (defined in DeviceCMYK) are superimposed, the upper object is set to Overprint and OPM is also set to 1, the color of the upper element is always used in printing. This is the case unless a color channel has 0 % - in this case the internal value is used. Only various overprint combinations with images are excluded from this rule.

Figure: Left: file without overprint preview; Right: file with activated overprint preview

Explanation regarding the above figure:

All three "K" in the background are a light blue area with the color values 50/0/0/0/0 and a black outline with the color values 0/0/0/0/100. The three "K" in the foreground are set to Illustrator overprint mode (OPM 1) and differ marginally in the Fill Color.

• The left "K" has a 100% magenta area, all other color channels are set to 0% (0/100/0/0).  
• For the middle "K", 1% cyan was added to the area (1/100/0/0).
• For the right-hand "K", 1% cyan and 1% black have been added to the area (1/100/0/1).

Table: The result of the calculation of overprinting objects with OPM 1.

The page geometry frames of a PDF file are the boxes available in the PDF. There are five different page geometry frames:

TrimBox [1] – The final format frame, also called TrimBox, represents the final size of the printed and cut document. A document designed for printing requires a final format frame. The size of the final format frame must be smaller than or equal to the bleed and media frames.

BleedBox [2] – The bleed frame, also called the BleedBox, is an extended area around the final format frame that trims all page content in the output. A document that has been designed to drop (beyond the edge) also requires a bleed frame, which in practice is between 1 and 10 mm, depending on its use. The bleed frame should always be larger than the final format and smaller than the media frame. Print marks such as registration marks, crop marks or color bars should always be outside the bleed area.

MediaBox [3] – The media frame, also called MediaBox, represents the physical size of the media and corresponds to the selected paper format used when printing to a PostScript or PDF file. The media frame thus contains all the objects on a document page that appear on the page or protrude beyond the edge of the page size.

ArtBox [4] – The object frame, also called ArtBox, forms a frame drawn around all printable objects and defines the content to be placed on the page as intended by the document creator. The final format frame and the object frame usually have the same size, but this is forbidden in connection with PDF/X files - here only either object or final format frames may be present.

CropBox [5] – Mask frames, also called CropBox, are created by trimming the page with suitable tools. The mask frame is used by default both for display in PDF display programs and for placing PDF files in layout programs.

PDF stands for Portable Document Format. In 1991, Adobe co-founder John Warnock launched the Camelot project. The aim was to develop a file format that would allow documents to be captured from any program, sent as an electronic file and displayed and printed independently of the end device. In 1992, Camelot evolved into PDF, which has become the de facto standard in the graphics industry over the decades. The origin of PDF actually lies in the display list, an intermediate state of the RIP process of a PostScript file that is stored in a document. PDF is therefore a pure "object-based file format" to which no calculations or procedures need to be applied in order to enable output to screen or paper.

The following four properties speak in favor of using PDF in prepress:

• Cross-platform visualization - the content of a file can be displayed on all operating systems. The PDF format can save all content that can be written with PostScript. In addition to Adobe Reader, current operating systems have integrated PDF viewers that can also be used for display.
• Font embedding - an important point for a cross-platform display is that fonts can be reproduced accurately. The used fonts can be embedded directly in a PDF file.
• Low data volume - storage space can be reduced by encoding page content much more compactly and simply storing identical objects/images.
• Random access to objects, pages and file structure - PDF allows random access to objects and pages of a document. The individual components are separate objects in the file and can also be used multiple times on different pages. It does not matter whether it is text, vector graphics or images.

PDF works with the Adobe Imaging Model, i.e. the graphics model of PostScript. A PDF can consist of three page objects:

• Vector or path objects - a sequence of individual or connected points, lines and curves that are mapped in the PDF file in the form of path construction operators.
• Text objects - consist of one or more glyphs that are mapped as path objects in a separate data structure, the fonts. Like path objects, text objects can also consist of an outline and a fill.
• Image objects - rectangular areas consisting of individual pixel values that are stored by their unique position in the rectangle and the color values.

With each new Acrobat version, the associated PDF specification has also been changed. Extensions have been made to the format which open up new possibilities for certain areas of PDF application. Here is an overview of Acrobats' version designation and the corresponding PDF version:

Table 1: Overview of the PDF versions

Plate Templates – With version 1.11.0, the user can now save user defined layouts for printing plates as a template, which are required for conventional printing processes, in order to use this as a basis for an imposition and to transfer the entire imposition with the Plate configuration as a PDF to a platesetter.

See Contact

Under Print Marks, all markings on a printout that are applied outside the print image for further processing. These Marks include:

1. Color Control Strips [1] – These are usually applied only to the top and/or bottom edge of a printed sheet.
2. Registration Marks [2] – Typically contain one set per sheet. In digital printing Registration Marks are no longer so important.
3. Bleed Marks [3] – These are applied per page/motif.
4. Crop Marks [4] – These are attached per page/motif
5. Production Order Name [5] – These are applied per page/motif
6. Page Number [6] – These are attached per page/motif
7. Issue Date and Time [7] – These are applied per page/motif

Illustration: A visual overview of common Print Marks

Print data is stored in the Workflow, together with job-related customer information, production and delivery data, and all information describing the actual output, such as substrate and color strategy, in so-called Production Jobs.

An Order can include one or more designs, it can also be "empty", i.e. the sales department can create an Order in the Workflow before the customer delivers the print data. These could be added to the Order later by an operator.

The final step in print production is usually to transfer the print data to the printer. This involves passing the document(s) or the Imposition to the integrated RIP with all the necessary rendering and color management parameters. The result of the RIP process is usually a device-dependent control instruction (job ticket) for the printer plus the required print data, which is then transferred to the printer via the network.

If a cutting device with a parameter set has also been selected in the Production Job, the cutting files for the print job are generated in the same process and also transmitted to the IP address stored for this purpose.

For the Workflow, the Production Job is initially completed after the transfer, which is why the status automatically changes to Sent to Printer. Whenthe connected printing system communicates with the Workflow, the status of the Production Job can still change automatically depending on the type of integration of the printing system.

In the printing industry, a Proof is a preliminary simulation of a print result to be used as a Template for the Production Run.

The aim of a Proof is to simulate what the subsequent print result will look like in order to detect possible errors at the earliest possible stage. In this way, errors are prevented from being discovered until after printing, thus avoiding complaints.

Proofs are usually output as a composite file on an inkjet printer that has more than 8 colors. In addition to the print data, a Proof must also bear a UGRA/Fogra Media Wedge in order to be color-compliant and legally binding. Thanks to the standardized Wedge, the printing company is thus able to check the Proof for correctness.

Using QR codes or any type of 2D codes is one of the everyday undertakings when creating machine-readable data carriers. However, QR codes are also used in some regions of the world as design objects for creating unique designs. The content to be transported in QR codes can be entered manually as well as specified in the form of a CSV file. QR codes are required for the following use cases:

• Lottery numbers – unique number for lotteries, tombolas, etc.
• Business cards – Storing structured content - e.g. address information - on business cards or conference cards.
• Posters/advertising materials – Packaging of URLs to provide quick access to further information about the product, a promotion, or an event.
• Identity Cards/Badges – create access permissions for trade shows, conferences, fitness centers, etc.

Registration Marks [1], also known as the register cross or register, is a graphic figure that can be used to monitor the accuracy of fit of the individual colours in the printing process. Usually this mark consists of a circle and a cross of thin lines, similar to a target cross. By precisely aligning the individual separations, "flashes" in the printed image can be avoided.

For the register mark to be printed on all separations (CMYK + Spot Colors), it must be marked with the Registration Mark Color.

Illustration: A visual representation of the positioning of Registration Marks on the printed image

A Registration Mark Color is a color definition that is printed at 100% in each separation. Thus, a surface which has been marked with this color has 400% total ink coverage in a CMYK print. With a CMYKcm-OVG print, the total ink coverage would already be 900%.

Technically, there is a color definition called "All" for the registration mark color in PDF and PostScript.

The Registration Mark Color should be used in design creation only for Registration Marks or Crop Marks and not for creating deep black vector areas or texts.

Method for converting different color spaces from one space to another.

Number of identical copies of a motif or a page of a motif.

In relation to a single printed sheet, this is the number of copies to be cut from this sheet.

RGB is one of the physical-technical color models that describe a color as a mixture of primary colors. As the human eye contains three types of color-sensitive cones, the triple theory was developed early. This theory has remained the basis of color television on monitors and color photography to this day.

The triple theory states that all visible colors are mixed together from exactly three primary colors. The condition for the primary color criterion is that none of the primary colors can be mixed from the other two.

Figure 1: Schematic depiction of the primary and secondary colors in the RGB color space

The additive color model RGB is based on the primary colors red, green and blue. If all primary colors are mixed, the color "white" is created. Where only two of the three colors are mixed, the so-called secondary color is created. In RGB, the secondary colors are Cyan, Magenta and Yellow.

Secondary colors are also referred to as the complementary color of the missing third primary color. The mixture of Green and Blue results in Cyan. Cyan is therefore the complementary color to the missing Red. This results in characteristic pairs of complementary colors:

• Red > Cyan
• Green > Magenta
• Blue > Yellow

A RIP - Raster Image Processor is a special software or a combination of hardware and software that converts data from a page description language such as PostScript, PDF or PCL into a pixel graphic (raster graphic), which is then usually output to a printer.

A RIP essentially implements two functions:

1. Rendering – conversion of vector graphics into pixel graphics (raster graphics) into a halftone image in a certain resolution
2. Screening – conversion of the halftone image into a pixel image consisting only of the existing print dots

The term Raster Image Processor is only used explicitly in prepress, where this component performs other tasks in addition to the functions mentioned above:

• Color management – Calculation of colors in the output color space
• Separations – create individual color separations for the printer
• Grid – Create a pixel grid, where pixels are either distributed or arranged at an angle.
• Trapping – create additional areas to avoid speed cameras at hard color edges

Run Length Encoding (RLE) is a very simple compression algorithm that is supported by many pixel file formats such as TIFF, BMP, PCX, Targa and, of course, PDF. In general, the method is suitable for all types of data, regardless of their information content. However, the degree of compression is strongly determined by the information content, which makes a thorough knowledge of the processes of this algorithm absolutely essential. Under unfavorable circumstances, it can happen that the result of the compression is a larger file than the original.

RLE is based on the reduction of the physical size of repetitive information (redundancies). The sequence of information with the same content is referred to as a Run. For coding, information is summarized in a Run Packet , which is usually coded with two bytes, whereby the first byte indicates the number of information in the "Run" (Run Count), the second byte the information value (Run Value). The Run Count can assume values from 0 to 255 or 1 to 256, whereby the value 0 is used in some procedures to separate the Runs. If the series contains more than 255 identical pieces of information, a new Run must be started and a new Run Packet created.

Classical procedure: The character string "aaaabbc" requires 7 bytes when uncompressed (if we assume one byte per character) and only 6 bytes after RLE coding "4a2b1c". From this representation, it can be explained that the type of compression also has limits. Long sequences (Runs) of the same information values lead to a high degree of compression; with constantly changing information, the effectiveness is reduced, which can even double the memory requirement for compressed images. The character string "abc" would be "1a1b1c" after compression, which would double the storage space from 3 bytes to 6 bytes.

Improved procedure: Various forms have been developed to prevent duplication from occurring:

• A counter is included in the Run Count, which indicates the number of uncoded data or indicates that repetitions occur in the sequence.
• Between the Run Packets, if more than three repetitions occur, control characters are introduced to separate the packets.

Summary:

RLE (Run Length Encoding) – ist eine einfache und schnelle Methode der Komprimierung – sie ist Grundlage für viele andere Verfahren. Die Effektivität ist jedoch stark vom Informationsgehalt der Datei abhängig. Ein Schwarz-Weiß-Bild eignet sich sehr gut für RLE, da darin viele Abfolgen gleicher Pixelwerte enthalten sind. Farbbilder hingegen, bei denen jeder Pixelwert einen anderen Wert haben kann, eignen sich nur sehr schlecht für diese Art der Codierung. Die einzige Ausnahme dabei sind Farbbilder, die im indi­zierten Farbraum vorliegen. RLE wird in den verschiedenen Programmen unterschiedlich bezeichnet, z. B. als Run Length oder Lauflänge.

Technisch gesehen zählt RLE zu den verlustfreien, symme­tri­schen Kompressionsmethoden, wobei die Kompression physi­ka­lisch erfolgt. In PDF wird diese Kompression durch den RunLengthDecode-Filter angesprochen. Eine Parametrierung des Algorithmus ist in den Grafik-, Layout und PDF-Editoren nicht vorgesehen.

The rotation factor is used to rotate the page by the set factor when opening a PDF file in a PDF viewer. However, the page is not actually rotated, but only displayed as such in the preview of the PDF viewer. The rotation factor is specified in degrees  0, 90, 180 or 270.

EAN and ISBN Barcodes can be created in required sizes. Previously a barcode could be created in any size and changed freely afterward. In ISO/IEC 15420, the sizes of EAN and ISBN barcodes are officially standardized in the form of SC Sizes. These specifications are often requested by customers in orders from the packaging and label industry.

Table 1: SC Barcode Sizes according to ISO/IEC 15420

SC 2 represents the standard size. Therefore, the dimensions 25.93mm [1] apply for the height and 37.29mm [2] apply for the width. According to the regulation, these values may be proportionally reduced to a maximum of 80% or enlarged up to 200%. So-called SC values reflect the standard value in different sizes. The text sizes to be used for human-readable information are also assigned to the SC size.

Figure: Size specification of SC 2 using the example of an EAN 13 barcode

In a digital printing system, a separation-maintaining color (additional color) is a color that is to be used as a Spot Color in the printout. Examples would be White, Varnish or Ferrari Red. Whilst White and Varnish must always be marked as maintaining separation, Ferrari Red could also be used as process colour. If the color is created as a process color, this color is taken into account as a gamma-expanding color in the color management; separation-preserving colors, on the other hand, are not color-calculated but are added as an additional color to the color management.

Another option has been implemented in the "Nesting" imposition mode for imposing or nesting Print Items with irregular shapes. The new Shape Nesting option makes it possible to generate an optimized variant of nesting by nesting irregular shapes inside each other.

The sheet is the area available for Imposing print items. The sheet is typically defined by the the width and height as well as the edge dimensions. Sheets typically are Imposed with a Motif to optimize the print process and reduce waste. Sheet Margins usually contain Inprints which are blocks of information usually related to the printing process and/or finishing instructions.

See Spot Color

Using Step & Repeat Mode, Print Items can be arranged in columns and rows on the imposition sheet according to specific rules. Step & Repeat Mode is mainly used for printing items that need to be cut using either a Die or in bulk stacks during the finishing process.

A Spot Color - also called Solid Color - is a printing color used in multicolor printing in addition to the Process Colors. In a digital printing output, Spot Colors are only used to define the Primer, White or Varnish separations. Classical Spot Colors such as PANTONE, HKS, RAL, etc. are transferred separately to the Target Color Space of the printing system via color management in digital printing. How well the Color Space of the Spot Color can be achieved depends on factors like ink used, number of process and gamut-extending colors used, the Substrate including its pretreatment, and the printing system itself.

In the Workflow, as well as partially in the PDF Editor, the following options are offered in connection with Spot Colors:

• Vectors with defined CMYK values can be converted into a Spot Color.
• Spot Colors can be transferred to the Target Color Space of the printing system.
• Spot Color Separations can be created depending on the overall color application.
• The linearity of Spot Color Separations can be modified.
• Spot Colors can be set to Overprint or Knockout.
• Spot Colors can be renamed, deleted, the alternative Color Space can be changed and its color values can be modified.
• Spot Colors can be separated from DeviceN Color Spaces
• Spot Color separations can be duplicated

The Fixup for these options can be found in the Print Data View in the Spot Colors settings area and in the Print Item Layer in the Data Preparation tab.

A factor on which the Spot Color is dependent.

It is clear from the name that Subsampling is not a time-consuming and therefore rather poor method for downsampling image data.

Functioning: In the short calculation, the value of the middle or bottom right pixel is used for the resulting larger pixel.

The example in Figure 1 illustrates the procedure for downsampling. A pattern with a resolution of 600 ppi is to be subsampled to 300 ppi and 200 ppi. When subsampling to 300 ppi, 2 x 2 pixels (4 pixels in total) are combined to form a larger pixel. The value of the larger pixel is the value of the bottom right pixel of the 2 x 2 matrix. However, if the image is scaled down to 200 ppi, 3 x 3 pixels (9 pixels in total) are combined to form a larger pixel. The value of the new pixel is the value of the middle pixel of the 3 x 3 matrix.

Figure 1: Schematic illustration of the cross-calculation from 600 to 200 and to 300 ppi

When upsampling (up-interpolating) images, pixels are added by repeating pixels.

A Substrate is used in a converting process such as printing or coating to generally describe the base material onto which, e.g. images, will be printed. Base materials may include:

• plastic films or foils
• release liner (for adhesive labels)
• textiles
• plastic containers
• any variety of paper (lightweight, heavyweight, coated, uncoated, paperboard, cardboard, etc.)
• parchment

A Subtractive Color model involves the mixing of a limited set of dyes, inks, paint pigments or natural colorants to create a wider range ofcolors, each the result of partially or completely subtracting (that is, absorbing) some wavelengths of light and not others. The color that a surface displays depends on which parts of the visible spectrum are not absorbed and therefore remain visible.

TeamViewer is proprietary computer software for remote control, desktop sharing, online meetings, web conferencing and file transfer between computers.

https://www.teamviewer.com/en/

Tiling mode allows you to split oversized print documents that exceed the width and height of a standard substrate into smaller pieces (Tiles) which includes additional areas for gluing each tile together.

See Page Geometry

In the printing industry, TAC - Total Average Coverage - is the sum of all superimposed color values. Depending on the Substrate used, the inks used (UV-, toner- or water-based) and the printing process, the total ink coverage must not exceed a certain percentage value, as this can no longer ensure dryness or the layer thickness becomes too thick, which can cause the ink to break off.

The word user unit basically refers to the adjustment of different units in scaling. In connection with images and graphics, the size of the image is changed. Depending on whether it is a pixel or vector graphic, scaling can have an impact on the quality of the image.

There are the following differences between pixel and vector graphics:

• If a pixel graphic is now enlarged, the pixels of the image are also enlarged. Larger pixels also make edges appear more stepped, creating the so-called sawtooth effect.
• Vector graphics can be scaled to any size. Graphics can be enlarged without any loss of quality.

When we talk about user unit in the context of a PDF, we talk about the factor - 1:2, 1:5 or 1:10 etc. - which is applied to the effective page size in the output of the print file in the RIP.

As background information, you should also know the following statements about the user unit:

• The page length of a PDF can be a maximum of 200 inches (5,080 mm). PDF files that are larger than this must therefore include a scaling factor.
• User unit is technical jargon (PDF terminology) and means page scaling factor.
• User units can only be embedded in PDF files from version 1.6 and higher.
• Each page of a PDF file can have a different scaling factor.
• The value of the user unit is normally an integer. However, decimal places can also be processed.
• A page scaling factor can also be set for files whose page length is less than 200 inches.

A Validation Print is a color-accurate print according to ISO 12647-8. Compared to the Contract Proof according to ISO 12647-7, the Validation Print has higher color tolerances. Unlike the contract proof, the Validation Print is neither color binding nor legally binding. However, the Validation Print has smaller color tolerances than a PSD evaluation, which means that digital printing systems that meet this standard support a very high standard.

An example for checking and issuing a printing system is the Validation Print Creation certificate by Fogra. Companies that are certified by Fogra for Validation Print Creation are likely to carry the FograCert logo. By using the certification number, it is easy to check on the Fogra website whether the certification is correct and valid.

You can open the Variable Data panel by selecting Window > Workflow > Variable Data in Adobe Illustrator. This panel allows you to create variable content such as: Text, Barcodes, Images, and Shapes and add them to print files. The Variable Datapanel is divided into three sections.

• VDP Editor for applying Variable Data elements  images, text, graphics, color areas, barcodes, QR codes, etc.

The tools available in the editor are grouped in the toolbar. Depending on the editor, the toolbar can be equipped with different numbers of tools.

A Form XObject represents the possibility to combine a number of PDF objects in the form of a container.

The main purpose for creating XObjects is to describe a container of objects once in the PDF and then use it multiple times in the PDF file, mainly to save storage space. Typical examples are:

• Column title of a multi-page magazine: the column title does not change over a certain distance in the magazine and can therefore be stored only once and referenced multiple times.
• Impositions: Print Items that are imposed multiple times in an Imposition are often stored as XObjects by Imposition programs and referenced for multiple use, mainly to save storage space.
• OPI Workflows: In OPI Workflows - which are rather outdated - XObjects are used to display low-resolution preview images and then replace them with the high-resolution images in the output.

ZIP was developed based on the LZ77 compression method (LZW). In addition to the LZ77 method, the "Shannon Fano Coding" - which, like the Huffman coding, is an entropy coding - was also used, which essentially improved three things:

• Data in which no pattern is repeated is no longer compressed. In the case of LZW, this state has meant that LZW-compressed data can also be larger than the original data. This is not the case with ZIP.
• Each character has a unique pattern in the library, which means that smaller units than one byte are used for encoding frequently occurring characters such as "e".
• The pattern length depends on the character frequency. This results in fewer entries in the library, which in turn reduces memory requirements.