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Scribus PDF/X-3 Info - Q and A
Adding experimental support for PDF/X-3 is a major milestone in the development of Scribus. Scribus is probably the first GPL or Linux/Unix based publishing application to have professional pre-press printing capabilities which meet a demanding, but open ISO standard: ISO 15930-3:2002. This type of support for high quality PDF creation has been, until now, available only in expensive proprietary applications. Moreover, creating "press ready" PDF's has historically been fraught with errors, especially for users unfamiliar with the nuances of postscript, PDF distilling and varying capabilties of imagesetters. The saying "It is hard to create a good PDF, but really easy to mess up", has a great deal of truth. The more common usage of the Adobe Acrobat Distiller family of applications has typically needed knowledge of at least some of the close to 100 Distiller parameters.
In European countries the concept of PDF/X has been more widely accepted than in North America. Much of the push for these standards has come primarily from Germany and German pre-press companies, a worldwide leader in press and high end digital imaging technology.
The creation of PDF/X, with 3 defined ISO standards, is in part, an attempt to provide end users and creators with a measuring stick to vet files as suitable for professional printing or exchange with service bureaus. Scribus now has easy to understand and use options which enable end users to create 100% PDF/X-3 compliant files. By judicious use of PDF options, end users can be assured their files, if they require, too be 100% standards compliant. As always, be certain any PDF's you create can be used in the workflow of your printer or pre-press service bureau. Not all are equiped to handle the latest in PDF technology.
Quick Start to Creating a PDF/X-3 Compatible PDF
- Make sure color managment is installed and working properly. You need at least one CMYK ICC printer profile installed.
- Then in Edit > Preferences >Color Managment make sure color managment is enabled and your preferred defaults for color profiles are chosen.
- Clear the Use PDF 1.4 Transparency Features in Edit > Preferences >Display tab. (PDF/X-3 is based on PDF 1.3)
- SelectFile > Export...> Save as PDF..or select the PDF icon from the tool bar.
This panel will open first and select PDF/X-3 in the compatibility drop down as shown below. This will change the default settings, as needed, automatically.
Next, select the Color tab, as shown below:
Here is where you select color profile choices to embed in the PDF. By not selecting or embedding an ICC profile for solid colors, CMYK is automatically assigned as the color space.
Next,select the PDF/X-3 tab, as shown below:
This is where you can adjust the trim box, as well as embed in the PDF the intended press condition, which is defined by the ICC printing profile. This is probably the most important choice in terms of color profiles, as it affects color throughout the whole document. You can also put in a short note about the document, which is useful later on. Note: Because of the exacting standards of PDF/X-3, some PDF features are disabled including encryption, presentation effects and all fonts are automatically embedded. Likewise, annotations and transparency is disabled. You should carefully follow the advice given in PDF Export for file preparation and choice of image formats.
How has Scribus been able to do this?
- The PDF Exporter within Scribus is now in its fifth generation. By carefully refining the code both PDF output and color management for maximum quality output, Scribus created PDF's can be used with confidence for output to service bureaus that can use a PDF workflow. Many magazines,newspapers and other publications now prefer PDF/X for advertiser created files for example.
- Credit must be given to Marti Maria for creating and actively maintaing littlecms which is the color management system which Scribus uses. littlecms is not a end user application per se, but gives Scribus the color management tools, which were previously only available in proprietary systems.
- Credit also has to be given to the creators and the maintainers of Ghostscript, which since 6.53 has greatly improved in many areas which benefit Scribus. This is why, both Franz Schmid, the developer and I highly recommend using the latest stable version of Ghostscript available for your system. The newest AFPL version 8.0 has added support for overprint mode, Your faithful documenter and tester has broken the printing on his own machine more than once testing Ghostscript betas and upgrades:)
Do I really need color management?
Strticly speaking to meet the spec - no, but from a practical standpoint yes. PDF/X-3 is designed to enhance a color managed PDF workflow, which is point of the latest spec. With images like photos and logo's, it is highly recommended.
What are the differences between PDF-X versions?
In brief, PDF/X-1a requires the following: The color space to be CMYK/greyscale, all the fonts are embedded and the PDF indicates whether it is either pre-trapped = true or not-trapped = false. Think of this as a blind handoff, as there is no certainty of how it will output.
PDF/X-2 is a looser standard - but with the requirement for more knowledge between the supplier and receiver of the file. Fonts are not required to embedded and it is possible to use OPI (Open Press Initiative). PDF/X-2 also allows device dependent color spaces, like CieLab, to be used.
PDF/X-3 allows for ICC color profiles to be resident in the PDF, as well as different output intents and 'DeviceN' (spot color) color space - now supported in the APFL version of Ghostscript 8.0. This also allows overprinting colors.
PDF/X Links:
http://www.ddap.org/resources/index.html
http://www.ipa.org/PDFS/pdfxguide.zip
http://www.ddap.org/resources/PDF-X_AppNotes_V3.pdf
http://www.globalgraphics.com/features/pdfxwfv.htmlMore to follow with this exciting new capability with Scribus...
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