From Scribus Documentation Project
Scribus and PDF
The power and versatility with the PDF export in Scribus is one of its most notable features. Documenting all of its features requires almost a chapter by itself, since PDF really refers to a family of versions – we'll call them flavors. You are encouraged to read this introductory part thoroughly to become familiar with all the PDF features and options.
The platform neutral nature of PDF enables Scribus users to overcome a number of potential barriers to Linux and DTP. Scribus reliably exports high quality, “press-ready” PDF, including advanced PDF 1.4 features, ISO compliant PDF/X-3 and ICC color managed PDFs, thanks to littlecms.
While PDF in one sense is a proprietary standard, it is also widely available on most every computing platform. It is also extremely well documented. The PDF abilities in Scribus enable for repurposing a document. One document can be produced for printing, web download or for presentations similar to StarOffice/OpenOffice.org Impress or MS PowerPoint. That this is a future trend in publishing is indicated by the same strategy in Adobe's InDesign 2.0+ and the new PDF capabilities in Quark Xpress 6 and Adobe Illustrator 10+. In electronic publishing and pre-press production, all of them have seen many enhancements to PDF, which often overcome the limitations of HTML and traditional PostScript, respectively.
Your best viewing/printing results will be with the newest version of Adobe Reader. Please also note, gv and derivatives are not suitable viewers for Scribus EPS or PDFs. Similarly, Adobe Reader on MacOSX is given preference over the built-in Preview app.
If any other PDF or EPS viewer you choose cannot display PDFs from Scribus, but they do view properly in Acrobat Reader, file a bug with the upstream author. In almost all cases it is a limitation of the viewing application. Scribus PDFs are tested regularly with specialist pre-press software to validate their adherence to the published PDF specifications.
PDF Flavors – Which one is best for you?
Like many questions in DTP, this is an important yet not so simple one. Answering it brings up many additional questions and therefore is worthy of some discussion here of what the differences are in these different PDF versions. A higher version does not necessarily produce a “better” PDF and in some cases works against you.
What is the difference between versions PDF 1.2 to PDF 1.5?
Each version roughly parallels the release of a major version of Adobe Acrobat. The short and overly simple answers are:
- PDF 1.2 = Acrobat 3.0 – relatively obsolete now
- PDF 1.4 = Acrobat 5.0, but actually introduced with Illustrator 9. The main difference to concern Scribus users is both transparency and alpha transparency capabilities. This makes a major difference in where a PDF with these features can be printed. It takes either the latest commercial RIPs or certain Level 3 PostScript printers to use these features properly. Even so, not all Level 3 PostScript printers will handle transparency. The latest versions of Ghostscript support the advanced PDF 1.4 features Scribus can create when exporting PDF. The most distinguishing feature of PDF 1.4 for Scribus is the ability to export true transparency. Note: Often, the only way you will be able to print exactly the transparency features viewed on-screen is to export PDF 1.4 and print from Acrobat Reader 5.x or newer.
- PDF 1.5 = Acrobat 6.0 – Among the most interesting for Scribus users: many improvements for “press-ready” PDF, the capability to have true layering within the PDF, PDF-X “pre-flight” capability, more security and interactive features, like the ability to add comments which are separate from the original doc. PDF 1.5 can also support more sophisticated compression options for images using JPEG 2000.
In deciding which version you choose for export, you need to consider the following:
- Where am I ultimately printing? If you are planning to have your files printed commercially, always try to ask the printer first.
- Does my document have transparency features? See above and ensure the rest of your equipment or workflow can support PDF 1.4.
- Am I exporting PDF forms? How do I know end receivers of my file can use it? Do you know the version of Adobe Reader your users will have? The safest is to use PDF 1.3 or 1.4.
- Do I need PDF layers? Only PDF 1.5 supports this and only in the 1.3.x version of Scribus. Be aware support for PDF 1.5 is not complete in most open source viewers. Ghostscript 8.5x does support some, but not all PDF 1.5 features.
What about other kinds of PDF I have read about, like PDF-X and PDF-A?
- In brief, PDF/X-1a requires the following: The color space to be CMYK/greyscale, all the fonts are embedded and the settings within PDF indicate whether it is either pre-trapped = true or not-trapped = false. Think of this as a blind hand-off, 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 be embedded and it is possible to use OPI (Open Press Initiative). PDF/X-2 also allows device independent color spaces, like CieL*a*b*, to be used.
- PDF/X-3 allows for color profiles to be resident in the PDF, as well as different output intents and “DeviceN” (spot color) color space – now supported in the any version of Ghostscript 8.0+. This also allows overprinting colors. You will find more about PDF/X-3 below.
- PDF-A is an ISO standard based on PDF 1.4 for long term storage of public documents in an open format.
A Scribus document can be exported to a PDF file via File > Export > Save as PDF or by a click on the button “Save as PDF” in the Toolbar:
The Preflight VerifierENDNOTE will check your document for errors like overflowing text or missing images. If everything is OK or if you choose to ignore the error messages, the dialog for PDF export will appear.
As you will see, PDF export in Scribus has a great number of options, which will be described in detail below.
Scribus will automatically assign a name, appended with .pdf, and if you haven't named your Scribus document it will be something like Document-1.pdf. In “Output to File”, at the top of the following dialog, you can enter a filename of your choosing. By default, a single PDF file is created containing all the pages of your document, but by checking Output one file for each page, an individual PDF is created for each page of your Scribus document, each with a unique name. For example, if you enter example.pdf as the name of the file and check for single page PDFs, Scribus will create files named example-Page1.pdf, example-Page2.pdf, and so on. Be aware that this does add to the overhead – a 7-page all text document used as a test took up about 4 times the space exported as single pages compared with a single PDF of 7 pages.
- “Export Range”: Select all pages of the document or by page. Individual pages are separated by commas (1,2,4), a range with a hyphen (1–3), or you can use a combination (1,3–7). You can even use this in simple situations for booklet printing.ENDNOTE
- “Rotation and Flipping”: The output can be rotated 90, 180 or 270 degrees and flipped horizontally (left button under rotation) or vertically (right button).
- “Clip to Page Margins”: Content outside the page margins won't appear in the PDF file.
“Compatibility”: There are several version of the PDF specification. Scribus supports 1.3, 1.4, 1.5 and X-3. PDF/X-3 is only available if color management is activated. When PDF/X-3 is selected, the tab “Security” is not active. If your file contains transparencies, choose 1.4 or 1.5.
- “Binding”: Determines the binding (left or right) in the PDF file.
- “Generate Thumbnails”: Creates small preview images of the pages, which can be displayed in Adobe Reader in the “Pages” tab:
- “Save Linked Text Frames as PDF Articles”: Selecting this option will create so-called article threads. You can use them to read an article that is spread over two or more pages by clicking View > Navigation Tabs > Articles in Adobe Reader.
- “Include Bookmarks”: Bookmarks in Scribus can be exported to a PDF file and be used for navigation in a PDF viewer.
- “Include Layers”: If layers are used in Scribus, they can be exported to a PDF file. This feature in only available for PDF version 1.5. You can use this feature in connection with Scribus layers. For instance, it's possible to create a layer that's invisible in a PDF viewer, but will print, like watermarks. Or you can set a layer to visible, but not printable, if you want to prevent parts of the content from being printed.
- “Resolution for EPS Graphics”: The resolution which is used to render text and vector graphics in EPS files in Image Frames. It won't affect bitmap images.
“Compress Text and Vector Graphics”: To achieve smaller file sizes, text and vector graphics can be compressed.
- “Compression Method”: The ZIP algorithm compresses the images without a loss of quality; the JPEG methods results in smaller files, but also means a loss of quality. You shouldn't change the default setting "Automatic", unless someone else requires a specific compression.
- “Compression Quality”: Here you can select the level of the compression that will be applied to the images in the file.
- “Resample Images to”: If this option is checked, the bitmap images in the file will be re-sampled to the resolution set in the spinbox. Note that Scribus will only downscale images, not upscale.
- “Available Fonts”: All fonts used in the document are listed here.
- “Fonts to Embed”: Here are listed the fonts which will be embedded into the PDF.
With the arrow buttons between “Available Fonts” and “Fonts to Embed”, you can choose which font will be embedded in the PDF file. The button “Embed All” selects all fonts for embedding. Embedding means that a copy of the font file(s) will be stored in the PDF file. This is important if you think it might be possible that the printer will have to do some minor corrections in the texts stored in the the PDF file, since the text characters will be contained in the PDF, along with the instructions on how to make the font.
Legal Notice: If you want to distribute the PDF file, read the font license to make sure you have the right to embed the font!
- “Fonts to Outline”: An alternative to embedding a font is to convert all glyphs to PostScript outlines. By using “Fonts to Outline”, any glyph of a selected font will be converted to vector data, and the text as characters will be completely lost. With the arrow buttons beside the “Embed All” button, you can choose which fonts will be converted to outlines. By clicking "Outline All", all fonts in the document will be converted. Converting to outlines is an option if you have no license to embed a font (since embedding would mean distribution). It's also a viable option if you're unsure whether the quality of a font is sufficient for professional printing or when your printer might not have a new enough RIP or imagesetter to accept PDF 1.4. Beware, though, that text which has been converted to outlines can't be edited in a PDF editor anymore.
OpenType Fonts and Unicode TrueType Fonts cannot be fully embedded by default, unless they are simple TrueType fonts that happen to have an *.otf extension. This greatly simplifies handling them in other applications. OpenType Fonts and Unicode TrueType Fonts can be quite large, some larger than 10 MB. OpenType Fonts/Unicode True Type Fonts are automatically converted to outlines in PDF. This allows them to be used in PDF, where often other applications cannot use them. Moreover, embedding Open Type fonts is only supported in PDF 1.6+ (Acrobat 7.0.x) and this technology is quite new.
Like the established presentation programs StarOffice/OpenOffice.org Impress or PowerPoint, PDF files can be used for presentations. Graphical effects for transitions from page to page can be applied to every page. See PDF PresentationsENDNOTE for more information.
In this tab, you'll find some options that will affect the behavior of PDF viewer when it opens the PDF file.
“Document Layout”: These options are controlling the page navigation in the PDF viewer:
- “Single Page”: The document is scrolled page by page.
- “Continuous”: The document is scrolled without considering page breaks.
- “Double Page Left” and “Double Page Right”: Two pages are displayed simultaneously .
“Visual Appearance”: This controls how elements will be displayed in a PDF viewer:
- “Use Viewers Defaults”: The default settings of the viewer will be used
- “Use Fullscreen Mode”: The PDF viewer displays the file in full-screen mode, all menus of the PDF viewer will be hidden. This is particularly useful with presentations.
- “Display Bookmarks Tab”: The bookmarks are shown as a tree.
- “Display Thumbnails”: Previews of the pages will be shown in the PDF viewer.
- “Hide Viewers Toolbar”, “Hide Viewers Menubar”: These settings will hide the respective bars in a PDF viewer.
- “Zoom Pages to fit Viewer Window”: The PDF file is zoomed to the full size of the viewer's display window.
PDF files can be protected by passwords. This is no strong protection for documents. It can be bypassed easily, but might be effective for the general office user, who can disable the printing of a presentation. If you enable Security in the PDF export dialog, when you export PDF 1.3, encryption is 40 bit strength, with PDF 1.4 or later, encryption is 128 bit strength.
The PDF viewer will distinguish between an owner and an user. For both levels, passwords can be set in Scribus.
“Settings”: These settings are controlling the user permissions in a fine-grained way:
- Allow Printing the Document
- Allow Changing the Document
- Allow Copying Text and Graphics
- Allow Adding Annotations and Fields
Note: Do not use password protection in files you send to a printer or service bureau!
These options are very important: here you can control which color space will be used in the exported PDF file.
- “Screen/Web”: the PDF file is created in RGB mode. Use this option, if the PDF should be displayed on screens or will be printed to desktop printers.
- “Grayscale”: all colors are converted to grayscale Note that for precise control of image conversions, you should use an image editor, especially when images come from different sources.
- “Printer”: the document will be color separated and the resulting PDF file uses the CMYK mode. This output intent offers some additional options:
- “Convert Spot Colors to Process Colors”: If enabled, spot colors in your document will be converted to process (CMYK) colors. This will save you additional plates in the printing process. You should, however, use a color swatch from a color vendor to find the correct CMYK equivalents. Moreover, you better talk to your printer before inserting CMYK values in Edit > Colors, since the printing company may have its own conversion tables.
- “Use Custom Rendering Settings”: This is really an advanced set of options, and you should only change them if your printing company expressly requires any changes. Basically, these are settings for a technology called screening.ENDNOTE In CMYK printing, the illusion of continuous-tone colors is created by overlaying dots of ink in Cyan, Magenta, Yellow and Black. Each set of dots will be printed from a separate plate. To achieve the best results, each grid of dots on a plate uses a different angle. It's also possible to change the frequency of dots on plate, depending on the output media. For instance, a newspaper needs a lower frequency than a high quality offset print. It's also possible to change the shape of the dots. Note that the following values can be changed for each processs color separately.
- “Frequency”: The frequency of dots in lpi (Lines per Inch). For regular offset printing, 150 is a reasonable value.
- “Angle”: The angle of grid on each plate. Do not change unless your printing company requires any changes! Sometimes the angles have to be adjusted to avoid moiré patterns.ENDNOTE
- “Spot Function”: Contains a list of available dot shapes. The printing standard is “Ellipsis”.
Note: If you are not sure which mode you should use, you'll be on the safe side with Screen/Web.
Support for PDF/X-3 was a major milestone in the development of Scribus. Scribus was the first page layout application to support a demanding, but open ISO standard: ISO 15930-3:2002. This type of support for high quality PDF creation had been exclusively the realm of expensive proprietary applications. Creating commercial press ready PDFs has historically been fraught with errors, especially for users unfamiliar with the nuances of PostScript, PDF distilling and varying capabilities of plate-setters or digital presses. 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 for PDF creation 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 and earlier 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, currently with 3 defined ISO standards, is, in part, an attempt to provide end users and creators with a vendor neutral measuring stick to vet files as suitable for professional printing or exchange with service bureaus. Scribus 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 required, to be 100% standards compliant. As always, be certain any PDFs you create can be used in the work-flow of your printer's equipment or pre-press service bureau. Not all are equipped to handle the latest in PDF technology. Always consult with the commercial printer you are working with early into your production work. This is almost always good advice when working with commercial printers. This avoids trouble and makes for a much less stressful situation when deadlines approach.
To export a PDF/X-3 file, you have to activate color management in the Document Setup first and then select “PDF/X-3” in the “Compatibility” list in the “General” tab. You also need a color profile, preferably a profile provided by your printer. If you want to make your file 100% compliant with the PDF/X-3 standard, you also have to add the “Info String” (eg. the file name or a comment).
A Trim Box is a rectangular frame, which indicates the real size of the printed page. If you added a bleed of 3mm you can subtract it from the default value.
One of the outstanding features of PDF/X-3 is that it explicitly allows RGB objects to be tagged with ICC profiles. Scribus will use this feature when it's processing RGB layout elements, as this allows for better color-management when separations are created.
Note: Only export to PDF/X-3 if your printer explicitly asks for it.