PDF Output Styles for QuarkXPress – Part 1
[June 4, 2019] Quark has redefined PDF output for XPress 2018: The Callas pdfToolbox now works in the background, similar to the print programs from Adobe. A special feature is that XPress PDF files can output not only PDF/X or PDF/A files, but also files that are PDF/X and PDF/A compliant at the same time. As a result, the number of output variations rises sharply.
Definitions – X and A
- PDF/X – the X stands for Blind Exchange (the PDF file is suitable for the "blind" exchange between creators such as layouters or graphic designers and pre-press or printing companies). A validated PDF/X file is stamped with an internal stamp that specifies the printing conditions for which the PDFD file was created.
- PDF/A - the A stands for Archive. A validated PDF/A file is provided with an internal stamp, and the file is protected against modification.
- PDF/X and PDF/A files created directly from layout programs should be subsequently checked to see whether they have received the stamp correctly and whether they actually meet the requirements of the printing process.
The verification can be performed within Acrobat, callas toolboxes and similar PDF workflow tools with special verification profiles.
Terminology – X-1a and X-4
PDF/X and PDF/A are divided into subgroups in which certain settings are required and others are prohibited. Briefly summarized:
- PDF/X-1a files do not contain RGB and LAB images, only CMYK, gray and black-and-white data.
No transparent elements are allowed. However, PDF/X-1a does not specify sufficient image resolution.
A stamp with the selected output condition (e.g. coated or newspaper) is placed in the file.
However, PDF/X-1 does not specify sufficient image resolution.
(RGB may also be used in PDF/X-3 files – PDF/X-3 files where RGB is prohibited are technically PDFX/1a files).
- PDF/X-4 files can contain RGB, LAB, CMYK, grey and black-and-white data - transparent elements are also allowed.
The individual elements in an X-4 file can still retain different (usually RGB) color profiles.
However, PDF/X-4 does not specify sufficient image resolution.
Definitions - X-1a and X-4 in "Plus" version
As the general PDF/X specifications do not contain the individual printing conditions such as digital printing, offset, newspaper or web, but only the framework, various associations and federations ensure that the same output bindings can be used throughout the country or Europe as far as possible. This happens for example with the GWG or with PDFX-ready.
There, recommendations and instructions are created on how to generate PDF/X files from a layout program for the various printing processes. But that's not all: They also provide finished test settings for Acrobat or similar tools, which additionally check the print process-specific specifications and image resolution.
- The layout is produced and attention is paid to the subsequent printing process: If it is to be PDF/X-1a – the Clasic workflow from the last millennium – very comprehensive. Significantly less with PDF/X-4.
- A PDF file is generated from the layout with settings that are optimal for the desired printing process.
- The generated PDF is then checked against the desired printing process in Acrobat or a similar tool.
Time of color conversion of images
Throughout the process of printing images, these images are or have been converted from RGB (from camera or scanner) to CMYK (for the press) at some point. Each RGB to CMYK conversion is immediately an optimal adjustment for only one printing process. Images that are not used in the actually planned printing process lose a lot of the quality that is actually possible and are color falsified. A further falsification then occurs with the PDF/X-1a output: All elements in the PDF are now only marked for a single printing process – so you "lie" to the print shop as a layout designer because other images for other printing processes can also be included.
The conversion of the images from RGB to CMYK can be done:
- before placement in the layout program (early binding) – the layouter must keep an eye on the entire production process over the desired printing process and always apply it immediately to the files,
- output from the layout program (intermediate binding) – the layouter does not have to worry immediately about the printing process in the production process for RGB images, he can even have several different printing processes and paper types operated from his data,
late binding - the layouter only has to deal with a sufficient resolution of the layout
in the print output in the print shop (late binding) – the layouter only has to take care of possible printing processes with sufficient resolution of the images. The printer, on the other hand, can optimize the PDF up to the last minute for the press and type of paper he is currently using.
Definitions – Device and DeviceN
In the printing industry, a "device" is not just a tablet and a smartphone, but a printing press or even just a standardized printing process. "ISO coated v2" is a standardized output process for sheetfed offset and "ISOnewspaper26v4" for daily newspaper printing.
PDF data in which output methods are assigned to individual elements of a layout are device-dependent data.
There are special color profiles to convert device-dependent color data directly between printing processes – this process is called DeviceLink.
Spot colors such as Pantone or HKS are per se device colors -– manifested only in the inking unit with the non-CMYK color in the press. This makes the handling of spot colors in software difficult. This is why an extension of the CMYK color space was created that allows any number of constructs with any number of (N-numbered) spot colors (device-dependent): called DeviceN.
With this prior knowledge, the PDF output styles presented here can now be viewed: »» Part 2